Glycerol from allyl chloride

Other routes for obtaining glycerol are also based on propylene. It can be produced from allyl chloride or from acrolein and isopropanol (see following sections). 

Allyl chloride is used to make intermediates for downstream derivatives such as resins and polymers. Approximately 90% of allyl chloride production is used to synthesize epichlorohydrin, which is used as a basic building block for epoxy resins and in glycerol synthesis. Allyl chloride is also a starting material for allyl ethers of phenols, bisphenol A and phenolic resins, and for some allyl esters. Other compounds made from allyl chloride are quaternary amines used in chelating agents and quaternary ammonium salts, which are used in water clarification and sewage sludge flocculation (Kneupper Saathoff, 1993). 

Allyl alcohol, CH2=CH-CH20H, is obtained from allyl chloride by alkaline hydrolysis. Oxydation of allyl alcohol gives acrolein, glycerol, formic acid, diallyl phthalate, acrylic acid. Allyl halogenids, allyl esters, allyl amines, allyl Grignard reagent can be obtained. End products are plastics, resins, plasticizers, varnish ingredients, pharmaceuticals, perfumes, flavors. 

From Allyl Ghloride. The hypochlorination of allyl chloride [107-05-1] gives a mixture of the glycerol dichlorohydrins, 2,3-dichloropropanol and 1,3-dichloropropanol about 7 3 ratio. Because of the poor solubiHty of allyl chloride in water, it is essential to minimize the formation of an organic phase in which direct chlorination of the allyl chloride results in the unwanted by-product 1,2,3-trichloropropane. 

Hydrolysis of Chlorinated Hydrocarbons. The production of oxygenated aliphatics by the hydrolysis of chlorinated hydrocarbons includes the synthetic glycerol process and the amyl alcohols process. Glycerol (7) is made from propylene via allyl chloride (CH2 CHCH2C1), and competes with glycerol made from fats and oils for use in dynamite and alkyd resins, as a tobacco humectant and cellophane plasticizer, in cosmetics and pharmaceuticals, and for other applications. Amyl alcohols have been made since 1926 by the alkali hydrolysis of a mixture of amyl chlorides, made by the chlorination of pentanes from natural gasoline. Production from this source far exceeds the supply from the fusel oil by-product of fermentation processes. Amyl alcohol and its derivatives are used mainly as solvents. 

Commerciol Dichlorohydrin consists of the above two isomers, the proportions of which depend on method of prepn d 1.36-1.39, bp 175-80°, flash p 74°, Glycerol was the main source for the prepn of glycerol chloro-hydrins until the process for direct substitutive chlorination of propylene to allyl chloride paved the way for synthesis by chlorohydrination of allyl chloride. In the synthesis from glycerol, excess HCI is used in the presence of 4% acetic acid. The reaction is run at 130° to yield 90% of product which is mainly the a,y-form. Synthesis from propylene yields a mixt of approx 70% a,/8-form 8c 30% a,y-form. Addn of HCI to epichlorohydrin, CH2 CHCH> Cl, at... 

A variety of processes for synthesizing glycerol from propylene are shown in Figure 1. The first glycerol process, put on stream in 1948, followed the discovery that propylene could be chlorinated in high yields to allyl chloride [107-05-1] (see Cm.OROCARBONS AND chlorohydrocarbons, allylchloride). 

Since allyl chloride could be converted to glycerol by several routes, the synthesis of glycerol from propylene [115-07-1] became possible. Propylene can also be oxidized in high yields to acrolein [107-02-8]. Several routes for conversion of acrolein to glycerol are shown in Figure 1. 

In the past, glycerol was produced mainly from propene via allyl chloride and epi-chlorohydrin, a process developed by I. G. Farben and in operation since 1943. Today, glycerol is obtained almost completely as a coproduct in oleochemistry (fat splitting) and biodiesel production (transesterification) with 110 kg crude glycerol or 100 kg pure glycerol per ton of biodiesel [37]. With the rise in biodiesel production, the availability increased while the price decreased drastically by approximately 66% within 15 years in the United States [38]. 

Epichlorohydrin (ECH) is made from propylene, the majority is via allyl chloride intermediate. Total consumption in 1999 was about 600 million lb. Uses for ECH include epoxy resins (65%), synthetic glycerin (22%), and others (paper treatment, specialty ionic exchange resin, glycerol, and glycidol derivatives). 

Derivation (1) By-product of soap manufacture (2) from propylene and chlorine to form allyl chloride, which is converted to the dichlorohydrin with hypo-chlorous acid this is then saponified to glycerol with caustic solution (3) isomerization of propylene oxide to allyl alcohol, which is reacted with peracetic acid, (the resulting glycidol is hydrolyzed to glycerol) (4) hydrogenation of carbohydrates with nickel catalyst (5) from acrolein and hydrogen peroxide. 

Epichlorohydrin, or 3-chloro-1,2-epoxy propane (bp 115°C), is more commonly prepared from propylene by chlorination to allyl chloride, followed by treatment with hypochlorous acid. This yields glycerol dichlorohydrin, which is dehy-drochlorinated by sodium hydroxide or calcium hydroxide (9). 

Uses From 3-chloropropene mainly epichlorohydrin (90 % of the use), glycerol, and allyl alcohol are prepared. The world production in 1997 was 800 0001 allyl chloride. 

Glycerol. Glycerol is the polyhydric alcohol most widely used for the preparation of alkyd resins and is obtained both synthetically and as a byproduct in the manufacture of soap. Most synthetic glycerol is obtained from propylene via allyl chloride ... 

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