Processes for removing carbon disulfide from symmetrical and asymmetrical sulfide product streams

Patent metadata

Field	Value
Publication number	US-10774040-B1
Application number	US-201916396820-A
Country	US
Kind code	B1
Filing date	Apr 29, 2019
Priority date	Apr 29, 2019
Publication date	Sep 15, 2020
Grant date	Sep 15, 2020

Abstract

Processes for removing carbon disulfide from product streams containing a sulfide compound are performed by contacting the product stream with an alkanolamine and converting the carbon disulfide to a higher boiling point product, thereby reducing or eliminating carbon disulfide from the product stream. Subsequent removal of the higher boiling point product via distillation can lead to a purified sulfide stream with high purity.

First claim

We claim:

1. A process to purify a product stream containing a sulfide compound and CS 2 , the process comprising:
(i) contacting the product stream with an alkanolamine to convert at least a portion of the CS 2 to a higher boiling point product, wherein the product stream contains at least about 80 wt. % of the sulfide compound; and
(ii) removing at least a portion of the higher boiling point product from the product stream to form a purified sulfide stream.

2. The process of claim 1 , wherein the sulfide compound has formula (I):
R 1 —S—R 2   (I);

wherein R 1 and R 2 independently are a C 1 to C 18 substituted or unsubstituted, cycloalkyl group or linear or branched alkyl group.

3. The process of claim 2 , wherein R 1 and R 2 independently are a C 1 to C 12 alkyl group.

4. The process of claim 1 , wherein the sulfide compound is methyl ethyl sulfide or dimethyl sulfide.

5. The process of claim 1 , wherein the product stream contains:
at least about 99 wt. % of the sulfide compound; and
at least about 500 ppm of CS 2 .

6. The process of claim 1 , wherein the alkanolamine is a C 2 to C 6 alkanolamine.

7. The process of claim 1 , wherein the alkanolamine is a monoalkanolamine selected from methanolamine, ethanolamine, n-propanolamine, isopropanolamine, n-butanolamine, isobutanolamine, or any combination thereof.

8. The process of claim 1 , wherein the alkanolamine is a dialkanolamine or a trialkanolamine.

9. The process of claim 1 , wherein the alkanolamine comprises a heteroatom-containing linking group between the hydroxy and the amine group.

10. The process of claim 1 , wherein the alkanolamine is a β-hydroxy amine having formula (II):

wherein R 3 , R 4 , R 5 , and R 6 independently are H or a C 1 to C 12 alkyl group.

11. The process of claim 1 , wherein the higher boiling point product comprises a heterocyclic organic compound.

12. The process of claim 1 , wherein:
a molar ratio of alkanolamine:CS 2 in step (i) is in a range from about 1.5:1 to about 10:1; and
an amount of the alkanolamine contacted with the product stream is in a range from about 0.1 wt. % to about 2 wt. %, based on the weight of the product stream.

13. The process of claim 1 , wherein in step (i):
the product stream is contacted with the alkanolamine in an alcohol diluent; and
a weight ratio of alkanolamine:diluent is in a range from about 95:5 to about 25:75.

14. The process of claim 1 , wherein:
at least about 95 wt. % of the CS 2 in the product stream is converted to the higher boiling point product; and
the higher boiling point product has a boiling point at least 30° C. greater than the boiling point of the sulfide compound.

15. The process of claim 1 , wherein in step (ii), the higher boiling point product is removed from the product stream using distillation to form the purified sulfide stream.

16. The process of claim 1 , wherein the purified sulfide stream contains:
at least about 99.9 wt. % of the sulfide compound; and
less than or equal to about 75 ppm of CS 2 .

17. The process of claim 1 , wherein:
the sulfide compound is dimethyl sulfide;
the alkanolamine is ethanolamine;
a molar ratio of ethanolamine:CS 2 in step (i) is in a range from about 2:1 to about 6:1;
an amount of the ethanolamine contacted with the product stream is in a range from about 0.4 wt. % to about 1.5 wt. %, based on the weight of the product stream; and
the purified sulfide stream contains less than or equal to about 25 ppm of CS 2 .

18. The process of claim 1 , wherein:
at least about 95 wt. % of the higher boiling point product is removed from the product stream to form the purified sulfide stream; and
a ratio of a ppm concentration of CS 2 in the product stream prior to step (i) to a ppm concentration of CS 2 in the purified sulfide stream is at least about 100:1.

19. The process of claim 1 , further comprising the steps of:
(a) determining a concentration of the CS 2 in the product stream; and
(b) adjusting an amount of the alkanolamine contacted with the product stream based on the concentration of the CS 2 in the product stream.

20. The process of claim 1 , further comprising the steps of:
(A) determining a concentration of the CS 2 in the purified sulfide stream; and
(B) adjusting an amount of the alkanolamine contacted with the product stream based on the concentration of the CS 2 in the purified sulfide stream.

21. A process to purify a product stream containing a sulfide compound and CS 2 , the process comprising:
(i) contacting the product stream with an alkanolamine to convert at least a portion of the CS 2 to a higher boiling point product, wherein the product stream contains:
at least about 95 wt. % of the sulfide compound; and
from about 250 ppm to about 5000 ppm of CS 2 ; and

(ii) removing at least a portion of the higher boiling point product from the product stream to form a purified sulfide stream.

22. The process of claim 21 , wherein:
the sulfide compound is dimethyl sulfide;
the alkanolamine is ethanolamine;
in step (ii), the higher boiling point product is removed from the product stream using distillation to form the purified sulfide stream; and
the purified sulfide stream contains less than or equal to about 75 ppm of CS 2 .

23. The process of claim 22 , wherein:
a molar ratio of ethanolamine:CS 2 in step (i) is in a range from about 1.5:1 to about 10:1, and/or an amount of the ethanolamine contacted with the product stream is in a range from about 0.1 wt. % to about 2 wt. %, based on the weight of the product stream; and
the purified sulfide stream contains at least about 99.9 wt. % of dimethyl sulfide and less than or equal to about 25 ppm of CS 2 .

24. The process of claim 21 , further comprising the steps of:
(a) determining a concentration of the CS 2 in the product stream; and
(b) adjusting an amount of the alkanolamine contacted with the product stream based on the concentration of the CS 2 in the product stream; or
(A) determining a concentration of the CS 2 in the purified sulfide stream; and
(B) adjusting an amount of the alkanolamine contacted with the product stream based on the concentration of the CS 2 in the purified sulfide stream; or
both.

25. The process of claim 21 , wherein a ratio of the ppm concentration of CS 2 in the product stream prior to step (i) to a ppm concentration of CS 2 in the purified sulfide stream is at least about 250:1.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Lassen Kenneth M
• Matson Michael S
• Hasenberg Daniel M
• Schwierman Dave

Classifications

• C07D227/04

  with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, attached to ring carbon atoms · CPC title

• C07C319/28 Primary

  Separation; Purification · CPC title

• B01D3/009

  in combination with chemical reactions · CPC title

• B01J8/02

  with stationary particles, e.g. in fixed beds · CPC title

• C07C319/06

  from sulfides, hydropolysulfides or polysulfides · CPC title