Method for processing contaminated wastewater from the preparation of isophorone, isophoronenitrile and isophoronediamine

Patent metadata

Field	Value
Publication number	US-10144662-B2
Application number	US-201514951117-A
Country	US
Kind code	B2
Filing date	Nov 24, 2015
Priority date	Nov 28, 2014
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

Contaminated wastewater from the preparation of isophorone, isophoronenitrile and isophoronediamine is treated by A) 1. treating the wastewater from the preparation of isophoronenitrile from the reaction of isophorone with hydrogen cyanide by alkaline hydrolysis of isophoronenitrile to isophorone, and the salts of hydrogen cyanide within a pH range of 12.0 to 13.7 and at temperatures of 60 to 200° C., and 2. processing the wastewater from A) 1. by an oxidation, or B) treating the wastewater from the preparation of isophoronenitrile from the reaction of isophorone with hydrogen cyanide by an oxidation, or C) processing the wastewater from A) 1. and the wastewater from the preparation of isophorone and/or the wastewater from the preparation of isophoronediamine by an oxidation.

First claim

The invention claimed is:

1. A method for processing contaminated wastewater from the preparation of isophorone, isophoronenitrile and/or isophoronediamine, the method comprising:
A) i) treating the wastewater, which comprises isophoronenitrile, said isophoronenitrile obtained from a reaction of isophorone with hydrogen cyanide, by alkaline hydrolysis to cleave isophoronenitrile into isophorone and a salt of hydrogen cyanide, wherein said alkaline hydrolysis is carried out within a pH range of 12.0 to 13.7 and at temperatures of 60 to 200° C. to obtain treated wastewater,
and
ii) processing the treated wastewater from A) i) by an oxidation.

2. A method for processing contaminated wastewater from the preparation of isophoronediamine, the method comprising:
I preparing isophorone by catalyzed aldol condensation with acetone as reactant,
II reacting isophorone with hydrogen cyanide to form isophoronenitrile,
III catalytically hydrogenating and/or catalytically reductively aminating isophoronenitrile to isophoronediamine,
IV treating wastewater from said II reacting, the wastewater comprising isophoronenitrile, by alkaline hydrolysis to cleave isophoronenitrile into isophorone and a salt of hydrogen cyanide, wherein said alkaline hydrolysis is carried out within a pH range from 12.5 to 13.7 at temperatures of 60 to 200° C. to obtain treated wastewater, and
V processing the treated wastewater from said IV treating by oxidation.

3. The method according to claim 1 or 2 , wherein the wastewater, prior to said A) i) treating or said IV treating, comprises isophoronenitrile and at least one member selected from the group consisting of isophorone, isophoronediamine, hydrogen cyanide, a salt of hydrogen cyanide, and an ammonium salt.

4. The method according to claim 1 or 2 , wherein, in said A) i) treating or said IV treating, the alkaline hydrolysis is effected at temperatures of 80 to 180° C.

5. The method according to claim 1 or 2 , wherein a product stream obtained from said A) i) treating or said IV treating has an isophoronenitrile content of not more than 5 mg/l.

6. The method according to claim 1 or 2 , wherein, in said A) i) treating or said IV treating, the isophorone formed is drawn off at the top of a hydrolysis column by distillation, together with another low boiler, and is fed back upstream to the method.

7. The method according to claim 1 or 2 , wherein, in said A) i) treating or said IV treating, at least one base is present, said base comprising at least one metal from column I and column II of the Periodic Table.

8. The method according to claim 1 or 2 , wherein the oxidation of A) ii) or V achieves a reduction in chemical oxygen demand for the treated wastewater, according to DIN 38409 H41, of at least 50%.

9. The method according to claim 1 or 2 , wherein at least one oxidizing agent selected from the group consisting of hydrogen peroxide; activated hydrogen peroxide which is activated by iron, UV or ozone; Caroat; sodium hypochlorite solution; hypochlorite produced in situ by chlorine injection; and chlorine dioxide, is present during the oxidation of A) ii) or V.

10. The method according to claim 1 or 2 , wherein the oxidation of A) ii) or V is conducted within a pH range between pH 11 and pH 5.

11. The method according to claim 1 or 2 , wherein the oxidation of A) ii) or V is conducted within a pH range between pH 11 and pH 5 in a cascade comprising 3 reactors in which different pH values are established.

12. The method according to claim 1 or 2 , wherein the oxidation of A) ii) or V is conducted within a temperature range between 10 and 50° C.

13. The method according to claim 1 or 2 , wherein, after said A) i) treating or said IV treating, the method further comprises:
subjecting the treated wastewater to a biological wastewater treatment method.

14. The method according to claim 1 or 2 , wherein the oxidation of A) ii) or V achieves a reduction in chemical oxygen demand for the treated wastewater, according to DIN 38409 H41, of at least 70%.

15. The method according to claim 1 or 2 , wherein NaOH is present during said alkaline hydrolysis.

Assignees

• Evonik Degussa Gmbh

Inventors

• Kreczinski Manfred
• Jansen Robert
• Woyciechowski Matthias

Classifications

• C02F2101/38

  containing nitrogen · CPC title

• C02F1/04

  by distillation or evaporation · CPC title

• C02F1/725

  by catalytic oxidation · CPC title

• C02F1/722

  Oxidation by peroxides · CPC title

• C02F2209/08

  Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD] · CPC title