216 Lab Manual 2003-2004

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The University of Western OntarioFaculty of Engineering Science

DEPARTMENT OF CHEMICAL AND BIOCHEMICAL

ENGINEERING

INDUSTRIAL ORGANIC CHEMISTRY

C.B.E. 216

LABORATORY MANUAL

Instructor: P.A. Charpentier

2nd Edition

Copyright P. Charpentier 2003

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E.S. 216 Industrial Organic Processes Laboratory ManualProf. P. Charpentier 2003-2004

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TABLE OF CONTENTS

1 INTRODUCTION............................................................................................... 31.1 CONVERSION FACTORS ............................................................................... 4

1.2 COMMON ITEMS OF GLASSWARE AND APPARATUS ........................... 51.3 A NOTE TO THE STUDENT ............................................................................ 91.4 PERSONAL CONDUCT .................................................................................. 111.5 HANDLING CHEMICALS AND EQUIPMENT ............................................ 121.6 GENERAL HOUSEKEEPING ......................................................................... 141.7 GUIDELINES FOR PREPARATION OF LABORATORY REPORTS ......... 14

LABORATORY 1 - THE FRACTIONATION OF HYDROCARBONSAND GAS CHROMATOGRAPHY (GC)......................................................... 20

LABORATORY 2 - ANALYSIS OF PETROLEUM FRACTIONS .............. 29

LABORATORY 3 - REDUCTION OF A KETONE TO A SECONDARYALCOHOL ..48

LABORATORY 4 - CATALYTIC HYDROGENATION OF SQUALENE (APOLYUNSATURATED HYDROCARBON).................................................. 51

LABORATORY 5- EPOXIDATION OF 1-TMP AND IODINETITRATION..60

LABORATORY 6 - SYNTHESIS OF AZO-DYES AND UV-VISSPECTROSCOPY............................................................................................. 73

LABORATORY 7 - SYNTHESIS OF DICUMYL ETHER AND NMR SPECTROSCOPY ....80

LABORATORY 8 - SOXHLET EXTRACTION OF CAFFEINE FROMBEVERAGE PLANTS..87

APPENDIX 190

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1 INTRODUCTION

1.1 CONVERSION FACTORS FOR SOMECOMMONLY USED UNITS OF MEASUREMENT

Acceleration m/s 2 ft/s 2 3.281X10 0 3.048X10 -1

g (accel. of gravity) 1.020X10 -1 9.807X10 0 Area m 2 ft2 1.076X10 1 9.290X10 -2

inch 2 1.550X10 3 6.452X10 -4 yard 2 1.197X10 0 8.361X10 -1

Density kg/m 2 g/cm 1.000X10 -3 1.000X10 3 lb/gallon 8.345X10 -3 1.198X10 2

lb/ft3

6.242X10-2

1.602X101

Energy J btu 9.484X10 -1 1.054X10 3 (includes work) calorie 2.387X10 -1 4.184X10 0

(thermochemical)erg 1.000X10 7 1.000X10 -7 ft-lb 7.375X10 -1 1.356X10 0 kW-hr 2.778X10 7 3.600X10 -6

Force N dyne 1.000X10 5 1.000X10 -5 pound force 2.248X10 -1 4.448X10 0

Heat capacity J/kg*K btu/lb* oF 2.390X10 -4 4.184X10 3 (includes entropy) cal/g* oC 2.390X10 -4 4.184X10 3 Length m 1.000X10 10 1.000X10 -10

in 3.937X10 1 2.540X10 -2

ft 3.281X10 0 3.048X10 -1 micron 1.000X10 6 1.000X10 -6 mile 6.213X10 -4 1.609X10 3 yard 1.094X10 0 9.144X10 -1

Mass kg ounce 3.527X10 2 2.835X10 -1 lb 2.205X10 0 4.536X10 -1

Power W btu/hr 3.414X10 0 2.929X10 -1 btu/sec 9.484X10-4 1.054X10 1 cal/sec 2.390X10 -1 4.184X10 0 ft-lb/sec 7.376X10 -1 1.356X10 0 horsepower 1.341X10 -1 7.457X10 2 (550 ft*lb/sec)

Pressure Pa atm 9.869X10 -6 1.013X10 5 (76cm Hg)

bar 1.000X10-5 1.000X10 5 cm of Hg 7.506X10 -3 1.333X10 3

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dyne/cm 2 1.000X10 1 1.000X10 -1 in of Hg 2.961X10 -4 3.337X10 3 kg force/cm 2 1.020X10 -5 9.807X10 4

CONVERSION FACTORS FOR SOMECOMMONLY USED UNITS OF MEASUREMENT CONTD

lb/in 2 (psi) 1.450X10 -4 6.895X10 3 torr 7.501X10 -3 1.332X10 2 (mm of Hg)

Volume m 3 ft3 3.531X10 1 2.832X10 2 (includes capacity) in 3 6.102X10 -1 1.639X10 -5

gallon (U.S.) 2.642X10 2 3.785X10 -3 L 1.000X10 3 1.000X10 -3 ounce (U.S.) 3.381X10 4 2.957X10 -5

psig pounds per square inch gauge psia ponds per square inch absolute

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1.2 COMMON ITEMS OF GLASSWARE ANDAPPARATUS

Most of the apparatus used will be familiar to you, but the following notes may help youin identifying and using specific pieces.

The ERLENMEYER or CONICAL FLASK is used for handling solutions,

and for titrations. It is designed with a narrow neck to minimize loss of

solution through splashing or evaporation.

The FILTER or BUCHNER FLASK is used in conjunction with the Buchner

funnel for vacuum-assisted filtration. It is heavy-walled to give pressure resistance; for

this reason, a Buchner funnel should never be used to heat a

solution. Attach it to the vacuum line or water aspirator with heavy-

wall rubber tubing. For any operation involving vacuum, always

use heavy walled rubber tubing - never use soft tubes like

Tygon. If a water aspirator is used, an empty flask should come

between the filter and the pump to avoid suck-back if the water

pressure falls. The Buchner assembly is top-heavy and should besupported when in operation.

The BUCHNER FUNNEL is used for filtration. It fits through a rubber bung

or cone into the Buchner flask. To use, assemble the flask and funnel, place

a filter-paper flat across the perforated porcelain plate, and wet the paper

with the solvent being used (usually distilled water). Turn on the vacuum

and make sure the paper is correctly seated in the funnel; the filter paper should be cut

slightly smaller than the funnel, but make sure it covers all the holes. Stir the suspension

to be filtered and quickly pour it onto the center of the paper, using a glass rod to guide it.

Filtration will go more quickly if you keep liquid in the funnel. If all of the liquid is

filtered off, the residual solid will pack down into a solid cake, slowing filtration. To

empty the funnel after the solid cake has been washed and sucked as dry as possible,

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loosen the cake around the edge with a spatula, carefully invert the funnel onto a watch-

glass and tap it gently.

The EVAPORATING DISH is used to provide a large surface area to speed up

evaporation. It can be heated on the steam-bath but should never be heated with a

direct flame.

The BURETTE accurately measures volumes to 0.1ml accuracy. When titrating, always

fill the burette to the zero milliliter marking. Your eye should be level with the bottom of

the meniscus in order to take a proper reading of the liquid level.

The TRANSFER PIPETTE accurately delivers one volume (e.g. 5 or10 or25ml).

The PASTEUR or DROPPING PIPETTE is for transferring a few drops.

The SEPARATORY FUNNEL is used for the separation of

liquids with differing densities and for washing. The funnel

should have a properly working stopcock and a stopper of the

correct size. The solution to be separated is poured into the funnel

with the stopcock closed and the funnel stoppered. It is then

shaken vigorously with two hands; one holding the bottom of the

flask between first and second fingers and the other on the stopper

so it does not fall out. This maneuver is performed with the flask

upside down and the stem directed away from people standing by

in case of any splashing. The pressure which may build up inside

the flask is released by holding the funnel upside down and opening the stopcock. Next,

the funnel is placed in a proper size support ring. Enough time is given for the solutions

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to separate into two distinct layers after which the bottom layer can be removed and the

procedure repeated until necessary. ( It is assumed that one knows which layer is to be

kept !)

