Uv Spectroscopy

Journal of Supercritical Fluids 15 (1999) 109–116

Partition coefficients of aromatic organic substances in two-phasemixtures of water and carbon dioxide at pressures from 8 to

30 MPa and at temperatures of 313 to 333 K. Part II

Klaus-D. Wagner, Karlheinz Brudi, Nicolaus Dahmen *, Helmut SchmiederForschungszentrum Karlsruhe, Institut fur Technische Chemie, CPV, PO Box 3640, D-76021 Karlsruhe, Germany

Received 10 August 1998; received in revised form 24 December 1998; accepted 28 December 1998

Abstract

In the two phase system of water and supercritical carbon dioxide, the partitioning behavior of two single solutes,aniline and benzaldehyde, was measured at temperatures of 313, 323 and 333 K and pressures up to 30 MPa using arecirculation view cell apparatus. Samples were taken from both phases and analyzed either by UV-spectroscopy orgas chromatography. The partition coefficient in this case is defined as the ratio of molar fractions of a substance inthe carbon dioxide-rich phase and the aqueous phase in equilibrium. Partition coefficients between 0.21 and 3.03 werefound for aniline and 2.5 up to 62.9 for benzaldehyde. In addition to the single solute measurements, the distributionbehavior of an aqueous solution of phenol, benzyl alcohol, cyclohexanol and 2-hexanone was examined at 323 K.While the alcohols were entrained in the fluid phase, the other compounds were retained in the aqueous phase.Analogous to high pressure binary solid fluid phase equilibria, an enhancement factor is introduced to describepartitioning equilibria. Differences in the distribution behavior of single solutes are discussed in terms of the enthalpyof hydration. © 1999 Elsevier Science B.V. All rights reserved.

Keywords: Enhancement factor; Enthalpy of hydration; Partition coefficient; Phase equilibria; Supercritical carbon dioxide

Daqs H enthalpy of solubilizationNomenclatureK partition coefficientKc partition coefficient based on concentrationsa,b,A∞ constants at constant temperatureKx partition coefficient based on molar fractionsc

iconcentration of component i

p pressureE,E∞ enhancement factorhi

Henry constant of solute i pref reference pressure (1 Pa)Daql H molar enthalpy of mixing p*v vapor pressure of the pure substanceDgaqH enthalpy of hydration p

ipartial vapor pressure of solute i above an aqueous

DgsH enthalpy of sublimation solutionDgl H enthalpy of vaporization R gas constant

T temperaturexji

molar fraction of component i in phase j* Corresponding author. Tel.: +49-7247-82-2596;r density of pure carbon dioxidefax: +49-7247-82-2244.

E-mail address: [email protected] (N. Dahmen) rref reference density (700 kg m−3)

0896-8446/99/$ – see front matter © 1999 Elsevier Science B.V. All rights reserved.PII: S0896-8446 ( 99 ) 00004-2

110 K.-D. Wagner et al. / Journal of Supercritical Fluids 15 (1999) 109–116

1. Introduction ous phase causes no problems, as the componentsto be determined remain in solution. In contrast,the sampling process in the fluid phase causes theFor the proper design of a separation process,

in which organic substances are to be removed organic material to precipitate as the carbon diox-ide expands. This material is completely washedfrom an aqueous solution by supercritical carbon

dioxide, the relevant phase equilibria have to be into a sampling vial by water, and the samples areanalyzed afterwards.known accurately. Phase equilibrium in context

with countercurrent extraction is often charac- In addition to single solute measurements, thedistribution behavior of an aqueous solution ofterized by partition coefficients, K, describing the

distribution of solutes between the two immiscible 1 wt.% phenol, 1 wt.% benzyl alcohol, 0.5 wt.%cyclohexanol and 3 wt.% 2-hexanone at 323 K wasphases. In continuation of previous measurements

of the partitioning behavior of monofunctional examined. The analysis was conducted byUV-spectroscopy in the case of aniline. SPMEaromatic compounds [1], we now report on two

further substances, aniline and benzaldehyde. In (solid phase micro extraction) and gas chromatog-raphy (GC) were used to determine the composi-the experimental range studied here, the mutual

miscibility of water and carbon dioxide is very tion of the mixture components. SPME as apretreatment method allows the analysis of aque-limited. Due to the compressibility of the fluid

carbon dioxide phase, K is strongly dependent on ous samples directly by GC. To check theagreement of both methods, benzaldehyde wastemperature and pressure. In addition, the parti-

tioning of a substance is affected by the presence measured independently in both ways (Table 1).of other solutes. Salts are especially likely toincrease K [2], but other organics present in thesolution can also influence partition coefficients.

