GB788397A - Improvements in the preparation of resinous condensation products of alkenylphenols and aldehydes - Google Patents

Abstract

Alkenyl phenols are obtained by reaction of conjugated dienes with phenolic compounds. In an example, toluene, phenol and sulphuric acid are charged into a glass-lined reactor and butadiene added over a period of 15 minutes, the temperature being maintained at 55 DEG F. After agitation for 18 hours the acid layer which separates out is drawn off and the remaining reaction mixture is neutralized with sodium carbonate and then distilled to give a 59 per cent yield of monobutenylphenols and a mixture containing dibutenylphenols, higher boiling phenols and unreacted phenol and ethers.ALSO:A resinous condensation product, for use as coating compositions, lacquers and varnishes, and in making laminates and moulding powders, may be made by reacting a mixture of mono-and poly-alkenyl phenols containing at least 4 carbon atoms in each alkenyl radical with an aldehyde, preferably in the presence of an acidic or basic condensation catalyst. Phenol mixtures specified are butenyl-phenols, -cresols, -catechols, -2 : 3-dimethoxyphenols, -resorcinols, and -guaicols, 2-chlorobutenyl-cresol, and -phenol, 2-iodobutenylphenol, o- and p-cyclopentenyl-phenol, pentenyl-phenol, -cresol and -guaicol, halopentenyl-phenols and -guaicols. The preferred aldehyde is formaldehyde, e.g as formalin, paraldehyde or trioxymethylene. Catalysts specified are sodium, potassium and barium hydroxides, sodium and potassium carbonates, ammonia, and sulphuric, hydrochloric, phosphoric, acetic, propionic and oxalic acids. The catalysts are used in amount, e.g. of from 0.5 to 5 per cent by weight of the reactants, and the reactants are used in amounts, e.g. of from 0.5 to 5 mols. of aldehyde per mol. of phenol, and preferably from 1.5 to 2 : 1 when an alkaline catalyst is used and from 0.8 to 1 : 1 when an acid catalyst is used. The reaction is best effected by mixing the phenols and catalyst under an inert atmosphere such as nitrogen and or in the presence of sodium hydrosulphite, while maintaining the temperature at room temperature (25 DEG C.) until a solution is obtained; the aldehyde is then added with stirring while the temperature is kept below 35 DEG C., with subsequent acidification to a pH of 5 and separation into two layers. The resin layer, after removal of the water layer, is washed with water, mixed with a chelate or sequestrate, e.g. ethylenediaminetetracarboxylic acid (to form a complex with any iron present), and dehydrated. Many chelates or sequestrates are specified. The stability and compatibility with other synthetic resins of the products is enhanced by heating them with alcohols in an acidic or neutral medium, alcohols specified being methyl, ethyl, propyl, butyl, amyl, and 2-ethyl-hexyl alcohols, castor oil, butane diol-1 : 4, soya alcohols, allyl alcohol, ethylene glycol and alkyd resins containing OH groups. The alcohol and/or chelate &c. may however be added during the condensation reaction. In examples, a mixture of butenylphenols is reacted with (2) furfural, crotonaldehyde or acetaldehyde in the presence of caustic soda; (4) formaldehyde in the presence of caustic soda, and the product was further reacted with a sequestrate and with butanol; (5) formaldehyde in the presence of hydrochloric acid; a mixture of cyclopentenyl phenols was condensed with formaldehyde (3) in the presence of caustic soda; and (7) in the presence of hydrochloric acid; (6) a mixture of pentenyl-phenols was acid-condensed with formaldehyde; (8 to 14) butenylphenol-formaldehyde resins were heated with a number of different alcohols; (15) the resin of Example (4) was blended with an oleroresin varnish, with or without zinc oxide and titania; (16) the stability of the alcohol-reacted resins is compared with the unreacted resins.