GAS CYLINDERS with the safety cap off need to be securely strapped to the wall or a

desk in order to prevent them from falling. There is considerable pressure in these

cylinders and care must be taken to control the flow of gases from them. The main

cylinder or tank valve should be closed when not in operation. This valve measures the

pressure present in the tank (i.e. how much gas is left in the tank). The control valve,

usually the second one, gives the pressure reading present in the line connected to the

tank. This is usually a backwards valve, meaning that to reduce pressure it needs to be

turned in the counterclockwise direction. A BUBBLER is usually inserted in the gas line between the cylinder and the connection to the apparatus to be filled with the gas. This

is advantageous for two reasons: 1) the flow of gas is actually seen as it bubbles through

the oil in the bubbler and 2) this is an outlet for the gas if the pressure becomes too high

so that it exits via the bubbler rather than blowing the glassware or connecting tubes.

When working with gas cylinders it is very important that you know and understand how

everything is connected and what function each piece of equipment has.

There are many different shapes of CONDENSERS available

for use. All of them serve the same purpose in conjunction

with distillation apparatus. Their purpose is to cool the vapors

inside the condenser usually with water as coolant. The

condenser is placed before and is tilted toward the receiving

flasks. The glass is blown so that the cooling liquid is

separated from the vapors which are to be condensed. To have

good cooling cold water should flow through the condenser at

all times. This is achieved by connecting the water inlet to the

bottom end of the condenser and the outlet to the top so the

water flows from the bottom up the condenser and out the top.

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ERROR DATA

Volumetric flasks Volumetric pipettes

Volume (ml) Error Volume (ml) Error

10 0.04 1 0.006

25 0.06 2 0.006

50 0.10 5 0.01

100 0.16 10 0.01

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1.3 A NOTE TO THE STUDENT

The following introductory paragraphs are intended to be for your benefit and safety.

The objective of this laboratory is to introduce the student to basic organic reactions and

analytical instrumentation, as used in industrial operations and processes. By performing

the prescribed experiments the student will become familiar with a typical organic

chemical laboratory and the operation of typical analytical instruments. She/he will also

obtain a feeling and routine for generation of analytical results and the technical

capabilities of various instruments. The generated knowledge will enable the student to

better understand the basic chemical principles and control of industrial processes, which

is essential for proper operation of individual units in the plant and the management of processes for optimum performance and product quality, and environmental effects.

Whether in management, processing, design or laboratory, an engineer should have good

knowledge and understanding of the chemistry, measurements and instrumentation being

used in the plant. The important decisions and modifications that an engineer must make

in industry will be based on the results obtained from the laboratory. A good

understanding of possible errors in procedures and instruments is also required and

particularly a good understanding of variables that could affect a result. A lack of this

understanding very often results in erroneous judgments that can affect considerably both

production and quality of the final product.

Although this laboratory does not involve extensive manipulation of hazardous

chemicals, materials that will be analyzed are often flammable and volatile as well as

toxic. Each student must therefore follow strictly all safety procedures and not perform

any unauthorized manipulations with these chemicals prior to consultation with the

instructor or the demonstrator.

Remember: ACCIDENTS ARE CAUSED AND CAN BE PREVENTED!

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A few rules are listed below. A Handbook of Safety Practices in Engineering is supplied

in the laboratory and each student should be familiar with its contents.

The students will work in groups of two or three and enough time will be provided to

finish all the prescribed experiments. If any piece of equipment fails or does not function

properly, students are required to report the problem immediately to the demonstrator or

the instructor and are not allowed to attempt to fix the instrument on their own.

ALL STUDENTS MUST HAVE A LABORATORY BOOK IN WHICH TO RECORD

ALL LAB DATA DURING THE LABORATORY PERIOD. The lab book used in

industry is a legal document. Loose papers for recording of data or comments are not

allowed and will be removed from the lab.

Each student must read the instructions for the particular experiment PRIOR to coming to

the laboratory. He/she should understand the whole procedure and what must be done in

the experiment. This knowledge will be checked periodically by the instructor or the

demonstrator and it will be evaluated.

Equations for all reactions should be written out in your lab notebook before coming to

the laboratory. Also, any calculations required (e.g. theoretical yield, preparation of

solutions) should be written in full in your laboratory notebook before coming to the

laboratory. Record all observations in the lab book including any color changes,

unexpected events, smells, etc. The notebook will be marked from time to time during the

term. Plan your working time in the laboratory! By doing this your laboratory will be a

useful and pleasant experience rather than a frustrating one.

Develop good working habits. Keep your area clean and tidy. Your working area reflects

your working habits and also the quality of your work and results. You are working with

precise instruments and generating accurate data --keep this in mind!

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ALL FLASKS, BEAKERS, CONTAINERS WITH ANY CHEMICALS IN THEM

MUST BE CLEARLY LABELED WITH THE NAME OF THE CHEMICAL AND

DATE!

NO SMOKING, EATING OR DRINKING IS ALLOWED IN THE LABORATORY!

LEAVE YOUR WORKING SPACE, APPARATUS AND GLASSWARE CLEAN AND

IN ORDER BEFORE LEAVING THE LAB!

The demonstrator will sign your lab book ONLY after you have fulfilled this

requirement.

ALL LABORATORY EXPERIMENTS MUST BE DONE DURING THE

ALLOCATED TIME PERIOD. THERE WILL BE NO EXTENSION OF THE LAB

AND NO ADDITIONAL TIME PERIOD AVAILABLE FOR THE EXPERIMENTS,

except under special circumstances such as illness verified by a doctors note.

1.4 PERSONAL CONDUCT

(1) Eye protection (safety glasses with side shields) is mandatory.

(2) Eating and drinking in the lab are strictly forbidden.

(3) Long hair should be tied back.

(4) Laboratory coats are required for cloth and body

protection.

(5) No laboratory work may be performed without the prior permission of Mr.

Milton.

(6) No open toed shoes allowed.

(7) No shorts allowed.

VIOLATION OF ANY OF THESE REGULATIONS WILL MEAN THAT YOU WILL

NOT BE PERMITTED TO WORK IN THE LABORATORY.

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1.5 HANDLING CHEMICALS AND EQUIPMENT

1. Do not taste chemicals.

2. Do not pipet any chemicals by mouth. Use rubber bulb (propipette).

3. Do not pour liquids that are flammable or that do not mix with water into sinks. Pour

them into the provided and labeled containers.

4. Do not mix incompatible chemicals.

5. Do not heat flammable liquids with an open flame.

6. Operations involving volatile or toxic materials are to be conducted in the fume hood.

7. Dispose of solid wastes in garbage pails. Do not use the sinks.

8. Clean up spills (solid or liquid) at once.

9. Return chipped or broken glassware to the demonstrator.

10. Be sure the apparatus is placed properly. Do not move instruments without proper

consultation with the demonstrator.

11. When heating a test tube make sure that it is not pointing towards yourself or other

people in the vicinity, so no damage will result if the contents suddenly dump out.

12. Never apply force to any glass apparatus. Many serious cuts are caused by the sudden

fracture of glass under strain from misuse. In particular, never use force in an

attempt to push a thermometer or glass tube through a hole in a cork or rubber.

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13. Never heat a tightly stoppered flask even if it is empty-----it will explode.

14. Do not attempt to buttress a laboratory assembly with makeshift supports such as

books, pencils and the like. Use several ring stands if necessary. Round bottom flasks

cannot stand freely on the bench----use a special cork support or place the flask into a

beaker.

15. Do not attempt to break up a solid in the bottom of a flask by punching the solid with

a glass stirring rod. The rod may either fracture in your hand or puncture the bottom

of the flask.

16. Avoid shortcuts! If you have an idea for an improvement talk it over with your

demonstrator; if no objections, try it; if it is successful, tell us about it!

17. There are certain necessary precautions associated with particular chemicals or

experiments. Your demonstrator will point these out when required.

18. If you are not familiar with a piece of apparatus or an experimental procedure ask

for help. Dont just try to muddle through without knowing what you are doing.

19. Chemical waste should be disposed of in the labeled waste containers

provided. Halogenated chemicals must be disposed of separately from non-

halogenated chemicals. Nothing should go down the drain! Dispose of all chemicals

in the bottles marked for the specific lab.

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1.6 GENERAL HOUSEKEEPING

1. Keep benches clean and orderly and sinks clean. You must leave your portion of the

bench clean at the end of the lab period.

2. Aisles and floors are to be kept free of obstructions. Keep cupboard doors and

drawers closed when not in use.

3. Hang coats on the rack. No coats are permitted on tables or benches.

4. Laboratory doors MUST be unlocked during lab period.

1.7 GUIDELINES FOR PREPARATION OF LABORATORY REPORTS

Laboratory reports should be written as though they were short technical reports. Thus

Tables and Figures should always be referred to in the prose text of the report, i.e. they

should not appear on their own.