3. Results and discussionIn this context, the partitioning behavior of anaqueous solution containing four organic com-

The partition coefficient is defined as the ratiopounds was investigated.of concentrations, c

i, Eq. (1a) or the ratio of molar

fractions, xi, Eq. (1b) of the substance, i, in both

phases:2. Experimental

The measurement of the partition coefficients in Kc=cCO

2icH2Oi

(1a)two-phase mixtures was performed using an ana-lytical method with a recirculation view cell appa-ratus [1], which is placed in a liquid bath whose Kx=

xCO2i

xH2Oi

(1b)temperature is kept constant within ±0.1 K. Thehigh pressure cell is filled by half with an aqueous

While Kc is the direct result of the analysis, Kxsolution of the organic substances. At the requiredwas calculated using the density data of pure watertemperature, CO2 is compressed in the cell by aand carbon dioxide at the distinct temperaturespneumatic pump until the final pressure is reached.and pressures [1] from reference equations.The temperature is measured by a Pt-100 resistance

thermometer in the wall of the cell, while pressureis measured in the autoclave by a pressure trans- 3.1. Partitioning of single solutesducer equipped with a front membrane. Thecarbon dioxide phase is recirculated by a gear Distribution behavior is mainly determined by

the solubility of the solute in the CO2 phase.pump until equilibrium is attained. Samples weretaken from both phases by means of six-way valves Regarding the binary solute–carbon dioxide sys-

tems with liquids of low volatility, often a type IIIwith sampling volumes of 250 ml for the aqueousand 100 ml for the CO2-phase. Sampling the aque- phase diagram according to the classification of

111K.-D. Wagner et al. / Journal of Supercritical Fluids 15 (1999) 109–116

Table 1Fluid phase concentrations and partition coefficients of aniline and benzaldehyde

313 K 323 K 333 K

p (MPa) xCO2i

(10−3) Kx p (MPa) xCO2i

(10−3) Kx p (MPa) xCO2i

(10−3) Kx

Aniline8.23 1.09 0.36 7.97 0.45 0.21 8.22 0.73 0.23

10.05 2.32 1.13 10.31 0.94 1.29 10.39 1.30 0.4512.08 2.80 1.82 15.10 2.07 1.90 12.42 2.50 1.0915.21 2.79 2.00 19.41 2.57 2.03 15.15 2.95 1.7020.09 3.16 2.23 24.98 2.95 2.46 20.22 3.00 2.3924.91 3.01 2.38 29.83 3.09 2.84 25.56 3.05 2.7330.26 2.72 2.42 30.26 3.02 3.03

Benzaldehyde, GC-SPME detectiona8.47 6.5 7.5 10.50 10.4 17.7 10.65 10.3 9.89.93 15.5 27.6 15.31 11.7 33.4 15.55 10.7 25.1

15.15 14.1 43.6 19.81 10.8 40.5 20.71 12.7 35.620.82 12.0 47.0 25.37 11.5 49.6 25.09 23.2 40.725.08 13.1 55.3 30.36 12.3 46.530.14 11.6 62.2

Benzaldehyde, UV-Vis detectiona8.07 1.43 5.6 8.34 0.43 3.2 8.17 0.38 2.5

10.13 1.29 29.9 10.53 0.85 13.5 10.02 1.30 5.212.11 1.12 36.4 12.56 0.98 23.9 12.18 1.50 14.115.72 1.05 45.9 15.41 0.99 33.2 15.14 1.27 25.720.13 0.96 51.4 20.71 1.01 40.2 20.04 1.03 33.825.41 0.92 56.4 25.65 1.04 43.8 24.74 0.95 40.630.26 0.84 62.9 30.43 1.06 46.9 29.93 0.88 45.0

a Molar fractions of benzaldehyde vary between both detection methods because of different initial concentrations.

van Konynenburg and Scott is found. If the solutes tion coefficient increases at higher pressures. Thecontrary effect of rising temperature on vaporare solid, the critical line in many cases is

interrupted by a solid phase equilibrium (Fig. 1). pressure and density often leads to the intersectionof isotherms.Near the critical end points, the most pronounced

changes in solubility occur [3]. As the critical end Fig. 2 shows the experimental results of thedistribution measurements with aniline at 313, 323point (CE) and the lower critical end point

