Patent GB-822980-A (GB)
Title: Improvements in and relating to epoxides
IPC: C07D303/40
Filed: 1957-05-20
Abstract: Hard, tough, transparent polymers are prepared by the addition of sulphuric acid, preferably in an amount of 0.4% by weight, to organic triol tris (3,4-epoxycyclohexanecarboxylates) of the formula <FORM:0822980/IV (a)/1> wherein R represents a trivalent organic group having up to 22 carbon atoms and R1, R2, R3, R,4 R5 and R6 represent hydrogen atoms or alkyl groups having 1 to 4 carbon atoms (for preparation see Group IV (b)).  In an example, a mixture of 1,1,1-trimethylolpropane tris-(3,4-epoxycyclohexanecarboxylate) and 0.4% of sulphuric acid is allowed to stand overnight for 16 hours and is then heated to 120 DEG  C. for 35 minutes to form a gel which is then maintained at 160 DEG  for 1.5 hours whereby an opaque product is formed.ALSO:The invention comprises tris-(3,4-epoxycyclohexane carboxylates) having the formula <FORM:0822980/IV (a)/1> wherein R represents a trivalent organic group having up to 22 carbon atoms and R1, R2, R3, R4, R5 and R6 represent a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms.  The novel compounds may be prepared by reacting the corresponding organic triol tris-(3 - cyclohexenecarboxylate) with an epoxidizing agent, such as peracetic acid or acetaldehyde monoperacetate free from hydrogen peroxide, salts and sulphuric acid.  The epoxidizing agent is preferably employed as a solution in an inert organic solvent such as acetone, acetal, methyl ethyl ketone or butyl acetate. The reaction may be effected at - 25 DEG  to 150 DEG  C., preferably in the range of 10 DEG  to 90 DEG  C.  After completion of reaction the product may be isolated by feeding the reaction mixture into a still kettle containing ethyl benzene refluxing under reduced pressure, removing low-boiling components as distillate, recovering the epoxidized product as residue and further refining it, as by distillation. Organic triol tris-(3-cyclohexenecarboxylates) used as starting materials in the above process may be prepared by mixing a 3-cyclohexenecarboxylic acid with an organic triol in a mol. ratio of about 3 mols. of acid per mol. of triol and heating the mixture to 100 DEG  to 200 DEG  C. and removing water continuously as an azeotrope with a solvent such as benzene or toluene.  The organic triols which may be used include aliphatic triols, such as 1,2,3 - propanetriol, trimethylolmethane, 1,1,1 - trimethylolethane, 1,1,1 - trimethylolpropane or 1,2,6 - hexanetriol; cycloaliphatic or aromatic triols such as 1-allyloxy-2,4,6-trimethylolbenzene, 1 - phenylpropane - 1,2,3-triol or 1,4 - benzopyran - 3,5,7 - triol. The 3-cyclohexenecarboxylic acids are obtained by oxidation of the corresponding aldehydes prepared by Diels-Alder condensation of butadiene or its homologues with a ,b -unsaturated aldehydes. Examples of combinations of reactants are given.  Detailed examples of the preparation of 1,1,1 - trimethylolpropane tris - (3,4 - epoxycyclohexanecarboxylate) and 1,2,3 - propanetriol tris - (3,4 - epoxycyclohexanecarboxylate) are given. 1,2,6-Hexanetriol tris(1-ethyl-3,4-epoxycyclohexanecarboxylate, 1,2,6 - hexanetriol tris - (6 - methyl - 3,4 - epoxycyclohexanecarboxylate) and the triesters of 1,1,1-trimethylolpropane or 1,2,3-propanetriol with 1-methyl3,4-epoxycyclohexanecarboxylic acid and 6-methyl - 3,4 - epoxycyclohexenecarboxylic acid are obtained by similar methods. The products are useful for the formation of polymers (see Group IV(a)).