Patent GB-880423-A (GB)
Title: Improvements in or relating to a process for preparing glycidyl polyethers of polyhydric phenols
IPC: C07D301/28
Filed: 1958-10-02
Abstract: Glycidyl polyethers of polyhydric phenols are prepared by a continuous process comprising continuously introducing into the input end of a first reactor epichlorhydrin or glycerol dichlorohydrin and a polyhydric phenol in a mol. ration from 5:1 to 25:1, water and acetone in an amount such that the weight ratio of the hydrin to acetone is about 1:1 to 1:0,5 and continuously passing this mixture into a series of at least two other separate reactors, in all the reactors (1) maintaining the mixture under agitation to effect intimate contact of the reactants, (2) maintaining the temperature between 38 DEG  and 88 DEG C. and (3) adding a portion of the equivalent amount of alkali metal hydroxide as an aqueous solution, the total amount of water introduced into the system being such that the amount of water in the mixture removed from the output end of the final reactor is between 7 and about 18% by weight, continuously removing the mixture from the said output end to a phase separator, separating the organic phase and recovering the glycidyl polyether therefrom.  In a modification, the mixture is passed through an additional phase separator introduced before the last or penultimate reactor, the organic phase is continuously recovered from this separator and fed to the last or penultimate reactor and the aqueous layer recovered from the additional phase separator is used to wash the mixture recovered from the final reactor, the amount of water in the combination of final reaction mixture and wash liquor being p between 7 and about 18%.  The equivalent amount of alkali metal hydroxide is defined as being at least that amount equivalent to the phenolic hydroxy groups introduced into the first reactor or in the case of dichloro glycerine, to at least twice that amount. The water content of the final reaction mixture is made up by the water introduced initially and in the aqueous alkali and sometimes by water added at points along the system to facilitate solution of sodium phenate as of salt formed in the reaction.  The process may be operated under pressure.  The product may be neutralized, e.g. with sodium hydrogen phosphate before separation.  Two forms of apparatus are described having six reactors in series, in one case an additional separator is interposed between the 4th and 5th reactors. Examples describe the reaction of epichlorhydrin with 2:2-bis (4-hydroxy phenyl) propane yielding liquid polyethers which are cured to solid castings using a reaction product of meta-phenylene diamine and phenyl glycidyl ether as curing agent. Comparative experiments are described employing ethanol or methyl isobutyl ketone in place of the acetone or wherein a one stage reaction is effected.  Numerous other polyhydric phenols are specified: methyl resorcinol, resorcinol, hydroquinone, chlorohydroquinones, phloroglucinol, 1, 5-dihydroxynaphthalene, 4, 41 dihydroxydiphenyl, 3-hydroxyphenyl salicylate, 4-salicoyl amino phenol, a long list of bis-phenols, and complex polyhydric phenols obtained by condensing phenols with aldehydes (e.g. novolac resins), cardanol, aliphatic diols or unsaturated fatty oils.  Specification 785,415 is referred to.ALSO:Glycidyl polyethers of polyhydric phenols are prepared by a continuous process comprising continuously introducing into the input end of a first reactor epichlorhydrin or glycerol dichlorohydrin and a polyhydric phenol in a mol ratio from 5:1 to 25:1, water and acetone in an amount such that the weight ratio of the hydrin to acetone is about 1:1 to 1:0.5 and continuously passing this mixture into a series of at least two other separate reactors, in all the reactors (1) maintaining the mixture under agitation to effect intimate contact of the reactants, (2) maintaining the temperature between 38 DEG  and 88 DEG C. and (3) adding a portion of the equivalent amount of alkali metal hydroxide as an aqueous solution, the total amount of water introduced into the system being such that the amount of water in the mixture removed from the output end of the final reactor is between 7 and about 18% by weight, continuously removing the mixture from the said output end to a phase separator, separating the organic phase and recovering the glycidyl polyether therefrom.  In a modification, the mixture is passed through an additional phase separator introduced before the last or penultimate reactor, the organic phase is continuously recovered from this phase separator and fed to the last or penultimate reactor and the aqueous layer recovered from the additional phase separator is used to wash the mixture recovered from the output end of the final reactor, the amount of water in the combination of final reaction mixture and wash liquor being between 7 and about 18%.  Acetone and epichlorhydrin also recovered in the separation of the glycidyl polyether, may be recycled to the feed mixture.  The equivalent amount of metal hydroxide is defined as being at least that amount equivalent to the phenolic hydroxyl groups introduced into the first reactor or in the case of glycerol dichlorohydrin, to at least twice this amount; desirably an excess is used and equal portions are preferably added to the reactors.  The water content of the mixture from the final reactor is controlled mainly by that introduced as feed and in the aqueous alkali, but some water may be added at points along the system to facilitate solution of sodium phenate or of the sodium halide formed.  The final reaction mixture may be neutralized with, for example, sodium hydrogen phosphate before separation.  The process may be effected under pressure.  Two forms of apparatus are described having six reactors arranged in series, in one case there being interposed the additional phase separator between the 4th and 5th reactors. The products from a dihydric phenol are represented as <FORM:0880423/IV (b)/1> where R is the residue of the phenol and n is O when the ratio of hydrin to phenol is about 10-15:1 and is 1-2 when this ratio is about 5-9:1.  Examples describe the reaction of epichlorhydrin with 2,2-bis (4-hydroxyphenyl) propane using both forms of apparatus yielding liquid polyethers which are curable (see Group IV(a)).  Comparative experiments describe the same reaction using the modified apparatus but replacing the acetone by ethanol or methyl ethyl ketone, or using a single reactor.  Numerous other polyhydric phenols are mentioned including resorcinol, chlorohydroquinones, 2,2-bis (2,5-dibromo-4-hydroxyphenyl) butane, 3-hydroxyphenyl salicylate, 4- salicoyl amino phenol and complex polyhydric phenols of resinous type (see Group IV(a)). Specification 785,415 is referred to.