(LCEP), respectively, usually is not far from the and 333 K [4]. The partition coefficients obtainedranged from 0.21 and 3.03. The partitioning obeyscritical point of pure solvent (CP1), the strongest

increase in the solubility, x, as well as in the a phase behavior as discussed above. In Fig. 3, theisotherms of benzaldehyde at the three temper-partition coefficient, K, is observed near the critical

point of CO2 in most cases. The nearer the temperatures are plotted versus pressure [4]. The parti-tioning coefficient reaches values up to 62.9.ature approaches to the critical end points, the

more steep is the change in x and K. Similar to Intersection of the isotherms, as observed com-monly in other systems, was not determined in thethe density behavior of pure carbon dioxide, which

determines the dissolving power of the solvent, the experimental pressure range. The determination ofthe solute concentration by the two analyticalincrease becomes smaller with rising pressure. With

increasing temperature, leading to a higher vapor methods show reasonably good agreement of GCwith SPME and UV-spectroscopy.pressure of the solute, the solubility and the parti-


Fig. 1. Typical p,T-projections of binary solute–CO2 systems containing liquids or solids of low volatility.

Fig. 2. Partition coefficients of aniline at temperatures of 313,323 and 333 K and pressures from 8 to 30 MPa.

Fig. 3. Partition coefficients of benzaldehyde at temperaturesof 313, 323 and 333 K and pressures from 8 to 30 MPa; determi-

3.2. Partitioning of mixtures nation of the solute concentration by GC with SPME andUV/Vis-spectroscopy.

In comparison with single solute measurements,it was found that the alcoholic components withtheir lower single-solute partition coefficients are by Knopf [5] on the basis of binary solute–solute

interactions and the relative volatilities of theenhanced, and 2-hexanone, possessing higher K-values, remains unchanged or is even retained in single solutes.the aqueous solution. Additionally, the curvatureof the isotherms is changed in a way that the 3.3. Interpretation analogous to solid–fluid phase

equilibriapartition coefficients of the mixtures show a slightmaximum. These effects are presented in Table 2.Data for phenol, 2-hexanone and benzaldehyde in In the following, a correlation is developed to

describe the partitioning behavior in terms ofa logarithmic scale are displayed in Fig. 4. Theentrainment of the alcohols can be explained quali- enthalpy of hydration. In the context of high

pressure, solid–fluid phase equilibria, the enhance-tatively by cosolubility phenomena, as discussed


Table 2Fluid phase concentrations and partition coefficients of a mix-ture containing phenol, benzyl alcohol, cyclohexanol and2-hexanone at 323 K

p (MPa) xCO2i

(10−3) Kx

2-Hexanone8.0 13.67 94.68

10.2 19.37 89.5515.3 23.81 103.2720.5 19.69 101.4025.5 15.49 98.0830.0 17.76 66.84

Cyclohexanol8.0 0.15 0.85

10.2 0.75 3.4915.3 0.95 4.0620.5 0.83 4.1325.5 0.75 4.16 Fig. 4. Partitioning of phenol, 2-hexanone and benzaldehyde in30.0 0.82 3.27 a multicomponent mixture (solid symbols) in comparison with

single solute measurements (open symbols) at 323 K.Phenol8.1 2.45 2.06

10.3 3.20 2.1815.4 4.15 2.83 above an aqueous solution p

iat the same temper-

20.6 3.86 2.82 ature:25.6 3.49 2.7530.1 3.59 2.19

E∞=xCO

2ip

pi

=xCO

2ip

xH2iOh

i

=Kxp

hi

(3)Benzyl alcohol8.1 0.14 0.26

On the assumption of a dilute solution, pi

can10.3 1.21 1.72be expressed by Henry’s law. xH

2Oi

is the molar15.4 1.55 2.1820.6 1.49 2.29 fraction of the solute in the aqueous phase and h

i25.6 1.43 2.44 the Henry constant. With Eq. (1b), the partition30.1 1.39 1.73 coefficient Kx is inserted into Eq. (3). Just as in

high pressure, binary solid–fluid phase equilibria,the logarithm of E∞ can be related to a linearfunction of density r of the pure carbon dioxide

ment factor, E, is the ratio of the partial vapor [7]:pressure of the solute in the supercritical phase to

ln(E∞)=a+br (4)the vapor pressure of the pure solute p*n

at thesame temperature [6 ]: with temperature dependent constants a and b. As

hi

of low volatile solutes is as seldom known asE=

xCO2,S

ip

p*v

(2) p*n

, hi

is substituted in a first step by a referencepressure pref, for which 1 Pa is used in the followingcalculations. In a second step, it is necessary towhere xCO

