Separating Mixtures of Organic Compounds
Transcript of Separating Mixtures of Organic Compounds
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Separating Mixtures of OrganicCompounds Crude oil is a
mixture of manydifferent compounds
Crude oil cannot beused until itscomponents areseparated
Separation methods can bephysical or chemical Fractional
distillation is aphysical method
It separates amixture on the basisof boiling points
Oil refineries use atower to do this
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Crude oil enters thebottom of the towerand is heated until itvaporizes
The temperature ishighest at thebottom of the tower
The lower the boilingpoint of acomponent thehigher up in thetower it will go
As fractions cool totheir boiling pointthey condense andare collected
Solvent extraction is used to purify theresidue of fractional distillation
The residue contains hydrocarbons witha high molar mass
Solvents are mixed with this residue todissolve impurities
Chemical Refining
The fractions can also be chemicallyrefined to make them more useful
Two processes:– Cracking
– Reforming
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Cracking
Heating a hydrocarbon in the absence of air– Causes carbon carbon bonds to break
– Takes long chain hydrocarbons and breaks theminto smaller ones
Reforming
Uses heat, high pressure and catalysts toconvert straight chain alkanes into branchedand cyclic alkanes and aromatics (which havebetter burning properties)
Assignment
Page 582 Questions 1-8 (you may have toread Section 14.4 in your textbook)