Process for preparing eda using so2-free hydrocyanic acid

Patent metadata

Field	Value
Publication number	US-2016009633-A1
Application number	US-201414771409-A
Country	US
Kind code	A1
Filing date	Feb 12, 2014
Priority date	Feb 28, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

The present invention relates to a process for preparing ethylenediamine (EDA), where the process comprises the steps a) to c). In step a), formaldehyde is reacted with hydrocyanic acid (HCN) to form formaldehyde cyanohydrin (FACH), where the hydrocyanic acid is completely free or largely free of sulfur dioxide (SO 2 ). The FACH prepared in this way is reacted with ammonia (NH 3 ) to form aminoacetonitrile (AAN) in step b), whereupon a hydrogenation of AAN in the presence of a catalyst to form EDA is carried out in step c).

First claim

1 . A process for preparing ethylenediamine (EDA), comprising:
a) reacting formaldehyde and hydrocyanic acid (HCN) to form formaldehyde cyanohydrin (FACH), wherein the hydrocyanic acid is completely free or largely free of sulfur dioxide (SO 2 ), b) reacting the FACH with ammonia (NH 3 ) to form aminoacetonitrile (AAN), c) hydrogenating the AAN in the presence of a catalyst to yield a hydrogenation product comprising the EDA.

2 . The process according to claim 1 , wherein in a), the molar ratio of HCN to formaldehyde of 0.85 to 1.00:1 [mol/mol] or the formaldehyde is an aqueous formaldehyde having a formaldehyde content of 20% to 60% by weight.

3 . The process according to claim 1 , wherein in b), the molar ratio of FACH to ammonia is 1:2 to 1:50 [mol/mol].

4 . The process according to claim 1 , wherein the pressure in b) is so high that a reaction mixture formed in b) is in liquid form.

5 . The process according to claim 1 , wherein the catalyst is a Raney catalyst.

6 . The process according to claim 1 , wherein in c), the space velocity over the catalyst is 0.1 gram to 3 gram of AAN per gram of the catalyst an hour.

7 . The process according to claim 1 , wherein the catalyst has a BET surface area of 10 m 2 to 100 m 2 per gram of the catalyst.

8 . The process according to claim 1 , wherein in c), the temperature is 20° C. to 150° C. or the pressure is 40 bar to 400 bar.

9 . The process according to claim 1 , wherein, the AAN formed in b) is
i) hydrogenated in c) without prior work-up by distillation and/or without removal of water, or ii) subjected to an adsorptive purification with an ion exchanger or a metal oxide before being hydrogenated in c).

10 . The process according to claim 1 , further comprising:
d) removing ammonia from the hydrogenation product after c).

11 . The process according to claim 10 , wherein d) is carried out in two stages, wherein:
in the first stage, ammonia is taken off at 20° C. to 70° C. at the top of a first column and condensed out to produce an NH 3 -depleted stream and an NH 3 -comprising stream, and the NH 3 -depleted stream is transferred from the bottom of the first column having a temperature of less than 220° C. to a second column, in the second stage, EDA is separated from the NH 3 -depleted stream at the bottom of the second column and the NH 3 -comprising stream is optionally recirculated to the first column, wherein the EDA is largely free of ammonia.

12 . The process according to claim 10 , wherein the ammonia removed is recirculated from d) to b).

13 . The process according to claim 1 , further comprising:
removing water from the hydrogenation product after c).

14 . The process according to claim 1 , further comprising:
separating the EDA from the hydrogenation product by distillation after c).

15 . The process according to claim 1 , wherein the catalyst is a Raney cobalt catalyst comprising: Al: 2-6% by weight, Co: ≧86% by weight, Fe: 0-1% by weight, Ni: 1-4% by weight, Cr: 1.5-3.5% by weight is used in step c).

16 . The process according to claim 1 , wherein the pressure in b) is higher than the pressure in c).

17 . The process according to claim 5 , wherein the Raney catalyst is a Raney nickel catalyst or a Raney cobalt catalyst.

18 . The process according to claim 17 , wherein the Raney cobalt catalyst comprises one or more promoters selected from the group consisting of Fe, Ni and Cr.

19 . The process according to claim 1 , wherein the catalyst has a BET surface of 20 m 2 to 500 m 2 per gram of the catalyst.

20 . The process according to claim 10 , further comprising:
removing water from the hydrogenation product after d).

21 . The process according to claim 10 , further comprising:
separating the EDA from the hydrogenation product by distillation after d).

22 . The process according to claim 1 , wherein the HCN has a sulfur dioxide content of less than 10 ppm.

Assignees

• Basf Se

Inventors

• Luyken Hermann
• Jaegli Stephanie
• Lorenz Michael
• Brasche Gordon
• Jegelka Markus
• Becker Barbara
• Baumann Robert
• Melder Johann-Peter
• Buschhaus Boris
• Krug Thomas

Classifications

• C07C253/00

  Preparation of carboxylic acid nitriles (of cyanogen or compounds thereof C01C3/00) · CPC title

• C07C253/30

  by reactions not involving the formation of cyano groups · CPC title

• C07C209/48 Primary

  by reduction of nitriles · CPC title

• C07C253/08

  by addition of hydrogen cyanide or salts thereof to unsaturated compounds · CPC title

• C07C209/86

  Separation · CPC title