Patent GB-338937-A (GB)
Title: Improved process for the manufacture and production of artificial resins
IPC: C08G12/42
Filed: 1929-07-29
Abstract: 338,937. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). July 29, 1929. Urea-aldehyde condensation products.-Urea or thiourea and formaldehyde condensation products of a non-inflammable; character are obtained by effecting the condensation in the presence of organic solvents consisting of or containing a substantial proportion of halogen-aryl substituted aliphatic alcohols and preferably in the presence of an acid reacting substance, the reaction being accelerated by heating. It is stated that the substituted alcohols appear to take part in the reaction so that products are obtained which contain the halogen chemically combined to resemble the ethers or acetals obtainable according to Specification 266,752. Examples of halogenaryl substituted aliphatic alcohols are the mono- and di-bromo-benzyl alcohols and the, chlorobenzyl alcohols, and these substituted alcohols are defined so as to include the use of alcohols in which the aliphatic chain is connected with the aromatic nucleus by at least one oxygen atom, such as the glycol mono-halogen-aryl ethers and glycol mono-brombenbzoic esters, or mixtures of such compounds with each other or with organic solvents such as alcohols, esters, or ethers, the halogen substituted alcohols ,in each case being present in the mixtures in a proponderating quantity. The formaldehyde used is preferably in the form of paraformaldehyde or trioxymethlene, and the urea may be in the form of N-methyl urea, a methylol or anhydride thereof, thiourea. and its similar derivatives, and these ureas may be used separately or together as a mixture. The reaction is generally accelerated by the addition of acid reacting substances such as acetic acid, hydrochloric acid, and potassium tetraoxalate, or preferably by an addition of buffer mixtures which with water furnish a constant hydrogen-ion concentration, such as primary alkali metal phosphates. The condensation products may be freed from the solvents in which they have been prepared by distillation or by precipitation; in the latter case by the addition of organic liquids, as described in Specification 327,673. The condensation may be carried out in the presence of natural or artificial resins, or of cellulose esters such as cellulose nitrate., soluble in the solvents used, so that mixed products can be obtained; the addition of these substances may also be made after the condensation. The condensation products may be moulded or dissolved in suitable solvents such as glycol monoalkyl ethers or glycol mono-esters of organic acids, and, together with cellulose esters, resins, plasticizing agents, and other organic substances, worked up into lacquers, films, and artificial masses which are combustible with difficulty or are incombustible. Specifications 260,253, 261,029, 262,148, 296,361, and 301,696 also are referred to. The following examples are, described, the reaction temperatures being generally between 80-120‹ C. : (1) Dimethylol urea is suspended in ortho-chloro-benzyl alcohol, oxalic acid added, and the mixture heated until the urea has dissolved; calcium carbonate is then stirred in and the solution cooled and filtered. The condensation product is freed from the solvent by distillation in the steam, and is dried and pulverized. On dissolving in ethylene glycol mono-methyl or mono-ethyl ether or dioxane., a lacquer is obtained which gives a non-inflammable coating. (2) Dimethyllol urea. is condensed in ethylene glycol-mono-bromo-phenyl ether and the product precipitated by the addition of ether. (3) Dimethyllol thiourea is condensed in o-chlorobenzyl alcohol in the presence of glacial acetic acid and the reaction mixture neutralized .by the addition of calcium carbonate subsequently added and filtered; the condensation product is precipitated from the filtrate by adding ether. (4) The anhydride of dimethylol urea in ethylene glycol mono-bromo-phenyl ether or dichloro- or dibromobenzyl alcohol is condensed in the presence of a small quantity of formic acid. Subsequently calcium carbonate is added with stirring and the condensation product is precipitated from the filtrate by the addition of benzene. (5) Trioxymethylene in ethylene glycol mono-bromo-phenyl ether, and urea are condensed in the presence of a small quantity of oxalic acid; after the addition of calcium carbonate the condensation product is precipitated from the filtrate by the addition of methyl acetate. (6) Dimethylurea and dimethylthiourea, together with a small quantity of oxalic acid, are stirred into fused dibromo-benzyl alcohol. After the, addition of tertiary sodium phosphate, calcium carbonate is added for neutralization.: the reaction product is precipitated from the filtrate by ether. (7) Fused. dichloro-benzyl alcohol and trioxymethylene are incorporated with the addition of a small quantity of alcoholic potash; thiourea and a small quantity of phosphoric acid solutions are then added and the reaction mass heated. The filtrate obtained after first neutralizing with calcium carbonate is worked up as in example 3. (8) Dimethyl urea is dissolved in fused ethylene glycol mono-bromosalicylic ester in the presence of m-xylene sulphonic acid. After neutralizing with tertiary sodium phosphate and calcium carbonate, filtering and precipitating with acetone, the dried condensation product is pressed into moulded articles. (9) Dibromo-benzyl alcohol and benzyl alcohol are heated in the presence of toluene sulphonic acid, dimethylol urea then added, and the reaction mass heated. After neutralizing with tertiary sodium phosphate and calcium carbonate and filtering, the condensation product is isolated by steam distillation. (10) Trioxymethylene and o-chloro-benzyl alcohol are fused in the presence of alcoholic potash, urea and thiourea added, together with a trace of sulphuric acid as condensing agent. The condensation product is separated by neutralizing, filtering, and steam distillation.