The report should be written in the past tense, since it is a description and a correlation of

past observations. The present tense may be used in referring to laws of nature, properties

of materials etc. which are independent of time. Thus, for instance, in a particular

experiment The ambient temperature equaled 22 C; on the other hand, The ambient

temperature equals about 20 C .

TITLE PAGE

Title of experiment

Name of person writing the report

Name of experimenters

Date when the experiment was performed

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All Formal reports must be TYPED

ABSTRACT

The Abstract should summarize the entire report. It should state clearly and briefly the

objectives, methods, results and conclusions of the lab.

Objective: State the objective or purpose of the lab

Method: In one or two sentences, summarize the methods, including scientific and

common names of organisms and techniques used.

Results: Summarize what was found in the study

Conclusions: State the significance of the results in relation to the objective.

INTRODUCTION

The Introduction should describe the scope and the purpose of the lab and include any

background information necessary to understand the experiment.

State the general problem. Give a brief statement of why the general topic is relevant and

important. Define any specialized terms or concepts (e.g. the concept of distillation)

likely to be encountered later in the lab report. Supply sufficient background (historical

and theoretical) information to allow the reader to evaluate and understand the results of

the study without needing to refer to other publications.

State the specific objective or purpose of the lab and the approach to be used. The

purpose states what you are investigating and why; how you perform the investigation

should be described later in the Methods and Materials.

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MATERIALS AND METHODS

The Methods section should describe what was done and how it was done. It should be

written in the past tense with active voice, and in paragraph form.

The Materials and Methods section should provide only enough detail to permit a

competent worker to evaluate the validity of the experiment and to repeat it, if necessary.

It should not be simply a recipe of all the steps involved. State the names (IUPAC if

possible) of the chemicals used, the instruments, equipment and pattern of replication.

Describe any unusual numerical calculations and state the statistical technique used toanalyze the data.

RESULTS

The Results section should present the data collected in a summarized form and describe

only the key features of these data, emphasizing trends or patterns that are relevant to the

hypotheses being tested. Interpretation of the data is reserved for the discussion section.

Do not present the same data in both a table and figure i.e. place table of raw data in an

appendix and place figure in the results section. Titles of tables and figures should

contain enough information to understand the contents without reference to the text. The

number and title are placed at the top of a table, and at the bottom of figure.

Guide the reader through your figure (s) and table (s) in a logical and systematic manner,

pointing out trends and differences that pertain to the objective (s) of the report. Simply

state what you found in your study, without inference or reference to "expected" results.

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DISCUSSION

The Discussion section should provide an explanation and interpretation of your results

and indicate the significance of the results to the hypothesis being tested. Results of

previous studies on the same topic should be compared with yours, with an explanation of

why your results are different from previous studies, if necessary.

State how and why your results either support or do not support the objectives and

hypotheses. REMEMBER: results are results, they are never wrong simply by being

different from either your expectations or from other investigations. Draw conclusionsabout the hypotheses (objectives) of your study, based on all data available in the current

studies.

APPENDIX

Includes all raw experimental data, e.g. time vs. temperature data points, sample

calculations, and any other information or data used for the experiment and calculations.

REFERENCES

The Reference section should be a list of all books, journals, and other materials cited in

the body of the paper.

The surname of the author(s) and the year of publication should be inserted in the text at

an appropriate place:

"Smith (1991) compared..." or "... have been recently compared (Smith, 1991)."

If the reference has more than 2 authors, include only the surname of the first author,

followed by "et al."

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"Smith et al. (1991) compared..." or "... have been recently compared (Smith et al.,

1991)."

When listing more than one citation at a given point in the text, list them in

chronologically by first author, but for 2 (or more) papers, published in the same year, list

these alphabetically:

"(Jones, 1978; Black et al., 1989; Smith, 1989; Jones and Smith, 1991)"

If an author or group of authors has published more than one article in a given year, you

can distinguish between these articles by placing a letter postscript after the publicationyear:

"(Black and Smith, 1990a; Black and Smith, 1990b)"

List all references in alphabetical order, sorted by the author(s)' last name(s). In cases

where the same author or group of authors has/have published multiple papers that you

have cited, then arrange these references in chronological order.. All authors must be

given in the reference list - the abbreviation "et al." Is used only in the text. The following

are examples of the punctuation, style and abbreviations that may be used for references

(note: the headings given here are not to be included in your reference list).

Journal article:

Jones, R.S., E.J. Gutherz, W.R. Nelson and G.C. Matlock. 1989. Burrow utilization by

yellowedge grouper, Epinephelusflavolimbatus, in the northwestern Gulf of Mexico. Env.

Biol. Fish. 26: 277-284.

Chapter in a Book:

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Gross, M.T. 1984. Sunfish, Salmon and evolution of alternative reproductive strategies

and tactics in fishes. Pp. 55-57. In: G.W. Potts and R.J. Wooten (eds.) Fish reproduction:

strategies and tactics. Academic Press, London.

Book:

Siegel, S. 1956. Nonparametric statistics for the behavioral sciences. McGraw-Hill, New

York. pp. 312.

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ORGANIC CHEMISTRY LABORATORIES

LABORATORY 1 - THE FRACTIONATION OF HYDROCARBONS AND GAS

CHROMATOGRAPHY (GC)

(2 LAB PERIODS)

I. INTRODUCTION

Mixtures of organic compounds can be separated by distillation. One such mixture is

crude oil. Oil refineries fractionate crude oil by distillation into products such as gasoline.Separation by distillation is based on the difference in boiling points. The composition

and uses of crude oil fractions is summarized in Table 1.1

Table 1.1 Petroleum constituents

FRACTION DISTILLATION

TEMPERATURE (bp),oC

CARBON NUMBER GENERAL USES

Gas below 20 C 1-C4 uses as for natural gas

Petroleum ether 20-60 C 5-C6 solvent, dry-cleaning

Ligroin (light

naphtha)

60-100 C 6-C7 useful as fuel or

chemicals feedstock

Natural gasoline 40-205 C5-C10, cycloalkanes straight run gasoline

Kerosene 175-325 C 12-C18, aromatics jet, tractor, heating fuel

Gas oil above 275 C 12 and higher diesel and heating fuel

Lubricating oil non-volatile liquids long chains attached

to cyclic structures

lubricants or cracked to

give lighter fractions

Asphalt or

petroleum coke

non-volatile solids polycyclic structures paving, coating and

structure uses

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SEPARATION BY DISTILLATION

Simple Distillation:

In a simple distillation, the mixture of compounds to be separated is boiled, and the

vapors are condensed. The vapor phase is always richer in the more volatile compound

(lower boiling point). For instance, if we boil the liquid with a composition of X o as

shown in Figure 1.1, the vapor will have a composition of Y o, which is richer in the low

boiler. By condensing the vapors we get a head product rich in the low boiler, while the

bottom product will be nearly pure high boiler. This method gives good separation only

if there

is a reasonably big difference between the boiling points of the high and low boilers. The

method can be further refined by redistilling the condensed head fractions.

Reflux Cooling (Deflegmation):

The head product can be enriched to have more low boilers by using a reflux condenser

shown in Figure 1.2. To achieve this a fraction of the vapors is condensed back to the

Figure 1.1 Simple Distillation

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boiler. This can be understood from Figure 1.3. When we boil a liquid with composition

Xo, the vapors would have a composition of Y o. The reflux cooler condenses a fraction of

the vapors, reducing the temperature to P. This point is in the two-phase region, thus the

vapor separates to the refluxing liquid with a composition of X D, going back to the boiler,

and the head product with a composition of Y D. It can be easily seen that the head

product is richer in the low boiler than in a simple distillation (Y o).

Rectification:

To further improve the separation, the refluxing liquid can be contacted with the

evaporating vapor - this is called rectification (Figure 1.4). To understand the principle of

rectification lets assume that the composition of the vapor, A, and the refluxing liquid, B,

Figure 1.3 Reflux coolingFigure 1.2 Reflux cooling setup

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is equal, so we can represent it as P on Figure 1.5. The vertical position of P depends on

the ratio of A to B. P separates into two phases, with compositions X L and Y D. This is the

representation of the equilibrium of one theoretical plate. In the industrial distillation

towers there are a number of plates (with lower efficiency than the theoretical plates). For

the separation of components with similar boiling points, as many as 200 plates are used.

