Patent GB-679536-A (GB)
Title: Improvements in epoxide preparation
Filed: 1948-05-21
Abstract: "Complex halohydrins" are made by condensing an epihalohydrin with a polyhydric compound such as a polyhydric phenol or alcohol or mixture thereof.  They are treated with alkali metal zincates, silicates or aluminates in non-aqueous media to yield epoxides.  Epihalohydrins exclude epifluorohydrins. Many polyhydric compounds are specified representative being ethylene glycol, 1,12-dihydroxy octadecane, 1,4-dihydroxycyclohexane, glycerol, mannitol, polyallyl alcohol, 4,41-dimethylol diphenyl triglycerol, dimethylolanisoles, the bis-(beta-hydroxyethyl ether) of bisphenol, condensates of alkylene oxides with polyhydric alcohols, fructose, resorcinol, monostearin and glycerol monochlorohydrins.  Homologues of epihalohydrins, e.g. 1,4-dichloro-2,3-epoxybutane may also be used.  Epichlorhydrin is preferred.  Many condensation agents are specified representative being Friedel-Crafts catalysts, e.g. AlCl3 and BF3 etherates, acid type catalysts, e.g. HF and H2SO4 and others, e.g. POCl3 and SbCl5. Generally, the condensation catalyst is used in up to about 5 per cent, usually less than 1 per cent, of the total reactants and temperatures indicated are 25-175 DEG  C., advantageously 75-125 DEG C.  With high melting and relatively insoluble polyhydric alcohols it is an advantage to use a solvent which may be a polyhydric alcohol which enters into the reaction. Thus pentaerythritol and poly-pentaerythritol may be reacted in ethylene glycol, diglycerol or trimethylol propane.  Solvents for the dehydrohalogenation include hydrocarbons, ketones, ethers and halides and members of these classes are specified, dioxane being preferred.  Solvents completely miscible with water facilitate filtration particularly when sodium zincate is used.  The epoxide obtained may contain hydroxy and halogen groups.  In dehydro-halogenation when sodium aluminate is used, temperatures of -25-125 DEG  C. are specified, preferably 70-105 DEG  C. for a reaction time of 1-3 hours, the aluminate is preferably in slight excess and 1-15 per cent or 30 per cent of water is preferably added, with zincates, temperatures of -125-125 DEG  C. are specified although in general lower temperatures than those for aluminates are used, the quantity of salt used is from 1/3 rd to 1 mol. equivalent, depending on whether excess epihalohydrin or polyhydric compound is used, the product containing halogen when less than an equivalent of zincate is used and with silicates temperatures of -25-125 DEG  C., preferably 50-105 DEG  C., are used and quantities taken similar to those of the zincates.  Silicates are more effective when ground.  Products are recovered by filtration and distillation.  Super- and sub-atmospheric pressure may be used.  In examples, a condensation product prepared by reacting 18 mols. of epichlorhydrin with 6 mols. of glycerol in ethereal BF3 is treated with sodium aluminate in (1) dioxane, (2) ethyl ether and in (3) with caustic soda in ether (this example is given for comparative purposes only) with dioxane and (4) sodium ortho-silicate, (5) sodium metasilicate pentahydrate, (6) sodium sesquisilicate and (7) sodium zincate, condensation products from glycerol and epichlorhydrin in ratios of 1 : 2 and 1 : 4 respectively are reacted with (8) sodium zincate in dioxane and (9) sodium aluminate in dioxane, (10) 1 mol. of trimethylol propane is condensed with 3 mols. of epichlorhydrin and reacted in dioxane with sodium aluminate, (11) equimolar quantities of glycerol monochlorhydrin and epichlorhydrin are condensed and reacted with sodium aluminate in dioxane, (12) epichlorhydrin (2 mols.) and 1,12-dihydroxy-octadecane (1 mol.) are condensed and reacted with sodium aluminate in dioxane, (13) epichlorhydrin (3.3 mols.) and erythritol (0.84 mols.) are condensed and reacted with sodium zincate in dioxane containing a little water, (14) epichlorhydrin (5 mols.) and triglycerol (1 mol.) are condensed and reacted as in (13), (15) epichlorhydrin (6 mols.) and polyallyl alcohol (400 gms.) are condensed and treated with sodium zincate in dioxane, (16) epichlorhydrin (5.3 mols.), dextrose (0.7 mol.) and ethylene glycol (0.7 mol.) are condensed and reacted with aqueous dioxane and sodium zincate, (17) epichlorhydrin (7 mols.) and sorbitol (1 mol.) are condensed and reacted with sodium zincate in dioxane, (18) epichlorhydrin (3 mols.) and sorbitol (1 mol.) are condensed and reacted with sodium aluminate in aqueous dioxane, (19) epichlorhydrin (6 mols.) and sorbitol (1 mol.) are condensed and reacted as in (18), (20) epichlorhydrin (12 mols.) commercial pentaerythritol (317 gms.) and trimethylol propane (0.8 mol.) are condensed and reacted as in (18), (21) ethylene glycol (2 mols.), nitration grade pentaerythritol (7 mols.) and epichlorhydrin are condensed and reacted as in (18), (22) epichlorhydrin (15 mols.), dipentaerythritol (1.5 mols.) and trimethylol propane (3 mols.) are condensed and reacted as in (18), (24) ethylene oxide (157 gms.), diglycerol (1.0 mol.), pentaerythritol (1.25 mols.) and epichlorhydrin (9 mols.) are condensed and reacted as in (18), (25) a soybean monoglyceride (711 gms.) and epichlorhydrin (4 mols.) are condensed and reacted with sodium zincate in dioxane, (26) glycerol phthalate (314 gms.) and epichlorhydrin (7 mols.) are condensed and reacted as in (25) and in (27) bisphenol (228 gms.) and epichlorhydrin (185 gms.) are condensed and reacted with sodium aluminate in dioxane.  