2,S

iis the saturation molar fraction of

solute at pressure p. Analogous to binary phase introduce a reference density rref=700 kg m−3 [7].This leads to the following equation:equilibria, the enhancement factor in the case of

partitioning E∞, is defined as the ratio of the partialln(K

xp/pref)=[a+ln(h

i/pref)+brref ]vapor pressure of the solute in the supercritical

phase to the partial vapor pressure of the solute +b(r−rref)=A∞+b(r−rref) (5)


Fig. 6. Plot of A∞-values of phenol versus temperature, 1/T.Fig. 5. Plot of ln(Kxp/pref) of phenol versus density ( p−pref) attemperatures of 308, 313, 323 and 333 K.

linear function down to values of (r−rref)=−100 kg m−3. The interpolation lines in Figs. 2Analogous to the enthalpy of sublimation or

vaporization, respectively, a plot of A∞ versus 1/T and 3 were calculated using the correspondinglinear correlations of ln(Kxp/pref). In Fig. 6, theshould result in a linear function with a slope of

−DgaqH/R, with DgaqH being the enthalpy of hydra- values of A∞ are plotted versus 1/T. From the slopeof the resulting linear correlation, an enthalpy oftion [8].

In Fig. 5, a plot of ln(Kxp/pref) versus (r−rref) hydration of 35±2 kJ mol−1 is obtained in thecase of phenol. The enthalpies of hydration, offor the experimental data of phenol [1,4] is shown.

The data points correlate adequately with this mixing and of phase transition for phenol and the

Table 3Enthalpy of hydration, DHhydr, from partitioning between CO2 and H2O and enthalpy of sublimation/vaporization, DHsub/vap, fromsolubility in CO2 in comparison with literature data

Substance DgaqHa DgaqH at 298 K Daql H at 298 K Dgl Hb Dgl H at 298 K

2-Hexanone 23±6 42.22±0.08 [9]Cyclohexanone 24±4 55.19±1.13c −10.3±0.5 [10] 44.89±0.63 [11]Aniline 38±2 53.95±0.16c 1.88±0.13 [12] 55.83±0.03 [13]Benzyl alcohol 45±6 59.75±0.42c 0.54 [14] 50±4 [15] 60.29±0.42 [16 ]Benzaldehyde 24±2 35±5 [17,18] 49.80±0.80 [19]

DgaqHa DgaqH at 298 K Daql H DgsHb DgsH at 298 KPhenol 35±2 56.94±0.21 [20] 1.46d 71±7 [21,22] 68.66± 0.50 [23]

DgaqHa DgaqH at 298 K Daqs H DgsHb DgsH at 298 KBenzoic acid 22±3 75±4 [24–26 ] 89.30±0.90 [27]Vanillin 31±1 73 [28] 90.2eCaffeine 36±7 74±2 [29] 105.10 ±0.70 [30]

a From partition coefficients between water and carbon dioxide.b From solubility in carbon dioxide.c Calculated as the difference DgaqH=Dgl H−Daql H.dCalculated as the difference Daql H=Daqs H−DlsH=12.97 [31]-11.51 kJ mol−1 [32].eThe observed value DgsH=88.70 kJ mol−1 [33] was extrapolated to 298.15 K using the ‘Sidgwick correction’ [34].


other organic substances examined in Ref. [1] and correlated and discussed in terms of the enthalpyof hydration, resulting in an adequate agreementthis paper are shown in Table 3. The values of

DgaqH obtained from partitioning coefficients in with data reported in the literature regarding thesimplicity of the estimate.this way are compared with values from the litera-

ture. These values are calculated from the enthalpyof sublimation or vaporization minus the enthalpyof solution or mixing for each compound, respec-

Referencestively. The same comparison was done for thesolubility data of the substances in carbon dioxide.