In the present lab, a three component system will be separated by a simplified

rectification. The reflux condenser to be used is called a Vigreux column, and the spikes

serve as plates to force the vapors to bubble through the condensing liquid, thereby

improving the separation. A better lab distillation head shown in Figure 1.6 almost

perfectly simulates the industrial towers (Figure 1.7).

Figure 1.4 Rectification setup Figure 1.5 Rectification

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II. MATERIALS

unknown mixture of hydrocarbons (prepared by the demonstrator) consisting of

toluene, 2-methyl-butene and hexane

III. EQUIPMENT 1000ml round bottom boiling flask

fractionation column (Vigreux)

condenser

distributor (cow)

4, 250ml round bottom receiving flasks

green, plastic glassware clamps

heating mantle with power control unit

thermometer

clamps

Gas Chromatograph

Figure 1.7 Industrial distillationtower

Figure 1.6 Laboratory rectificationhead

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IV. PROCEDURE

Before beginning the distillation, make an injection of the hydrocarbon (HC) mixture you

received from the TA into the gas chromatography (GC) unit. Refer to the GC section

under Instrumentation found in this lab manual for background information. The GC will

produce a strip chart with a number of peaks that relate to the volume percent of each of

the HCs in the mixture, as well as some other peaks. Normalize the peak areas of the

three HCs to equal 100 percent of the total peak area. (i.e.: use only the areas of the

peaks that relate to the HC peaks) Then calculate the percentage of each of the fractions

in the mixture as indicated by the GC analysis. These are the values that will determine

the success of your distillation. You can then proceed with the distillation of the HCmixture.

If you do your distillation correctly, the total volume of the fractions collected plus the

remaining bottom fraction (left in the boiling flask) should equal the volume of the

original mixture. Also, the percentage of each HC in the mixture should correspond to

the original GC analysis. Doing this will require several simple but necessary

calculations. The interesting part of the calculation is that your fractions will probably

be a mixture of several HCs, with one HC dominating. You will have to calculated the

total volume of each HC from the volume of that HC in each of the fractions and the

bottom. (The bottom is what is left over in the boiling flask at the end of the distillation)

Include in your report a table listing the volume of each HC collected in each fraction,

and the sum of each HC in the entire mixture. Convert these volumes to percentages, and

compare this to the original GC analysis of the small sample of the mixture, again in table

format. Remember to title each table and figure appropriately. Proper form and style are

very important, even if you are not satisfied with the results of your experiment.

To perform the distillation, set up the equipment as shown in Figure 1. Pour a measured

volume (300 mL) of a prepared HC mixture into the boiling flask. Prepare a table and

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take time/temperature measurements throughout the distillation every 60 seconds. This

raw data will be plotted and submitted with the report. (do not submit the raw data)

Slowly heat the mixture until you have achieved a gentle boil and a steady reflux in the

Vigreaux column. As soon as you begin to see condensation occurring in the condenser,

the first temperature plateau has been reached. Maintain this temperature and collect the

liquid (first cut) in a collection flask. Usually a waste cut is taken to eliminate impurities,

but in this case we want to recover as much of the HC mixture as possible. Also, past

distillation experiments have shown that the majority of the low boiler is fractionated

very early in the experiment.

When the dripping stops, you have exhausted the first cut. Increase the temperature and

repeat the procedure. Keep up with the time/temperature data. When the second cut is

exhausted, you will be left with the third cut (bottom cut) in the boiling flask. Never letthe boiling flask run dry! At this point you will have completed the distillation. Turn

off the heat. After the equipment has cooled it can be dismantled and returned to the

storage bins underneath the lab benches. In the meantime, measure and record the

volume of each cut, and prepare a sample of each cut for storage in the lab fridge. Make

sure you have identified your samples in such a manner that anybody would be able to

continue with the experiment.

A portion of the samples you have collected will be injected into the GC. This is a pretty

straightforward operation. You will identify the fractions based on the time it takes for

the material to pass through the system. Different substances pass through the system at

different lengths of time, depending on their interaction with the G.C. column packing

material.. This is the basis of GC. Once you have created a GC trace for each cut, you

can then complete the calculations as outlined, and prepare your report in compliance

with the Guidelines for Preparation of Laboratory Reports included in your lab manual.

V. PRELAB QUESTIONS

Submit to the TA prior to beginning the laboratory session.

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1) Draw the structures of toluene, 2-methyl-butene, and hexane. List their physical

properties (molecular weights, density, boiling point, refractive index and melting

point)

VI. SUMMARY OF REQUIREMENTS FOR REPORT

1) In table form show the calculated percentages of each fraction in the mixture prior

to distillation.

2) In table form show the time/temperature measurements recorded throughout the

distillation ( every 60 seconds). Plot the above.

3) Submit the GC trace for each cut and the basis for identification of the fraction

4) Tabulate the volume of each HC cut collected and the volume sum of all the HCfractions in the entire mixture. Convert volumes to percentages, and compare to the

original sample analyzed prior to distillation.

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EXPERIMENT 2 : ANALYSIS OF PETROLEUM FRACTIONS

(2 LABORATORY PERIODS)

Purpose: To familiarize the student with the instruments and analysis used in the

petroleum and petrochemical industries.

PART 1. ASTM DISTILLATION OF PETROLEUM PRODUCTS (ASTM D86-61).

This method of testing is intended for use in the distillation of motor gasolines, aviation

gasolines, aviation turbine fuels, naphthas, kerosenes, oils, distillate fuel oils, and similar

petroleum products.

Definitions:

Initial Boiling Point -The thermometer reading which is observed at the instant that the

first drop of condensate falls from the lower end of the condenser tube.

End Point -The maximum thermometer reading attained during the test, which usually

occurs after the evaporation of all liquid from the bottom of the flask. The term

"maximum temperature" is a frequently used synonym.

Dry Point -The thermometer reading which is observed at the instant the last drop of

liquid evaporates from the lower point in the flask. Any drops or film of liquid on the side

of the flask or on the thermometer are disregarded.

Decomposition Point -The thermometer reading which coincides with the first indications

of thermal decomposition of the liquid in the flask.

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NOTE: Characteristic indications of thermal decomposition are an evolution of fumes

and erratic thermometer readings which usually show a decided decrease after any

attempt is made to adjust the heat.

Percent Recovered -The volume in milliliters of condensate observed in the receiving

graduate, in connection with a simultaneous thermometer reading.

Percent Recovery -The maximum percent recovered, as observed in accordance with

Procedure.

Percent Total Recovery -The combined percent recovery and residue in the flask, as

observed in accordance with Procedure.

Percent Loss -100 minus the percent total recovery.

Percent Residue -The percent total recovery minus the percent recovery, or the volume of

residue in milliliters if measured directly.

Percent Evaporated -The sum of the percent recovered and the percent loss.

Outline of Method

A lOO-ml sample is distilled under the prescribed conditions which are appropriate to its

nature (Table 1). Systematic observations of thermometer reading and volume of

condensate are made, and from these data the results of the test are calculated and

reported.

Apparatus -A typical assembly of the apparatus is shown in Figure 1.

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Preparation of Apparatus

(a) Fill the condenser box to cover the condenser tube with chopped ice. Add sufficient

water to cover the condenser tube. Prepare a similar cold-water bath for the graduate.

(b) Remove any residual liquid in the condenser tube by swabbing with a piece of soft,

lint-free cloth attached to a cord or copper wire.

(c) Measure 100 ml of the sample in the graduated cylinder and transfer it as completely

as practicable to the distillation flask, taking care that none of the liquid flows into the

vapor tube.

(d) Fit the thermometer, provided with a snug-fitting, well-rolled cork, tightly into the

neck of the flask so that the bulk is centered in the neck and the lower end of the capillaryis level with the highest point on the bottom of the inner wall of the vapor tube.

(e) Place the flask containing the 100-ml charge in its support; and by means of a cork

through which the vapor tube has been passed, make a tight connection with the

condenser tube. Adjust the flask so that it is in a vertical position and so that the vapor

tube extends into the condenser tube for a distance of 1 to 2 in.

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(f) Place the graduate that was used to measure and charge, without drying, into its bath

under the lower end of the condenser tube so that the end of the condenser tube is

centered in the graduate and extends therein for a distance of at least 1 in, but not below

the 100-ml mark. Cover the graduate closely with a piece of blotting paper so similar

material, suitably weighted, which has been cut to fit the condenser tube snugly. Maintain

the level of the bath around the graduate so that it is at least as high as the 100-ml mark.

(g) Note and record the prevailing barometric pressure, and proceed at once with the

distillation as directed in the following section.

