Ethylene glycol dehydration

Ethylene glycol dehydration, 27 hydration, 5 Evaporation, 11,13 through stagnant gas, 629-632 EVF, 103... 

Although most of the installed solvent dehydration systems have been for ethanol dehydration, dehydration of other solvents including 2-propanol, ethylene glycol, acetone, and methylene chloride, has been considered. 

A selection of industrial appHcations of extractive distillation includes (/) the separation of the / -butane—butadiene azeotrope in mixed C -hydrocarbon streams using furfural [98-01-17, as the solvent (36) (2) the dehydration of ethanol using ethylene glycol [107-21-1] (37—39) (J)... 

Membrane Pervaporation Since 1987, membrane pei vapora-tion has become widely accepted in the CPI as an effective means of separation and recovery of liquid-phase process streams. It is most commonly used to dehydrate hquid hydrocarbons to yield a high-purity ethanol, isopropanol, and ethylene glycol product. The method basically consists of a selec tively-permeable membrane layer separating a liquid feed stream and a gas phase permeate stream as shown in Fig. 25-19. The permeation rate and selectivity is governed bv the physicochemical composition of the membrane. Pei vaporation differs From reverse osmosis systems in that the permeate rate is not a function of osmotic pressure, since the permeate is maintained at saturation pressure (Ref. 24). 

If ethylene glycol is subjected to vigorous dehydrating conditions, simple molecules such as dioxan and acetaldehyde may be prepared (Figure 19.10). 

Cyclohexadiene has been prepared by dehydration of cyclohexen-3-ol,3 by pyrolysis at 540° of the diacetate of cyclohexane-1,2-diol,4 by dehydrobromination with quinoline of 3-hromocyclohexene,6 by treating the ethyl ether of cyclohexen-3-ol with potassium bisulfatc,6 7 by heating cyclohexene oxide with phthalic anhydride,8 by treating cyclohexane-1,2-diol with concentrated sulfuric acid,9 by treatment of 1,2-dibromocyclo-hexane with tributylamine,10 with sodium hydroxide in ethylene glycol,10 and with quinoline,6 and by treatment of 3,6-dibromo-cyclohexene with sodium.6... 

Uses Solvent for nitrocellulose, ethyl cellulose, polyvinyl butyral, rosin, shellac, manila resin, dyes fuel for utility plants home heating oil extender preparation of methyl esters, formaldehyde, methacrylates, methylamines, dimethyl terephthalate, polyformaldehydes methyl halides, ethylene glycol in gasoline and diesel oil antifreezes octane booster in gasoline source of hydrocarbon for fuel cells extractant for animal and vegetable oils denaturant for ethanol in formaldehyde solutions to inhibit polymerization softening agent for certain plastics dehydrator for natural gas intermediate in production of methyl terLbutyl ether. 

This cobalamin-dependent enzyme [EC 4.2.1.28] catalyzes the conversion of propane-1,2-diol to propanal and water. The enzyme also dehydrates ethylene glycol to acetaldehyde. 

In a similar manner, coccinelline (99) and precoccinelline (100) have been synthesized from 2,6-lutidine (351) (336,450). Thus, treatment of the monolithium derivative (153) of 351 with P-bromopropionaldehyde dimethylacetal gave an acetal, which was converted to the keto acetal (412) by treatment with phenyllithium and acetonitrile. Reaction of 412 with ethylene glycol and p-toluenesulfonic acid followed by reduction with sodium-isoamyl alcohol gave the cw-piperidine (413). Hydrolysis of 413 with 5% HCl gave the tricyclic acetal (414) which was transformed to a separable 1 1 mixture of the ketones (415 and 416) by treatment with pyrrolidine-acetic acid. Reaction of ketone 416 with methyllithium followed by dehydration with thionyl chloride afforded the rather unstable olefin (417) which on catalytic hydrogenation over platinum oxide in methanol gave precoccinelline (100). Oxidation of 100 with m-chloroperbenzoic acid yielded coccinelline (99) (Scheme 52) (336,450). 

The partial reduction of benzofuroxans, discussed in Section 4.05.5.2.4, represents an effective route to numerous benzofurazans. The conversion may be achieved either directly by deoxygention, for example, with sodium azide in ethylene glycol or acetic acid <75Ci(M)243> or using phosphites, or in two stages via the dioxime with subsequent dehydration as described above. 

Calculated from the dehydration amount of low temperature structural water between 300-650°C, Ethylene glycolated. 

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