[1] K. Brudi, N. Dahmen, H. Schmieder, Partition coefficientsFor 2-hexanone, cyclohexanone, aniline, benzylof organic substances in two-phase mixtures of water and

alcohol, benzaldehyde and phenol, the values of carbon dioxide at pressures of 8 to 30 MPa and temper-DgsH or Dgl H, respectively, as well as of DgaqH from atures of 313 to 333 K, J. Supercrit. Fluids 9 (1997) 146.

[2] K.-D. Wagner, K. Brudi, N. Dahmen, H. Schmieder,the literature and from the experiments show theInfluence of pressure, temperature, and salt effects on thesame relative order within the errors. For thepartitioning of phenol in two-phase mixtures of water andinvestigated substances, the values for Dgs,lH deter-supercritical carbon dioxide, in: Proceedings of the Fourth

mined from solubility data lie significantly below International Symposium on Supercritical Fluids, vol. B,the values from the literature. This is obviously 1997, p. 719.

[3] M. McHugh, V. Krukonis, Supercritical Fluid Extraction,transferred to the values of DgaqH from partitionButterworth, Stoneham, 1986.experiments, which lie below the literature data

[4] K. Brudi, Bestimmung von Verteilungskoeffizienten intoo. For substances of lower volatility, the deter-ternaren Mischsystemen mit Wasser, uberkritischem

mined DgaqH-values show larger deviations from Kohlendioxid und organischen Komponenten, Dissertationthe literature or expected data. University of Karlsruhe, Germany, VDI Fortschritt-

Berichte Reihe 3, 1997, no. 505.In the above discussion, effects of composition,[5] S. Gupta, D. Ghonasge, K.M. Dooley, F.C. Knopf,association and temperature are not taken into

Supercritical carbon dioxide extraction of a phenolic mix-account. While literature enthalpy data was mea-ture from an aqueous waste stream, J. Supercrit. Fluids 4

sured at 298 K, the solubility data covers a different (1991) 181.temperature range for each substance. As partition [6 ] K. Johnston, D. Peck, S. Kim, Modeling supercritical mix-

tures: how predictive is it?, Ind. Engng Chem. Res. 28data, except for phenol, was measured at(1989) 1115.313–333 K, the resulting enthalpy of hydration

[7] K.D. Bartle, A.A. Clifford, S.A. Jafar, G.F. Shilstone,refers to 323 K. Nevertheless, it is possible toSolubilities of solids and liquids of low volatility in supercrit-

obtain the same relative order of enthalpies from ical carbon dioxide, J. Phys. Chem. Ref. Data 20 (1991) 713.the partition experiments compared with the litera- [8] G. Kortum, H. Lachmann, Einfuhrung in die chemische

Thermodynamik, Verlag Chemie, Weinheim, 1981.ture data. In addition, the introduced correlation[9] D. Harrop, A.J. Head, G.B. Lewis, Thermodynamic proper-of the partition coefficients provides a simple

ties of organic oxygen compounds. 22. Enthalpies of com-method for interpolations in pressure andbustion of some aliphatic ketones, J. Chem. Thermodyn. 2

temperature. (1970) 203.[10] V.P. Belousov, E.P. Sokolova, Heats of mixing of liquids.

IV. Heats of mixing in acetone–water, ethyl ketone–waterand cyclohexanone–water, Ser. Fiz. Khim. 3 (1966) 90.4. Conclusion

[11] G. Wolf, 143. Thermochemische Untersuchungen ancyclischen Ketonen, Helv. Chim. Acta 55 (1972) 1446.

In completion of previous results on single solute [12] W. O’Hara, H. Ko, M. Ackermann, L. Hepler,measurements, the partition coefficients of aniline Thermodynamics of ionization of aqueous anilinium ion,

J. Phys. Chem. 71 (1967) 3107.and benzaldehyde were determined. Regarding the[13] K. Kusano, I. Wadso, Enthalpy of vaporization of somemulticomponent mixture of phenol, benzyl alco-

organic substances at 25.0°C and test of calorimeter, Bull.hol, cyclohexanol and 2-hexanone, it was foundChem. Soc. Jpn 44 (1971) 1705.

that Kx of the alcohols is increased possibly by [14] C. Krishnan, H. Friedman, Solvation enthalpies of variousco-solubility of the 2-hexanone. The experimental nonelectrolytes in water, propylene carbonate and

dimethyl sulfoxide, J. Phys. Chem. 73 (1969) 1572.results of the single solute measurements were