1.4 Procedure

Apply heat to the distillation flask and contents. Immediately after observing the initial boiling point, move the graduate so that the tip of the condenser touches its inner wall.

Continue to regulate the heating so that the rate of condensation into the graduate is 4-5

ml/min.

In the interval between the initial boiling point and the end of the distillation, observe and

record whatever thermometer readings at prescribed percentages recovered, and/or

percentages recovered at prescribed thermometer readings are necessary for the

calculation and reporting of the results of the test as prescribed in the following section.

Record all volumes in the graduate to the nearest 0.5 ml and all thermometer readings to

the nearest 1.0F (0.5C).

NOTE : In cases in which no specific data requirements have been indicated, record the

initial boiling point, the end point or dry point or both, and thermometer readings at 5%

and 95% recovered and at each multiple of 10% recovered from 10% to 90% inclusive.

If either a thermometer reading of 700F (371C) or a decomposition point is observed,

discontinue the heating and resume the procedure as directed in the second paragraph

following. Otherwise, continue the heating until the end point is reached.

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Observe and record the end point or dry point or both, as required, and discontinue the

heating. At the end point, observe if all the liquid has evaporated from the bottom of the

flask. If not, include a note of this fact in the report as prescribed in the following section.

While the condenser tube continues to drain into the graduate, observe the volume of

condensate at 2-minute intervals until two successive observations agree. Measure this

volume accurately and record it, to the nearest 0.5 ml, as percent recovery. If the

distillation was previously discontinued under the conditions given in the second

paragraph preceding, deduct the percent recovery from 100, report this difference as

"Percent Residue and Loss", and omit the procedure given in the next two paragraphs.

After the flask has cooled, pour its contents into the condensate in the graduate and allow

to drain until no appreciable increase in the volume of liquid in the graduate is observed.Record this volume, to the nearest 0.5 ml, as percent total recovery.

Deduct the percent total recovery from 100 to obtain the percent loss.

1.5 Calculations and Reporting

Report (and plot) the data specified under section 1.1 and the pressure under which the

measurements were made.

1.6 Question

(a) How many components are present in the sample? What are they?

PART 2. API GRAVITY OF PETROLEUM AND ITS PRODUCTS (ASTM D287-

55)

This method describes a procedure for the determination by means of a glass hydrometer

of the API gravity (in vacuum) of crude petroleum and of petroleum products normally

handled as liquids and having a Reid vapor pressure of 26 lbs. or less. Results are

determined at 60F or converted to values at 60F by means of standard tables.

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Definition -API Gravity is defined by the following equation:

API Gravity. deg. = (141.5/ (sp.gr.60/60F )) -131.5

2.1 Apparatus

The following apparatus is required:

Hydrometers , of glass, graduated in degrees API (in vacuum) as listed in Table l and

conforming to the Tentative Specifications for ASTM Hydrometers (ASTM Designation:

EI00). For routine. testing of petroleum products, the long form of hydrometer (IH to

10H) should be used.

Thermometer , having a range of -5F to +215F and conforming to the requirements for

Thermometer 12F as prescribed in ASTM Specifications El.

Hydrometer Cylinders , made of metal, clear glass, or plastic. For convenience in

pouring, the cylinder may have a lip on the rim. The side diameter of the cylinder shall be

at least 25 mm greater than the outside diameter of the hydrometer used in it. The height

of the cylinder shall be such that the length of the column of sample it contains is greater

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by at least 25 mm than the portion of the hydrometer which is immersed beneath the

surface of the sample.

Temperature of Test -The gravity determined by the hydrometer method is most

accurate at or near the standard temperature of 60F; use this or any other temperature

between OF and 195F for the test, so far as it is consistent with the type of sample and

necessary limiting conditions shown In Table 2.

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2.2 Procedure

Pour the sample into the clean hydrometer jar without splashing so as to avoid the

formation of bubbles and to reduce to a minimum the evaporation of the lower-boiling

constituents of the more volatile samples. For the more volatile samples, transfer to the

hydrometer cylinder by siphoning. Remove any air bubbles formed, after they have

collected on the surface of the sample, by touching them with a piece of clean filter paper

before inserting the hydrometer. Place the cylinder containing the sample in a vertical

position in a location free from air currents. Take precautions to prevent the temperature

of the sample from changing appreciably during the time necessary to complete the test.

During this period, the temperature of the surrounding medium should not change any

more than 5F.

Lower the hydrometer gently into the sample, and when it has settled, depress it about

two scale divisions into the liquid and then release; keep the rest of the stem dry as

unnecessary liquid on the stem changes the effective weight of the instrument and so

affects the reading obtained. With samples of low viscosity, a slight spin imparted to the

instrument on releasing assists in bringing it to rest, floating freely away from the walls

of the hydrometer cylinder. Allow sufficient time for the hydrometer to become

completely stationary and for all air bubbles to come to the surface. This is particularly

necessary in the case of the more viscous samples.

When the hydrometer has come to rest, floating freely, and the temperature of the sample

is constant to O.2F, read the hydrometer to the nearest scale at which the surface of the

liquid cuts the scale. Determine this point by placing the eye slightly below the level of

the liquid and slowly raising it until the surface, first seen as a distorted ellipse, appears to

become a straight line cutting the hydrometer scale.

To make a reading with nontransparent oils, observe the point on the hydrometer scale to

which the sample rises above its main surface, placing the eye slightly above the plane

surface of the liquid. This reading requires a correction. Determine this correction for the

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particular hydrometer in use by observing the height above the main surface of the liquid

to which the oil rises on the hydrometer scale when the hydrometer in question is

immersed in a transparent oil having a surface tension similar to that of the sample under

testing.

Observe the temperature of the sample to the nearest O.25F immediately before and

after the observation of the gravity, the liquid in the cylinder being thoroughly but

cautiously stirred with the thermometer, the whole of the mercury thread being immersed.

Should these temperature readings differ by more than 1F, repeat the temperature and

gravity observations when the temperature of the sample has become more stable. Record

the mean of the thermometer reading before and after the final hydrometer reading, to the

nearest degree Fahrenheit, as the temperature of the test.

NOTE: When thermo-hydrometers are used, stir the sample by carefully raising and

lowering the hydrometer. It is satisfactory in this case to read the thermometer scale after

the hydrometer reading has been observed.

2.3 Result

Report the API gravity of the petroleum sample provided.

PART 3. SAYBOLT VISCOSITY (ASTM D88-56)

This method describes procedures for the empirical measurement of Saybolt viscosity of

petroleum products at specified temperatures between 70F and 210F. A special

procedure for waxy and resinous materials is also included.

NOTE: A fundamental and preferred method for measuring viscosity is by the use of

kinematic viscometers as outlined in ASTM Method D445, Test for Kinematic Viscosity.

This method requires smaller samples, less time, and gives greater accuracy.

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Saybolt Universal and Saybolt Furol viscosities may be obtained from kinematic

viscosity values by the use of conversion tables given in ASTM Method D446 -

Conversion of Kinematic Viscosity to Saybolt Universal Viscosity; and ASTM Method

D666 -Conversion of Kinematic Viscosity to Saybolt Furol Viscosity, respectively.

Definition

(a) Saybolt Universal Viscosity -The efflux time in seconds of 60 ml of sample flowing

through a calibrated Universal orifice under specified conditions.

(b) Saybolt Furol Viscosity -The efflux time in seconds of 60 ml of sample flowing

through-a calibrated Furol orifice under specified conditions.

The Furol viscosity is approximately one-tenth the Universal viscosity and isrecommended for those petroleum products having viscosities greater than 1000 seconds

(Saybolt Universal), such as fuel oils and other residual materials.

The word "Furol" is a contraction of fuel and road oils.

3.1 Outline of Method

The efflux time in seconds of 60 ml of sample, flowing through a calibrated orifice, is

measured under carefully controlled conditions. This time is corrected by an orifice factor

and reported as the viscosity of the sample at that temperature.

3.2 Apparatus

Viscometer and Bath -The viscometer shall be constructed entirely of corrosion-

resistant metal. The orifice tip, Universal or Furol, may be constructed as a replaceable

unit in the viscometer. Provide a nut at the lower end of the viscometer for fastening it in

the bath. Mount vertically in the bath and test the alignment with a spirit level on the

plane of the gallery rim. Provide a cork or other suitable means to prevent the flow of

sample until the start of the test; a small chain or cord may be attached to the cork to

facilitate rapid removal. The bath serves both as a support to hold the viscometer in a

vertical position as well as the container for the bath medium. Equip the bath with

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effective insulation, with a coil for heating and cooling, and with thermostatically

controlled heaters capable of maintaining the bath within the functional parameters given

in Table 3. The heaters and coil should be located at least 3 in. from the viscometer.

