Bis[3-isopropenyl-α,α-dimethylbenzyl]carbodiimide, production methods, and use of said compound
The present invention relates to novel processes for producing bis[3-isopropenyl-α,α-dimethylbenzyl]carbodiimide, to the thus-produced bis[3-isopropenyl-α,α-dimethylbenzyl]carbodiimide and to the use thereof as a hydrolysis inhibitor in polyurethane (PU)-based systems, preferably thermoplastic TPU, PU adhesives, PU casting resins, PU elastomers or PU foams.
1. A process for producing bis[3-isopropenyl-α,α-dimethylbenzyl]carbodiimide, the process comprising carbodiimidizing 3-isopropenyl-α,α-dimethylbenzylisocyanate in the presence of 0.1-20 wt % of basic cesium salts at a temperature of 160° C. to 220° C.
2. The process as claimed in claim 1 , wherein the basic cesium salts comprise cesium carbonate and/or cesium alkoxide.
3. The process as claimed in claim 1 , further comprising filtering off the basic cesium salts following the carbodiimidization.
4. The process as claimed in claim 1 , further comprising conducting the carbodiimidization in a solvent.
5. The process as claimed in claim 4 , wherein the solvent comprises mono-, di-, tri- or polyalkyl-substituted benzenes and/or dibenzenes where alkyl C 1 -C 3 .
6. The process as claimed in claim 5 , wherein the alkyl-substituted benzenes are xylenes.
7. The process according to claim 1 , wherein the basic cesium salts are present at a concentration of 0.5 to 10 wt %, and the temperature is 180′C to 210° C.
8. The process according to claim 1 , wherein the process comprises:
carbodiimidizing 3-isopropenyl-α,α-dimethylbenzylisocyanate in the presence of:
0.1-20 wt % of cesium carbonate and/or cesium alkoxide, and
a solvent, at a temperature of 160° C. to 220° C. for a period of time sufficient for carbodiimidizetion of the 3-isopropenyl-α,α-dimethylbenzylisocyanate; and
filtering off the cesium carbonate and/or cesium alkoxide following the carbodiimidization.
9. The process according to claim 8 , wherein:
the carbodiimidizing is in the presence of cesium methoxide and/or cesium ethoxide;
the solvent is at least one xylene;
the basic cesium salts are present at a concentration of 1 to 5 wt %; and
the temperature is 190° C. to 200° C.
10. The process according to claim 1 , wherein the basic cesium salts comprise cesium carbonate and/or cesium methoxide and/or cesium ethoxide.