Patent GB-948494-A (GB)
Title: Improvements in or relating to phenolic di-ketones
Inventor: THORNTON DAVID ARTHUR
IPC: C07C49/825
Filed: 1960-08-08
Abstract: The invention comprises phenolic diketones of the general formula: <FORM:0948494/C2/1> where the various R groups are the same or different and are each a hydrogen atom or a hydrocarbon substituent and in which the hydroxyl group is in the meta or para position with respect to the b -diketone substituent and processes for the preparation thereof which comprise (a) reacting an ester of a hydroxy compound of the general formula: <FORM:0948494/C2/2> in which the hydroxyl group is in the meta or para position with respect to the -COCH2R5 substituted with an acid anhydride of the general formula (R6CH2CO)2O in the presence of a Lewis acid catalyst and decomposing the complex so formed and removing the ester grouping by hydrolysis or alcoholysis; (b) reacting a m- or p-hydroxybenzoylchloride of the general formula: <FORM:0948494/C2/3> with a sodio derivative of an acetoacetic ester, saponifying the product and decarboxylating the saponified product by heating in the presence of an aqueous solution of an inorganic acid or of a dilute aqueous solution of a caustic alkali; (c) condensing a phenolic ketone of the general formula: <FORM:0948494/C2/4> in which the hydroxyl group is in the meta or para position with respect to the -COCH2R5 substituent with an ester of the general formula R6CH2COOR1 where R1 represents an alkyl or aralkyl grouping in the presence of an alkali metal or alkali metal alkoxide or aralkoxide or (d) reacting a compound of the first general formula above where R5 is a hydrogen atom with potassium tertiary butoxide and reacting the product with a halide R5X where R5 is a hydrocarbon group and X is a halogen atom and acidifying the product.  Specific products described include p-hydroxybenzoylacetone, 3-methyl-4-hydroxybenzoylacetone, 1-p-hydroxyphenyl-1, 3-pentanedione and 1-p-hydroxyphenyl-2-methyl-1, 3-butandione.  Examples are furnished.  The products are employed as additives in adhesives comprising phenol-formaldehyde resins and/or epoxide resins (see Division C3). Specification 948,495 is referred to.ALSO:Adhesives comprising phenol-formaldehyde resin and/or an epoxide resin contain as additive a phenolic diketone of the general formula: <FORM:0948494/C3/1> where the various R groups are the same or different and are each a hydrogen atom or a hydrocarbon substituent and in which the hydroxyl group is in the meta or para position with respect to the b -diketone substituent (see Division C2). Additionally superpolyamides and polyvinyl formols may be present. In Example IX woven glass cloth is dipped in an adhesive containing a phenol formaldehyde resin, aluminium powder, a polyvinyl formal, an epoxy resin having an epoxide content of 2.3 epoxy equivalents per kilogram, acetone and p-hydroxybenzoylacetone, dried at room temperature and is employed to bond aluminium panels by heating under pressure. The epoxy resin is obtained by reacting 2,2-bis-(p-hydroxyphenyl) propane and epichlorohydrin under akaline conditions.  The phenol-formaldehyde resin is obtained by boiling a mixture of phenol, neutralised formalin, water and sodium hydroxide under reflux, removing water under reduced pressure, adding further sodium hydroxide and ethanol, heating to 50 DEG C. and finally adding hexamine until a clear solution is obtained. Specification 948,495 is referred to.