Provide a means for maintaining the bath medium at least 1/4 in. above the overflow rim.

The bath media are given in Table 3.

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3.3 Preparation of Apparatus

Use a Universal orifice for lubricants and distillate materials with efflux times greater

than 32 seconds to give the desired accuracy. Liquids with efflux times over 1000

seconds are not conveniently tested with this orifice.

Use a Furol orifice for residual materials with efflux times greater than 25 seconds. The

Furol eff1ux is approximately one-tenth the Universal efflux time.

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NOTE : The Universal orifice is used at 70, 100, 130 and 210F. The Furol orifice is

used at 77, 110, 122 and 210F.

Set up the viscometer and bath where they will be free from drafts and rapid changes in

air temperature. Locate them so that the sample will not be contaminated by dust or

vapors during the test.

Viscosity determinations shall not be made at temperatures below the dew point of the

room's atmosphere. Room temperatures up to 100F will not introduce errors in excess of 1.0 percent. For standardization and referee tests, the room temperature shall be kept

between 68 and 86F and the actual temperature recorded.

Fill the bath at least 1/4 in. above the overflow rim of the viscometer. Table 4 lists

recommended bath media for each test temperature.

Provide adequate stirring and thermal control for the bath so that the sample will not

fluctuate more than 0.05F after reaching the test temperature.

Clean the viscometers with an effective nontoxic solvent and remove all solvent from the

gallery and viscometer.

NOTE : The plunger commonly supplied with the viscometer should never be used for

cleaning as the overflow rim and walls of the viscometer may be damaged by its use.

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Calibration of Viscometer

Calibrate the Saybolt Universal viscometer at periodic intervals by measuring the efflux

time at 100F of an appropriate viscosity standard, following the procedure for standards

given below.

Viscosity standards are available from two sources. These standards may be used with

equal confidence provided they are used immediately after opening and not stored for re-

use as permanent viscosity standards.

Standards Conforming to ASTM Saybolt Viscosity Standards

Viscosity Oil Standards conforming to the requirements of ASTM Viscosity Oil

Standards for viscometer calibration having certified Saybolt viscosity values established

by cooperative determinations of kinematic viscosity values. The kinematic values are

converted to Saybolt Universal and Saybolt Furo1 viscosity values by means of

conversion tables given in ASTM Methods 0446 and 0666, respectively. The Viscosity

Oil Standards are oils with approximate Saybolt viscosities as shown in Table 5.

3.4.2 NBS Viscosity Standards

National Bureau of Standards liquid viscosity standards having accurate values supplied

with each sample. Standard SB has a Saybolt Universal viscosity of approximately 300

sec. at 100F. Standard SF has a Saybolt Furol viscosity of approximately 100 seconds at

122F.

3.4.3. Routine Calibrations

The viscosity standards may also be used for routine calibrations at other temperatures as

shown in Table 5.

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3.4.4 Other Viscosity Standards

Other reference liquids, suitable for routine calibrations, may be established by selecting

stable oils covering the desired range and determining their viscosities in a viscometer

calibrated with a standard conforming to ASTM requirements or an NSB standard as

described herein.

The efflux time should equal the certified Saybolt viscosity value. If the efflux timediffers from the certified value by more than 0.2%, calculate a correction factor, F, for the

viscometer as follows:

F = V/T

where F = certified Saybolt viscosity of the standard, and

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t = efflux time in seconds at 100F.

NOTE : The correction factor applies to all viscosity levels and for all temperatures,

provided the calibration is based on viscosity standard having an efflux time between 200

and 600 sec.

Calibrate the Saybolt Furol viscometer at 122F in the same manner as above, using a

viscosity standard having a minimum efflux time of 90 seconds.

Viscometers or orifices which have corrections in excess of 1.0 percent shall not be used

for routine testing.

3.5 Procedure

If the test temperature is above room temperature, the test may be expedited by

preheating the sample to not more than 3F of its flash point (see ASTM Method D93).

Test for Flash Point by Means of the Pensky-Martens Closed Tester), as volatility losses

may alter its composition.

Insert a cork stopper, having a cord attached for its easy removal, into the air chamber at

the bottom of the viscometer. The cork shall fit tightly enough to prevent the escape of

air, as evidenced by the absence of oil on the cork when it is withdrawn.

Filter the prepared sample through a 100-mesh screen directly into the viscometer until

the level is above the overflow rate.

Stir the sample until its temperature remains constant within 0.05F of the test

temperature during 1 minute of continuous stirring. Stir with a viscosity thermometer

equipped with a thermometer support (Figure 3). Use a circular motion at 30 to 50 r.p.m.

in a horizontal plane.

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NOTE : Never adjust the temperature by immersing hot or cold bodies into the sample.

Such thermal treatment may affect the sample and the precision of the test.

Remove the thermometer from the sample. Quickly remove the oil from the gallery until

its level is below the overflow rim. This is done by placing the tip of the withdrawal tube

at one point in the gallery and applying suction. Do not touch the overflow rim with the

withdrawal tube, or the effective head of the sample will be reduced.

Place the receiving flask where the stream of oil from the bottom of the viscometer will

just strike the neck of the flask. The graduation mark on the flask shall be between 10 and

13 cm from the bottom of the viscometer tube.

Snap the cork from the viscometer using the attached cord. At the same instant start the

timer. Stop the timer the instant the bottom of the meniscus reaches the graduation mark.

Record the efflux time in seconds.

Report the corrected time in seconds as the Saybolt Universal viscosity or Saybolt Furol

viscosity of the oil at the temperature at which the test was made.

Report the values below 200 seconds to the nearest 0.1 second. Report all values of 200

seconds or higher to the nearest whole second.

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EXPERIMENT 3 : REDUCTION OF A KETONE TO A SECONDARY ALCOHOL

(1 LABORATORY PERIOD)

INTRODUCTION

This experiment is intended to serve as an example of how to carry out an organic

reaction. You will find a reaction which may appear as one line in a textbook actually

involves several steps, including the essential ones of isolating and purifying the product.

You should review the technique for taking a melting point and recrystallizing a

compound BEFORE COMING TO THE LABORATORY. The procedure is explained

in the Appendix I.

The carbonyl group of aldehydes and ketones may be converted to a hydroxyl group by a process known as reduction. Aldehydes may be reduced to primary alcohols, while

ketones yield secondary alcohols.

You will notice that the process of reduction involves the addition of a molecule of

hydrogen across the double bond of the carbonyl group.

The most general method of reducing compounds with carbon-oxygen double bonds is

reaction with lithium aluminum hydride. In this experiment, however, you will use

sodium borohydride to reduce a ketone (benzophenone) to an alcohol (benzhydrol).

Lithium aluminum hydride and sodium borohydride will both reduce aldehydes and

ketones to alcohols; the main difference between the two reagents is that lithium

aluminium hydride is a much more reactive reducing agent than sodium borohydride,

which makes it more difficult to handle safely. For example, lithium aluminium hydride

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reacts explosively with water and readily decomposes in moist air, whereas with sodium

borohydride the hydrolysis in water is sufficiently slow at room temperature to allow its

use as a reducing agent in an aqueous medium.

Very many organic compounds are insoluable in water, so it is necessary to use ethanol

as a co-solvent in sodium borohydride reductions. However, sodium borohydride reacts

rapidly with ethanol and it is therefore necessary to use a large excess of sodium

borohydride to overcome the effect of this solvolysis and to ensure that enough is present

to reduce the carbonyl group.

Theoretically, one mole of sodium borohydride will reduce four moles of benzophenone

to yield a borate ester.

4C 6H5COC 6H5 + NaBH 4 Na[(C 6H5)2CHO] 4B (3)

This borate ester may be hydrolyzed with aqueous sodium hydroxide to yield benzhydrol.

The sodium hydroxide acts as a catalyst for the hydrolysis.

Na[(C 6H5)2CHO] 4B + 4H 2O 4C 6H5-CH.C 6H5 + NaB(OH) 4 (4)

|

OH

The product benzhydrol is soluble in the ethanol-water mixture which was used for the

reaction but is insoluble in water. Thus, if the reaction mixture is diluted with cold water

the product will precipitate. Sodium borate remains in solution since it is a salt and very

soluble in water.

