Method for manufacturing compounds including nitrile functions
A process for the preparation of compounds containing nitrile functions and, more specifically, compounds containing two nitrile functions, such as succinonitrile and adiponitrile, is described. A process for preparing dintrile compounds obtained by reacting ammonia with an aqueous solution of a dicarboxyl compound in the presence of a silicon orthophosphate catalyst is also described.
1. A process for preparing a compound, the process comprising preparing the compound to have a general formula I
(NC) x —R 1 (CN) y (1)
in which:
R 1 represents a saturated or unsaturated, linear or branched hydrocarbon group containing 1 to 20 carbon atoms and optionally containing hetero-atoms,
x and y are 0 or 1, with (x+y) being 1 or 2,
by reacting ammoniac with a compound of general formula II
(H 4 NOOC) x —(R 1 )—(COONH) y
in vapour phase in the presence of a catalyst comprising a silicon ortho phosphate of formula Si 3 (PO 4 ) 4 , at a temperature of between 300° C. and 450° C.
2. The process according to claim 1 , wherein the compound of general formula II is in aqueous solution.
3. The process according to claim 2 , wherein the compound of general formula II in the aqueous solution is present in a concentration of greater than 1% by weight.
4. The process according to claim 3 , wherein the compound of general formula II in the aqueous solution is present in a concentration of between 1% and 30% by weight.
5. The process according to claim 2 , wherein the aqueous solution of the compound of general formula II is a medium resulting from a biological transformation of a sugar compound.
6. The process according to claim 5 , wherein the medium obtained from the biological transformation that is used is obtained after separation from a biomass.
7. The process according to claim 1 , wherein the compound of general formula II is selected from the group consisting of ammonium succinate, ammonium adipate, ammonium glutamate, ammonium glutarate, ammonium salts of fatty diacids, ammonium hexadecanedioate and combinations thereof.
8. The process according to claim 1 , wherein the reaction is performed in a reactor comprising a fixed catalyst bed.
9. The process according to claim 1 , wherein the catalyst is obtained by impregnating a silica with phosphoric acid and calcining in air.
10. The process according to claim 9 , wherein the calcining is performed at a temperature of between 400° C. and 800° C.
11. The process according to any of the claim 1 , wherein the compound of general formula I is selected from the group consisting of adiponitrile and succinonitrile.
12. The process according to claim 4 , wherein the concentration of the compound of the general formula II in the aqueous solution is between 1% and 2% by weight.