Method of preparing solid-supported palladium catalyst

Patent metadata

Field	Value
Publication number	US-11980870-B2
Application number	US-202217929166-A
Country	US
Kind code	B2
Filing date	Sep 1, 2022
Priority date	Jan 2, 2020
Publication date	May 14, 2024
Grant date	May 14, 2024

Abstract

A solid-supported Pd catalyst is suitable for C—C bond formation, e.g., via Suzuki-Miyaura and Mizoroki-Heck cross-coupling reactions, with a support that is reusable, cost-efficient, regioselective, and naturally available. Such catalysts may contain Pd nanoparticles on jute plant sticks (GS), i.e., Pd@GS, and may be formed by reducing, e.g., K 2 PdCl 4 with NaBH 4 in water, and then used this as a “dip catalyst.” The dip catalyst can catalyze Suzuki-Miyaura and Mizoroki-Heck cross coupling-reactions in water. The catalysts may have a homogeneous distribution of Pd nanoparticles with average dimensions, e.g., within a range of 7 to 10 nm on the solid support. Suzuki-Miyaura cross-coupling reactions may achieve conversions of, e.g., 97% with TOFs around 4692 h −1 , Mizoroki-Heck reactions with conversions of, e.g., a 98% and TOFs of 237 h −1 , while the same catalyst sample may be used for 7 consecutive cycles, i.e., without addition of any fresh catalyst.

First claim

The invention claimed is:

1. A method of preparing a solid-supported palladium catalyst, the method comprising:
mixing a particulate matrix, comprising a-cellulose, hemicellulose, and lignin, with a palladium compound in an aqueous solution to form a suspension;
combining the suspension with a reducing agent to form a mixture; and
heating the mixture to thereby reduce at least 50 wt. % of the palladium compound, relative to total catalytic metal weight, and form the solid-supported palladium catalyst,
wherein particles of the particulate matrix have no average dimension less than 10 μm, and
wherein the lignin is present in the particulate matrix in a range of from 15 to 30 wt. % relative to total particulate matrix weight.

2. The method of claim 1 , wherein the reducing agent comprises a borohydride.

3. The method of claim 1 , wherein the reducing agent comprises NaBH 4 .

4. The method of claim 1 , wherein the palladium compound comprises palladium ion comprises a [PdCl 4 ] 2− anion.

5. The method of claim 1 , wherein the heating comprises treating the mixture at a temperature in a range of from 40 to 100° C., and/or
wherein the heating is conducted for a duration in the range of from 10 to 60 minutes.

6. The method of claim 1 , wherein the particulate matrix comprises at least 75 wt. % of the α-cellulose, hemicellulose, and lignin, based on the total particulate matrix weight, and
wherein palladium catalyst is disposed on the particulate matrix in an amount of from 0.01 to 1 wt. %, relative to a total weight of the solid-supported palladium catalyst, and
wherein the particulate matrix is in the form of particles having an average longest dimension of at least 1 μm.

7. The method of claim 6 , wherein the particles of the particulate matrix have no average dimension less than 100 μm.

8. The method of claim 6 , wherein the palladium catalyst is in the form of nanospheres having an average particle size in a range of from 2.5 to 45 nm.

9. The method of claim 8 , wherein the average particle size of the nanospheres is in a range of from 5 to 15 nm.

10. The method of claim 6 , wherein the α-cellulose, hemicellulose, and lignin, are from jute stems.

11. The method of claim 6 , wherein the particles of the particulate matrix comprise the α-cellulose in a range of from 20 to 60 wt. %, based on the total particulate matrix weight.

12. The method of claim 6 , wherein the particles of the particulate matrix comprise 10 to 30 wt. % hemicellulose, based on the total particulate matrix weight.

13. The method of claim 6 , wherein the particles of the particulate matrix comprise the α-cellulose in a range of from 30 to 50 wt. % and the hemicellulose in a range of from 15 to 25 wt.° 4 ), based on the total particulate matrix weight.

14. The method of claim 6 , wherein the particles of the particulate matrix comprise the jute stems in at least 90 wt. %, based on the total particulate matrix weight.

15. The method of claim 6 , wherein the palladium catalyst comprises the palladium in at least 90 wt. %, relative to a total metal weight in the palladium catalyst.

16. The method of claim 15 , wherein at least 90 at. % of the palladium is in an elemental state.

17. The method of claim 15 , wherein at least 97.5 at % of the palladium is in an elemental state.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Shaikh M Nasiruzzaman

Classifications

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J2235/10

  Infrared [IR] · CPC title

• B01J35/45

  Nanoparticles · CPC title

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title

• B01J35/393

  Metal or metal oxide crystallite size · CPC title