The products of the examples all contained chlorine.  The Specification as open to inspection under Sect. 91 relates to aluminates, zincates and silicates generally and includes in the preparation of complex halohydrins many specified sulphur containing compounds, e.g. 2,21-dihydroxy diethyl sulphide, 2-mercapto ethanol and dihydroxy diaryl sulphones.  Complex halohydrins are also made by reacting hydroxyepoxides, e.g. glycidol, with halogen-containing compounds, e.g. organic acid halides such as benzoyl and acetyl chloride, inorganic acid halides such as ACl3 and SOCl2 and compounds such as diethyl and ethyl dichlorosilane.  The halogen atoms of the products may be replaced by such groups as OH, SCN, S or NH2 by reaction with such compounds as sodium bicarbonate, thiocyanate or sulphide or ammonia.  They may also be reacted with alkali metal phenolates to give resins.  This subject-matter does not appear in the Specification as accepted.  In two additional examples, (27) bisphenol and epichlorhydrin are condensed in the presence of sodium acetate and the products reacted with sodium aluminate in dioxane, and (29) the epichlorhydrin-glycerol product of (1) is reacted with aqueous caustic soda and bisphenol to give a resinous product.ALSO:Epoxides are made by reacting a basic reacting alkali metal aluminate, silicate or zirconate with a halohydrin in a substantially non-aqueous medium.  Typical of many specified alkali metal reactants are Na3AlO3, K2Al2O4, Na2SiO3.5H2O and Na4SiO4 the sodium and potassium salts being preferred.  The halohydrins may be aliphatic, cycloaliphatic and aryl-substituted aliphatic compounds containing at least one halogen atom and at least one hydroxy group each of which is attached to a different, preferably adjacent, carbon atom of the molecule.  Many halohydrins are specified representative being ethylene chlorhydrin, propylene bromhydrin, 1-chloro-3-hydroxy butane, 1,4-dihydroxy-2,3-dichloro - butane, 1 - chloro - 2 - hydroxy cyclohexane and 1 - bromo - and 1 - iodo - 2-hydroxy-2 phenyl ethane. So-called "complex halohydrins" may also be used.  They are made by condensing an epihalohydrin which does not include fluorohydrins with a polyhydric compound such as a polyhydric phenol or alcohol or mixtures thereof in the presence of condensing agents.  Many polyhydric compounds are specified representative being ethylene glycol, 1,12-dihydroxy octadecane, 1,4-dihydroxycyclohexane, glycerol, mannitol, polyallyl alcohol, 4,41-dimethylol diphenyl, triglycerol, dimethylolamides, the bis - (beta hydroxyethyl ether) of bisphenol, condensates of alkylene oxides with polyhydric alcohols, fructose, resorcinol, monostearin and glycerol monochlorhydrins. Homologues of epihalohydrins, e.g. 1,4-dichloro-2,3-epoxy-butane may also be used.  Epichlorhydrin is preferred.  Many condensing agents are specified representative being Friedel-Crafts catalysts, e.g. AlCl3 and BF3 etherates, acid-type catalysts, e.g. HF and H2SO4 and others, e.g. SbCl5.  Generally the condensation catalyst is used in up to about 5 per cent, usually less than 1 per cent, of the total reactants and temperatures indicated for this reaction are 25-175 DEG C. advantageously 75-125 DEG  C.  With high melting and relatively insoluble polyhydric alcohols it is advantage to use a solvent which may be a polyhydric alcohol which itself enters into the reaction. Thus pentaerythritol and poly-pentaerythritol may be reacted in ethylene glycol, diglycerol or trimethylol propane.  Solvents for the dehydrohalogenation reaction include hydrocarbons, ketones, ethers and halides and members of these classes are specified, dioxane being preferred.  Solvents completely miscible with water facilitate filtration particularly when sodium zincate is used. When complex halohydrins are reacted the epoxide obtained may contain hydroxy and halogen groups.  In dehydrohalogenation when sodium aluminate is used temperatures of -25 DEG  to 125 DEG  C. are specified, preferably 70-105 DEG  C. for a reaction time of 1-3 hours, the aluminate is preferably in slight excess and 1-15 per cent or 30 per cent of water is preferably added, with zincates temperatures of -25-125 DEG  C. are specified although in general lower temperatures than those employed for aluminates are used, the quantity of salt used is preferably substantially equivalent to the theoretical although with complex halohydrins quantities of from 1/3 to 1 mol. equivalent are indicated depen