[15] D. Walter, G. Maurer, High pressure vapor–liquid Preparation and physical properties of pure phenol, cresolsand xylenols, J. Chem. Soc. (1960) 5246.equilibria for CO2+benzonitril, CO2+benzyl alcohol,

[24] W. Schmitt, R. Reid, Solubility of monofunctional organicCO2+2-tert-butylphenol, CO2+methoxybenzene andsolids in chemically diverse fluids, J. Chem. Engng DataCO2+1,2,3,4-tetrahydronaphtalene at temperatures31 (1986) 204.between 313 and 393 K and pressures up to 20 MPa,

[25] J. Dobbs, J. Wong, R. Lahiere, K. Johnston, ModificationJ. Chem. Engng Data 38 (1993) 247.of supercritical fluid phase behavior using polar solvents,[16 ] J. Pedley, R. Naylor, S. Kirby, Thermochemical Data ofInd. Engng Chem. Res. 26 (1987) 56.Organic Compounds, Chapman and Hall, New York,

[26 ] R. Kurnik, S. Holla, R. Reid, Solubility of solids in super-1986.critical carbon dioxide and ethylene, J. Chem. Engng Data[17] D. Walther, G. Maurer, High pressure vapour–liquid equi-26 (1981) 47.libria in binary mixtures of carbon dioxide and benzalde-

[27] M.A.V. Ribero da Silva, M.J.S. Monte, The construction,hyde, bromobenzene, chlorobenzene, 1,2-dichlorobenzenetesting and use of a new Knudsen effusion apparatus,and 2-chloro-1-methylbenzene at temperatures betweenThermochim. Acta 171 (1990) 169.313 and 393 K and pressures up to 22 MPa, Ber.

[28] A. Wells, R. Chaplin, N. Foster, Solubility of phenylaceticBunsenges. Phys. Chem. 96 (1992) 981.acid and vanillan in supercritical carbon dioxide,[18] C. Kim, B. Angela, P. Vimalchand, M. Donohue, HighJ. Supercrit. Fluids 3 (1990) 8.

pressure binary phase equilibria of aromatic hydrocarbons[29] H. Ebeling, E. Franck, Spectroscopic determination of

with CO2 and C2H6, J. Chem. Engng Data 34 (1989) 391.caffeine solubility in supercritical carbon dioxide, Ber.

[19] N. Lebedeva, Y. Katin, Heats of combustion of certain Bunsenges. Phys. Chem. 88 (1984) 862.monosubstituted benzenes, Russ. J. Phys. Chem. (Engl. [30] M. Kaminski, W. Zielenkiewicz, Vapor pressure and heatTrans.) 46 (1972) 1088. of sublimation of caffeine, Calorim. Anal. Therm. 16

[20] G.H. Parsons, C.H. Rochester, C.E.C. Wood, Effect of (1985) 281.4-substitution on the thermodynamics of hydration of [31] L. Fernandez, L. Hepler, Heats and entropies of ionizationphenol and the phenoxide anion, J. Chem. Soc. (B) of phenol and some substituted phenols, J. Am. Chem.(1971) 533. Soc. 81 (1959) 1783.

[21] R.A. Van Leer, M.E. Paulaitis, Solubilities of phenol and [32] R.J.L. Andon, J.F. Counsell, E.F.G. Herington, J.F.chlorinated phenols in supercritical carbon dioxide, Martin, Thermodynamic properties of organic oxygenJ. Chem. Engng Data 25 (1980) 257. compounds, Trans. Faraday Soc. 59 (1963) 830.

[22] E. Yu, M. Zhu, Z. Fang, Solubility of phenol in subcritical [33] V. Serpinskii, S. Voitkevich, N. Lyuboshits, Determinationand supercritical carbon dioxide, J. Chem. Ind. Engng of the vapor pressures of several fragrant substances, Zh.(China) Huagong Xuebao 41 (1990) 81. Fiz. Khim. 27 (1953) 1032.

[23] R.J.L. Andon, D.P. Biddiscombe, J.D. Cox, R. Handley, [34] J.S. Chickos, D.G. Hesse, S.Y. Panshin, D.W. Rogers, M.D. Harrop, E.F.G. Herington, J.F. Martin, Thermo- Saunders, P.M. Uffer, J.F. Liebman, The strain energy of

cyclotetradecane is small, J. Org. Chem. 57 (1992) 1897.dynamic properties of organic oxygen compounds. Part I.

Uv Spectroscopy

Documents

Transcript of Uv Spectroscopy