PROCEDURE:

In a 100 ml Erlenmeyer flask, dissolve 6.0 g of benzophenone in 50 ml of ethanol. In a 50

ml beaker dissolve 0.6 g of sodium borohydride in 25 drops of distilled water, and using a

medicine dropper add this solution drop-wise, with swirling, to the solution of

benzophenone. Swirl the mixture from time to time for 15 minutes. Add 4 ml of a 6N

aqueous sodium hydroxide solution and boil the reaction mixture, using a boiling chip, on

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a steam bath for 10 minutes. Pour the reaction mixture into 100 ml of cold water and ice

(100 ml total) and

collect the resulting precipitate of benzhydrol on a Buchner funnel. Dry the crude product

for 15 min. at 60C under suction, weigh it, and then recrystallize from a minimum

volume of 95% ethanol (b.p. 78.2C).

Weigh your recrystallized product and determine the percentage yield of crude product

and of recrystallized product and the melting point of your pure benzhydrol product.

Submit a sample for grading.

Take an infrared spectrum of your starting material (benzophenone) and your purified

final product (benzhydrol). Discuss differences and point out characteristic absorption peaks.

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LABORATORY 4 - CATALYTIC HYDROGENATION OF SQUALENE (A

POLYUNSATURATED HYDROCARBON)

(1 LAB PERIOD)

I. INTRODUCTION

Hydrogenation is the general method of converting a carbon-carbon double bond or triple

bond ( -bonds) into a carbon-carbon single bond ( -bond). The energy of activation for

the reaction is very high. Therefore, a catalyst is needed to reduce this activation energy

and enable the reaction to proceed at room temperature.

Hydrogenation is frequently used in the food industry to convert unsaturated fats such as

soybean oil and cottonseed oil into saturated solids. This is done to increase the shelf-

life of oils by removing the oxidation-sensitive double bonds. Saturated oils (fats) are

solids having a consistency similar to that of lard. However, from the nutritional point of

view, saturated fats are less healthy because they are harder to break down and cause

deposition on the arterial wall; unsaturated oils, especially polyunsaturated oils, areconsidered to be healthier.

Table 2.1 lists the fatty acid content of several commonly consumed oil products.

Table 2.1 Approximate fatty acid content of some fats (percentages)

ACIDmelting point.

(oC)

BUTTER FAT

COTTONSEEDOIL

OLIVEOIL

PALMOIL

LINSEED

OILButyric, C 3H7COOH 3-4Caproic, C 5H11COOH 1-2Caprylic, C 7H15COOH 1-2Capric, C 9H19COOH 2-4Lauric, C 11H23COOH 3-5Myristic, C 13H27COOH 9-11 1-4 0.2Palmitic, C 18H31COOH62.9

22-30 20-23 7-15 35-45 5

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Stearic, C 17H35COOH69.9

7-15 1-3 1-4 1-8 4

Oleic, CH 3(CH 2)7CH=CH(CH 2)7COOH16

29-40 24-30 70-85 40-50 6-12

Linoleic, C 17H33COOH

-5

3-5 42-54 4-12 2-11 26-46

Linolenic,CH 3(CH 2)4CH=CHCH 2CH=CH(CH 2)7COOH

36-50

For the purpose of the following lab a polyunsaturated hydrocarbon, squalene, will be

hydrogenated in the presence of 10% palladium on carbon support as a catalyst.

Squalene is a naturally occurring polyunsaturated hydrocarbon. Whale oil is rich in

squalene. It is built from polyisoprene blocks. Note that isoprene (2-methyl-butadiene)

is the basic building block of several natural compounds, including cholesterol and

steroids. The multiple double bonds of squalene (6) will disappear due to the addition of

hydrogen, and IR analysis results will show an obvious distinction between the

hydrogenated (saturated), and unhydrogenated (unsaturated) squalene.

Squalene

CH 3

CH 3

CH 3 CH 3 CH 3

CH 3 CH 3

H 3 C

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Squalane

Figure 2.1. Squalene & Squalane

By knowing the stoichiometry of one hydrogen molecule reacting with each double bond,

hydrogenation can also be used as a quantitative tool to determine the number of double

bonds in an organic compound.

II. MATERIALS

squalene

hydrogen (already set up)

chloroform

catalyst (10% Pd on carbon support)

III. EQUIPMENT

Hydrogenation Apparatus as seen in Figure 2.2

H3

CCH 3

CH 3 CH 3 CH 3

CH 3 CH 3 CH 3

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IV. PROCEDURES

BE CAREFUL WITH HYDROGEN GAS. IT IS HIGHLY FLAMMABLE! Mixed

with oxygen in a 2:1 ratio it forms an explosive gas.

Before you start, study the apparatus and compare with the one in the notes. Stopcock A

is 3-way so gas can be allowed to fill different parts of the system. Also read the

introduction on GAS CYLINDERS found at the beginning of this manual.

The hydrogenation reaction takes place in a closed system made up of the gas burette

connected to the reaction flask. However, the system is full of air and this needs to be

exchanged with hydrogen before the reaction is started.

The hydrogen cylinder is equipped with a two-stage regulator. The high pressure gauge

(closer to the cylinder) shows the pressure in the cylinder when you open the main valve

on the cylinder.

The low pressure gauge (second stage) will show the pressure of the gas going to your

apparatus. Open the first stage to tank pressure and set the second stage to about 2.5

pounds per square inch pressure. DO NOT EXCEED 6 POUNDS/INCH 2 ON THE

SECOND STAGE. Open the needle valve which connects the cylinder to your apparatus.

The pressure on the low gauge may drop. Readjust it.

To clear air out of the system: first open stopcock B and turn stopcock A (3-way) so that

it connects the gas burette to the exhaust line. See Figure 4 of 2.2. Expel all air present in

the gas burette by holding the reservoir up until the oil pushes all the air out;

approximately 1cm below stopcock A. Then turn stopcock A (3-way) so that H 2 gas can

flow through the system and exit via the exhaust tube without entering the gas burette.

See Figure 2 of 2.2. Flush the system with hydrogen and shut off flow at the regulator

needle valve.

To prepare the gas burette with hydrogen ready for the reaction:

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Turn the three way stopcock A to the position which allows H 2 to enter the gas burette

See Figure 3 of 2.2. Carefully turn on the hydrogen flow and fill the burette with

hydrogen gas 5-6cm from the bottom of the burette.

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Figure 2.2 Hydrogenation apparatus

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Once the burette is full of hydrogen, turn stopcock A back to the bypass position (Figure

2 of 2.2).

To set up the reaction flask: pipette 1ml of squalene into 19 ml. Chloroform. Place 5 ml.

Of this mixture into the reaction flask along with a magnetic stirrer. Add about 80mg of

10% palladium on charcoal to the reaction flask. This is the catalyst.

Flush the flask with hydrogen for 2-3 minutes using the gas inlet. When flushing, be sure

to hold the glass stopper loosely to allow the hydrogen to enter the flask and the air to

leave out the sides.

Before starting the reaction record the volume of H 2 in the gas burette. This is done bymatching the levels of oil in the burette and the reservoir. Then move the reservoir to its

maximum height to exert a small pressure on the hydrogen in the closed system.

To start the reaction close the main valve on the H 2 cylinder. Place the gas inlet tube

snugly into the flask and turn the three-way stopcock A to connect the gas burette with

the reaction flask (see Figure 4 of 2.2). Stopcock C should also be open to allow

hydrogen into the reaction flask. Turn on the magnetic stirrer and let the reaction proceed

until there is no longer a change in H 2 volume (about one-half hour). Check the extent of

the reaction by matching the oil in the burette and reservoir. Record the amount of H 2

every 5 minutes.

During the reaction observe whether the flask is cooling or warming up.

Stop the stirrer when there is no longer a decrease in H 2 over a 5-10 minute period.

Match the oil level in the gas burette with that in the oil reservoir and record the final

volume of hydrogen and the room temperature. Close the stopcocks and remove the

reaction flask. By matching the oil levels before and after the reaction, the final volume

reading is obtained at a pressure of 1 atm.

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Release the pressure from the apparatus through the exhaust line by opening stopcocks A

and B and loosening the membrane valve (second stage) all the way. Both gauges should

read zero psig.

Filter off the catalyst using vacuum filter apparatus and buchner funnel. Place the

catalyst in the vessel for Pd residues.

V. INFRARED ANALYSIS

For the theory of infrared analysis refer to the Appendix.

Procedure:1. Rinse IR cell with CHCl 3 and run CHCl 3 sample, scanning from 300 to 700.

