Diamino-alcohol compounds and processes for their manufacture
View Patent ↗A new class of compounds, namely diamino alcohols, is described, along with a process for their production and their use as dispersing additives for coating formulations.
1. A process for the production of a diamino polyol compound having the formula:
wherein each of the two amino (—NH 2 ) groups is bonded to a tertiary atom, R and R 3 are the same as each other and are each a, alkyl, aryl, or —CH 2 OH; R 1 and R 4 are the same as each other and are each, alkyl, aryl, or —CH 2 OH; alternatively, R and R 1 may be linked together to form a cycloalkyl; R 2 is independently alkyl, or phenyl; and alternatively, R 3 and R 4 may be linked together to form a cycloalkyl, said process comprising:
(A)(i) reacting (1) a primary nitroalkane and (2) an α, β-unstaturated aldehyde, at a molar ratio of 2:1, and in the presence of an organic catalyst, and under conditions in which Michael addition and nitro-aldol (Henry) reaction, between the (1) primary nitroalkane and the (2) α,β-unsaturated aldehyde, occur sequentially, Michael reaction first, to form a dinitro alcohol;
(A)(ii) further reacting the resulting dinitro alcohol with (3) an aldehyde to form a dinitro poly-alcohol compound; and
(B) reducing the dinitro poly-alcohol compound of step (A)(ii) to the corresponding diamino polyol under hydrogenation conditions, in the presence of a catalyst.
2. The process according to claim 1 , wherein the catalyst used in said hydrogenation (B) step comprises Raney nickel.
3. The process according to claim 1 , wherein the (1) primary nitroalkane is nitroethane or 1-nitropropane or nitromethane, followed by reaction with (3) formaldehyde.