Patent GB-694060-A (GB)
Title: Process for the manufacture of ethers of glycerols
IPC: C07C43/13
Filed: 1950-12-22
Abstract: A process for the production of a b -monoether of a glycerol comprises heating a corresponding b -monoether of a glycerol halohydrin with water under sufficient pressure substantially to maintain the reaction mixture liquid, while maintaining a hydrogen ion concentration in the liquid medium corresponding to a pH value between 7 and 1.5, in order to effect hydrolysis.  The reaction is preferably carried out in the presence of buffer salts of non-gaseous acids having pKa values within the range of about 6.5 to 3.5.  Thus the process may be carried out by heating the starting material with excess water containing sodium acetate or another salt of a strong base and a weak normally liquid-to-solid acid.  The desired product may be recovered by fractionation, steam distillation, solvent extraction, crystallization or by combination of such processes.  The hydrolysis may be carried out in pure water or a dilute solution of a weak acid, e.g. acetic acid.  Buffer salts mentioned include potassium acetate, mono- and disodium phosphates and mixtures thereof, sodium citrate, sodium benzoate, disodium pyrophosphate and sodium-tartrate and sufficient is added to maintain the desired pH. Unreacted halohydrin may be recycled and the process may be carried out batchwise or continuously.  The weak acid set free during the reaction may be separated from the halide salt and after neutralization may be recycled, combined, if desired, with recycling of the unreacted starting material.  The etherifying radical in the starting material may be derived from a saturated aliphatic, cycloaliphatic or aromatic alcohol, especially from a b -g -olefinic alcohol or a phenol.  The process is applicable to ethers of halohydrins in which the halogen atom or atoms is or are bromine, chlorine and/or iodine.  Ether starting materials mentioned include the allyl ether of glycerol a ,g -dichlorohydrin, the allyl ether of glycerol a ,g -dibromohydrin, the allyl ether of b -ethyl glycerol a ,g -dichlorohydrin, the allyl ether of b -methyl glycerol a ,g -dichlorohydrin, the allyl ether of b -hexylglycerol a ,g -dichlorohydrin, the methallyl ether of b -methyl-glycerol a ,g -dichlorohydrin, the 2-ethyl-2-propenyl ether of glycerol a ,g -dichlorohydrin, the 2-butyl-2-propenyl ether of b -octylglycerol a ,g -dichlorohydrin, the 2-octyl 2-propenyl ether of glycerol a ,g -dichlorohydrin and the cinnamyl ether of glycerol a ,g -dibromohydrin, the corresponding ethers of b ,g -olefinic alcohols with glycerol a -monohalohydrins, ethers of glycerol mono- and dihalohydrins corresponding to the b -ethyl monoether of glycerol, the b -propyl monoether of glycerol, the b -isopropyl monoether of glycerol, the b -2-hydroxyethyl monoether of glycerol, the b -2-methoxyethyl mono-ether of glycerol, the b -dodecyl monoether of glycerol, the b -cyclohexyl-monoether of glycerol, the b -octadecyl monoether of glycerol and b -2-methoxy, 2-ethoxy-ethyl mono-ethers of glycerol.  Aryl type b -monoethers of glycerol which can be prepared include the phenyl-, o-cresyl-, m-cresyl-, p-cresyl-, o-nitrophenyl-, 2,4-dinitrophenyl-, o-cyclohexylphenyl- and naphthyl b -monoethers of glycerol.  In examples: (I-III) the b -allyl monoether of glycerol is prepared by heating in an autoclave the corresponding a ,g -dichlorohydrin with sodium acetate in water; (IV) the b -allyl monoether of glycerol is similarly obtained by heating the b -allyl monoether of glycerol a -monochlorohydrin with potassium acetate; (V) the b -isopropyl monoether of glycerol is obtained by heating in an autoclave the isopropyl ethers of glycerol a ,g -dichlorohydrin with water and sodium acetate.  Other ethers, e.g. the methyl, ethyl, propyl, sec.-butyl, pentyl, decyl or tetradecyl ethers of a ,g -dichlorohydrins may be used as starting materials; (VI) the b -(o-cresyl) monoether of glycerol is obtained by heating in an autoclave the o-cresyl ether of glycerol a ,g -dichlorohydrin with water and sodium acetate.  Other aryl type b -ethers of glyceryl halohydrins may be used, e.g. the phenyl-, m-cresyl-, benzyl-, naphthyl-, guaicyl-, carvacryl or thymyl ethers of glycerol a ,g -dichlorohydrin and glycerol a -monohydrin; (VII) the b -methallyl monoether of glycerol is heated in an autoclave with water containing disodium hydrogen phosphate and phosphoric acid. Other allyl type b -ethers of glycerol halohydrins which may be employed include the crotyl ether of glycerol a ,g -dichlorohydrin, b -methallyl ether of glycerol a -monochlorohydrin, b -ethylallyl ether of b -methyl glycerol-a ,g -dichlorohydrin, b -cinnamyl monoether of glycerol a -bromohydrin, 3-chloroallyl ether of glycerol a ,g -dichlorohydrin and (2-ethyl-3-propyl allyl) ether of glycerol a ,g -dichlorohydrin. b -Monoether-glycerol halohydrins are stated to be prepared by reaction between a glycerol dihalohydrin and a hydrocarbon halide, e.g. between o-chlorotoluene and glycerol a ,g -dichlorohydrin and between isopropylchloride and glycerol a ,g -dichlorohydrin.  Allyl type ether starting materials may be produced by reacting a hydrocarbon of the allyl type with a glycerol epichlorohydrin in the presence of a cuprous catalyst.