2. Run sample of original unsaturated squalene and CHCl 3.

3. Run sample of hydrogenated squalene and CHCl 3.

Compare differences in peaks around area where double bonds are detected. Note, this

will only provide you with a qualitative analysis, not a quantitative analysis.

Make photocopies of the three IR charts for each member of the lab group and submit

them along with the formal lab report. Remember to properly label the figures and

clearly indicate the observed changes in the peaks.

VI. PRE-LAB QUESTIONS

To be completed before starting the laboratory please check with T.A. for proper

calculations

1) Write down the structure of isoprene and squalene. List the physical properties of

squalene ( mol. wt., density, boiling point, melting point) and write the stochiometric

equation for the hydrogenation of squalene.

2) Calculate the theoretical volume of H 2 required to completely hydrogenate your

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squalene sample (hint: use ideal gas law).

VII. SUMMARY OF REQUIREMENTS FOR LABORATORY REPORT

1) From the volume of hydrogen used, calculate the number of grams and moles of hydrogen consumed in the reaction.

2) Given that squalene has a density of 0.858 g/cm 3 at 25 0C, how many grams of hydrogen were taken up per 100g of squalene? How many moles of H 2 are taken up

by 1 mole of squalene? (Use the molar weight, MW = 410.73gmol -1 of squalene for

your calculations.)

3) How many moles of hydrogen reacted per mole of palladium present?Is hydrogenation exothermic or endothermic and why?

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LABORATORY 5 EPOXIDATION OF 1-TMP AND IODINE TITRATION

(2 LAB PERIODS)

I. INTRODUCTION AND THEORY

Compounds containing the three-membered ring CHCH

O

, are called

epoxides. Epoxides are ethers with unusual properties due to the strained ring structure

present. One method to prepare them is to use peroxybenzoic acid to oxidize alkenes or

double bonds in chloroform, dichloromethane or ether as solvent. Once prepared, the

three-membered ring easily undergoes acid- and base-catalyzed cleavage. An example of

the mechanism and orientation during the cleavage of isobutylene oxide, a substituted

epoxide is shown:

H3C C CH 2

CH 3

O

+ H3C C CH 2OHCH 3

OH

H3C C CH 2

CH 3

O

+ CH 3 O HCH 3ONa

H+

H3C C CH 2

CH 3

OH

OCH 3

Acid-catalyzed cleavage:

Base-catalyzed cleavage:

HOH

The following experiment makes use of the fact that each double bond reacts with one

mole of peroxyacid to form the epoxide ring. The reaction for 2,4,4-trimethylpentene-1

(TMP-1) is shown:

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The mol% unsaturation can be calculated by back-titration of any unreacted peracid. This

is done by reacting the leftover (unreacted) acid with potassium iodide, which will release

I2 exactly equivalent to 2 mols of peroxiacid:

The liberated I 2 is then titrated with Na 2S2O3. The reaction for the titration is:

I2 + 2 Na 2S2O3 Na 2S4O6 + 2 NaI (3)

From reaction (3) it is clear that 2 mol Na 2S2O3 is equivalent with one mol I 2 (1N

Na 2S2O3 = 0.5M Na 2S2O3)

Iodine titration is used very often in industry for double bond titration; it is also used for water analysis at the ppm level (Carl-Fischer titration).

H 3 CC

CH 3H 3 C

CH 2

C

CH 2

CH 3

+ ClC O

OHO

H 3 CC

CH 3H 3C

CH 2

C

H 2 C

CH 3

O

+ ClC

OHO

1-TMP3-Chloroperoxybenzoic acid

1-TM POxide 3-Chlorobenzoic acid

ClC O

OHO

+2KICl

C OKO

+ I2 + +H2O 1/2O 22 2

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II. MATERIALS

3-Chloroperoxybenzoic acid, (CPBA)

sodium phosphate

potassium dihydrogen phosphate

dichloromethane

glacial acetic acid

10w% potassium iodide

0.1N sodiumthiosulfate

starch indicator

water bottle with distilled water

III. EQUIPMENT

3, 1L beakers

stirring plate and magnetic stirrers

vacuum oven or desiccators

100ml volumetric flask

3, 250ml Erlenmeyer flasks

1ml, 10ml pipettes

timer

4, 5ml and 1, 10ml graduated cylinder

watch-glasses

burette

nitrile gloves

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IV. PROCEDURES

PART A (WEEK 1)

A) PURIFICATION OF PERACID:

During storage 3-Chloroperoxybenzoic acid decomposes to give a mixture of the peroxy

(a) and the carboxylic (b)

acids. Therefore, purification

is needed to remove the

carboxylic acid by a buffer

which selectively dissolves

the acid but leaves the desired peroxyacid or peracid insoluble.

Step 1: Prepare the buffer solution

Dissolve 67.1g of sodium phosphate (Na 2HPO 4.7H 2O) in 500ml of distilled water. Do the

same with 34g of potassium dihydrogen phosphate (KH 2PO 4) in a separate beaker. Once

the solids are completely dissolved mix the two solutions.

Step 2: Washing of the peracid

Take 50g of raw ( 50% purity) 3-Chloroperoxybenzoic acid (CPBA) and place it in a

large beaker. Add about 200ml of buffer and stir it well using a stirring rod. Let the solid

settle down and decant the liquid. Repeat 4 more times. (The settling of the solid takes

time so set up the Buchner funnel). Next, wash the peracid 3 times the same way with

distilled water. The last 2 washes should be done on a Buchner funnel to filter the solid

(see discussion on Buchner funnel at the beginning of the lab notes).

Cl

C O

O

OH

Cl

C OH

O

3-Chloroperoxybenzoic acid and 3-Chlorobenzoic acid(a) (b)

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Step 3: Drying of the peracid

Weigh an empty beaker, sufficient in size to hold all of your peroxyacid. Transfer the

peroxyacid from the Buchner funnel into the beaker. This is the pure peroxyacid, which

should be dried. Label the beaker with the name of compound, your name, group number

and date. Place in a desiccator. The following week the peracid should be dry and ready

to use. Measure the amount recovered and do a %yield calculation.

PART B (WEEK 2)

B) EPOXIDATION OF 1-TMP AND IODINE TITRATION

FOR YOUR PROTECTION PLEASE WEAR NITRILE GLOVES (BLUE) FOR

STEP 4/a OF THIS EXPERIMENT. The dichloromethane used in this experiment

dissolves the latex gloves and is harmful to your skin.

Step 4a) Preparation of 0.1M CPBA

In a weighing boat measure out the amount needed to make 50ml of 0.1M CPBA from

the one that you made last week. Record the exact weight used to 4 decimal point

accuracy. UNDER A FUMEHOOD transfer this amount into a clean, dry, 50ml

volumetric flask using a funnel. Rinse the boat and the funnel with dichloromethane

(CH 2Cl2), and add some more CH 2Cl2 to dissolve the solid. Wait until complete

dissolution and fill up the volumetric flask to the mark. Calculate the exact molarity of

your peracid solution and record it in your notebook. Stopper the flask, label it, wrap it in

aluminum foil and label it on the outside again. Peroxyacid is heat and light sensitive and

every precaution should be taken to prevent it from decomposing.

Step 4b) Epoxidation and iodine titration

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The TMP-1 is epoxidized by reacting it with excess CPBA in a dichloromethane solution.

After 10 minutes reaction time the amount of leftover peracid is determined by reacting it

with excess KI and backtitrating the liberated I 2 with sodium thiosulfate (Na 2S2O3). By

knowing the stoichiometry of each reaction, the extent of the epoxidation can be

determined.

2 mols of peracid releases 1 mol of I 2. 1 mol of I 2 reacts with 2 mols of Na 2S2O3. Thus, 1

mol of peracid will be equivalent to 1 mol of Na 2S2O3. The Na 2S2O3 is normalized

against I 2 so 1 mol I 2 is equivalent to 2 mols Na 2S2O3. Therefore, the normality of 1 M

Na 2S2O3 = 2 N. Also, 10ml of 1 M m-CPBA will be equivalent to 10ml of 1 M Na 2S2O3

or 20ml of 1 N Na 2S2O3. (See reaction equations in the INTRODUCTION section).

Step 4b.1) Blank titration

Since one can never make an exact 1 M solution, the exact amount of the peracid in the

0.1 M solution made in Step 4 a will be determined by a blank titration. Thus, 10ml of

peracid solution is reacted by excess KI, and the liberated I 2 is backtitrated by Na 2S2O3. If

the peracid solution were perfect, 10ml of peracid should be equivalent to 20ml of 0.1 N

sodium

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