Addition of severely-hindered aminoacids to severely-hindered amines for the absorption of H.sub.2 S

• US 4,895,670 A
• Filed: 10/13/1987
• Issued: 01/23/1990
• Est. Priority Date: 10/13/1987
• Status: Expired due to Fees

• Current Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Original Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Inventors: Sartori, Guido, Ho, W. S. Winston
• Primary Examiner(s): Rotman, Alan L.
• Assistant Examiner(s): SCALZO, CATHERINE KILBY
• Application Number:
  US07/106,795
• Time in Patent Office: 833 Days
• Field of Search: 252/189, 252/190, 252/191
• US Class Current: 252/189
• CPC Class Codes: B01D 53/1493 Selection of liquid materials for use as absorbents

Abstract

A new alkaline absorbent solution containing a severely-hindered amine and a severely-hindered aminoacid is provided. A process for the removal of H₂ S from fluid mixtures using this absorbent solution to produce a very low level of H₂ S in the treated fluid is also provided. The process is also suitable for the selective removal of H₂ S from fluid mixtures comprising H₂ S and CO₂. Use of the above absorbent solution leads to higher selectivity for H₂ S than observed when the severely-hindered amine is used alone without the severely-hindered aminoacid.

Claims

1. A composition comprising:

(1) at least one severely hindered amino compound having a cumulative -E_s value (Taft'"'"'s steric hindrance constant) greater than 1.75 wherein said severely hindered amino compound is selected from the group consisting of a secondary amino ether alcohol, a di-secondary amino ether, and mixtures thereof, and (2) an aminoacid, said aminoacid being a severely hindered amino compound having a cumulative -E_s value greater than 1.75, wherein said aminoacid is selected from the group consisting of N-tertiarybutylalanine, N-tertiarybutylglycine, and mixtures thereof, said aminoacid and said severely hindered amino compound being present in said absorbent composition in a mole ratio of said aminoacid to said severely hindered amino compound of about 0.01;

1 to 4;

1.

2. The composition of claim 1 wherein said absorbent composition additionally comprises a liquid selected from the group consisting of water, an organic solvent and mixtures thereof.

3. The composition of claim 1 wherein said mole ratio of said aminoacid to said severely hindered amino compound ranges from about 0.3:

1 to 1;

1.

4. The composition of claim 1 wherein said absorbent composition comprises from about 5 to 70 wt% of said severely hindered amino compound, from about 1 to 70 weight percent of said aminoacid and the balance being water.