Preparation of primary aralkyl urethanes and ureas and isocyanates derived therefrom
AssigneeAmerican Cyanamid Company
InventorsBalwant Singh, Laurence W. Chang, William A. Henderson, Jr.
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Abstract
A process is disclosed for the preparation of aralkyl mono- and diurethanes or ureas by carbamylmethylation, or acid-catalyzed addition at a temperature of 40.degree. C. to about 100.degree. C. of formaldehyde and esters of carbamic acid to aromatic hydrocarbons. Aralkyl carbamates and ureas formed by this process can be cracked directly to produce aralkyl diisocyanates, or hydrogenated and then cracked to produce aliphatic diisocyanates, or reacted directly with polyols to produce polyurethanes by functioning as blocked isocyanates.
Claims23
A process for production of a urethane or urea selected from the formulae:
- ##STR14## or a mixture of (I) and (II) wherein X is selected from --OR, --NR.sup.2.sub.2, ##STR15## R is alkyl or hydroxy alkyl of from about 1 to about 6 carbon atoms, aryl of from about 6 to about 10 carbon atoms or aralkyl of from about 7 to about 10 carbon atoms, R.sup.1 is hydrogen or alkyl of from about 1 to about 30 carbon atoms, R.sup.2 is alkyl of from about 1 to 6 carbon atoms, R.sup.3 is as defined for R.sup.1, R.sup.4 is as defined for R.sup.2, and when taken together, R.sup.3 and R.sup.4, are --CH.sub.2 (CH.sub.2).sub.3 CH.sub.2 -- or --CH.sub.2 (CH.sub.2).sub.2 CH.sub.2 --, n is an integer of 1 to 2 and m is 6-n, q is an integer of 1 or 2 and p is 8-q, and t is an integer of from 2 to 6, said process comprising reacting
- (a) an aromatic hydrocarbon of the formula ##STR16## wherein R.sup.1, m, n, p and q are as above defined, with (b) a carbamate of the formula
- H.sub.2 N--COX
- wherein X is as above defined;
- trioxymethylene, paraform, formcels and condensation products of (b) and the forementioned;
- and
- (d) an effective catalytic amount of an acid catalyst at a temperature of from about 30.degree. C. to about 150.degree. C. until formation of said urethane or urea compound (I), (II), or a mixture thereof is substantially complete.
A process as defined in claim 17 in which the pre-reaction mixture comprises a methylolalkyl carbamate, a methylene-bis-alkyl carbamate, or a cyclodehydrated hydroxy-methyl alkyl carbamate.
A process as defined in claim 27 wherein the hydrogenation catalyst comprises rhodium, ruthenium, nickel, compounds thereof or a mixture of any of the foregoing.
Dependencies are inferred from the claim text.