Process for preparing aminonitriles

Claim 1

In a process for preparing an aminonitrile having the formula R-N (CH2CN)2 wherein R is a straight chain non-branched alkyl group having about one to 12 carbon atoms, the improvement comprising the following sequential steps: a. forming a first mixture by admixing; (i) a primary amine having the formula R-NH2, wherein R is as defined supra; (ii) formaldehyde; and (iii) water and cooling the resulting first mixture to maintain the temperature thereof within a range of about 0-35*C. by removing heat produced by an exotherm resulting from mixing the primary amine, the formaldehyde, and the waTer, the mole ratio of primary amine to formaldehyde being about 1:2-2.5 and the weight ratio of primary amine to water being about 1:0.4-2; b. forming a second mixture by admixing; (i) sulfuric acid; (ii) water; and (iii) the first mixture from step (a) while cooling the resulting second mixture to maintain the temperature thereof within a range of about 0-35*C., the mole ratio of primary amine to sulfuric acid being about 1:0.1-1.5 and the weight ratio of sulfuric acid, as H2SO4, to water being about 1:0.5-4; c. forming a third mixture by admixing hydrogen cyanide and the second mixture while cooling the resulting third mixture to maintain the temperature thereof within the range of about 0-35*C., the mole ratio of amine to hydrogen cyanide being about 1:1.8-2.5; d. forming the aminonitrile and a mother liquor by maintaining the third mixture under substantially adiabatic conditions in a closed reaction zone for about 10-300 minutes; and e. separating the aminonitrile from the mother liquor, and recovering the separated aminonitrile.