Multifunctional porous aramids (aerogels), fabrication thereof, and catalytic compositions derived therefrom

Patent metadata

Field	Value
Publication number	US-9593225-B2
Application number	US-201514969650-A
Country	US
Kind code	B2
Filing date	Dec 15, 2015
Priority date	Jun 4, 2012
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

The present disclosure provides a series of new and improved porous polyamide aerogels derived from multifunctional aromatics that combine the high mechanical strength of aramids with the pore structure of aerogels. The polyamide aerogels have a hyperbranched structure, relatively low density, high porosity and may be derived from functionalized monomers having more aromatic groups than functional groups. The present disclosure also provides a new method for producing the porous polyamide aerogels by polymerizing an aromatic multifunctional carboxylic acid or a ferrocene multifunctional carboxylic acid with a polyfunctional aromatic isocyanate at moderate reaction conditions followed by drying with liquid CO 2 . Also disclosed are various methods of use of these polyamide aerogels in a variety of applications, particularly in the generation of various precious metal catalysts. Thus, monolithic nanoporous carbon-supported Fe, Au, Pt, Pd, Co, Ni, Ru, and Rh catalysts are disclosed herein, which are derived by pyrolysis and transmetalation via galvanic replacement of ferrocene-based polyamide aerogels.

First claim

What is claimed is:

1. A composition of matter comprising a carbonizable polymeric aerogel incorporating ferrocene in every repeating unit, wherein said polymeric aerogel comprises the following repeating units:

wherein:
G represents a group selected from aryl, (aryl)-R-(aryl), and (aryl)-R-(aryl) 2 ; where each aryl independently represents an optionally substituted aromatic ring; and where R is a bond or a C 1 -C 6 straight chain or branched chain alkyl group;
G 2 represents a ferrocenyl moiety;
(*) denotes a linkage point; and

wherein the polymeric aerogel includes a mixture of polyamide and polyurea.

2. The polymeric aerogel of claim 1 wherein G is a triphenylmethane group of the following formula:

where the (*)s denote the linkage points on the linking bonds; and
where the linking bonds may be independently attached on their respective phenyl rings at the 2-position, 3-position or 4-position.

3. A process for carbonizing a carbonizable polymeric aerogel incorporating ferrocene in every repeating unit, wherein said polymeric aerogel comprises the following repeating units:

wherein:
G represents a group selected from awl, (aryl)-R-(aryl), and (aryl)-R-(aryl) 2 ; where each aryl independently represents an optionally substituted aromatic ring; and where R is a bond or a C 1 -C 6 straight chain or branched chain alkyl group;
G 2 represents a ferrocenyl moiety;
(*) denotes a linkage point; and,

wherein the polymeric aerogel includes a mixture of polyamide and polyurea;
said process comprising the step of pyrolizing the polymeric aerogel at temperatures in the range 500-2300° C. to yield a nanoporous product that includes iron-doped carbon-monoliths containing Fe(0) nanoparticles in graphitic pockets dispersed throughout the 3D matrix of monolithic nanoporous carbon.

4. A process for partially or completely transmetalating the iron-doped carbon-monoliths of claim 3 to produce M-doped carbon monoliths, wherein M is one or more metals selected from the group of metals consisting of Fe, Au, Pt, Pd, Co, Ni, Ru, and Rh, said process comprising the step of dipping the iron-doped carbon monoliths in solutions of the respective metal ions.

5. The process of claim 4 , further including the step of subjecting the solutions of the respective metal ions to galvanic conditions.

6. A composition of matter comprising M-doped carbon monoliths obtained by the following process steps:
(a) carbonizing a polymeric aerogel incorporating ferrocene in every repeating unit by pyrolizing said polymeric aerogel at temperatures in the range 500-2300° C. to yield a nanoporous product that includes iron-doped carbon-monoliths containing Fe(0) nanoparticles in graphitic pockets dispersed throughout a 3D matrix of monolithic nanoporous carbon; and,
(b) partially or completely transmetalating the iron-doped carbon-monoliths by dipping the nanoporous product that includes the iron-doped carbon monoliths in solutions of metal ions to produce the M-doped carbon monoliths;
wherein M is one or more metals selected from the group of metals consisting of Fe, Au, Pt, Pd, Co, Ni, Ru, and Rh;
wherein said polymeric aerogel comprises the following repeating units:

wherein:
G represents a group selected from aryl, (aryl)-R-(aryl), and (aryl)-R-(aryl) 2 ; where each aryl independently represents an optionally substituted aromatic ring; and where R is a bond or a C 1 -C 6 straight chain or branched chain alkyl group;
G 2 represents a ferrocenyl moiety;
(*) denotes a linkage point and,

wherein the polymeric aerogel includes a mixture of polyamide and polyurea.

7. The composition of claim 6 wherein the composition includes at least 50% v/v porous materials consisting of at least 50% w/w of carbon.

8. The composition of claim 7 , wherein the carbon includes a substantial amount of disordered graphite, and contains in dispersed form nanoparticles of metal M in a w/w ratio of from about 1% to about 50%.

9. A method of catalysis of a chemical reaction in a mixture, the method comprising the step of contacting the mixture with a catalytic amount of a composition of matter comprising M-doped carbon monoliths obtained by the following steps:
(a) carbonizing a polymeric aerogel incorporating ferrocene in every repeating unit by pyrolizing said polymeric aerogel at temperatures in the range 500-2300° C. to yield a nanoporous product that includes iron-doped carbon-monoliths containing Fe(0) nanoparticles in graphitic pockets dispersed throughout a 3D matrix of monolithic nanoporous carbon; and,
(b) partially or completely transmetalating the iron-doped carbon-monoliths by dipping the nanoporous product that includes the iron-doped carbon monoliths in solutions of metal ions to produce the M-doped carbon monoliths;
wherein M is one or more metals selected from the group of metals consisting of Fe, Au, Pt, Pd, Co, Ni, Ru, and Rh; and, wherein said polymeric aerogel comprises the following repeating units:

wherein:
G represents a group selected from awl, (aryl)-R-(aryl), and (aryl)-R-(aryl) 2 ; where each aryl independently represents an optionally substituted aromatic ring; and where R is a bond or a C 1 -C 6 straight chain or branched chain alkyl group;
G 2 represents a ferrocenyl moiety;
(*) denotes a linkage point and,

wherein the polymeric aerogel includes a mixture of polyamide and polyurea.

10. The method of claim 9 , wherein the chemical reaction is selected from the group consisting of reduction of a nitro compound, oxidation of an alcohol, and a Heck coupling reaction.

Assignees

• Univ Missouri

Inventors

• Leventis Nicholas
• Sotiriou-Leventis Chariklia
• Saeed Malik Adnan

Classifications

• C01B31/00

  Chemistry & Metallurgy · mapped topic

• B01J23/42

  Platinum · CPC title

• B01J23/52

  Gold · CPC title

• C07C67/10

  by reacting carboxylic acids or symmetrical anhydrides with ester groups or with a carbon-halogen bond (preparation from carboxylic acid halides C07C67/14) · CPC title

• B01J13/0091

  Preparation of aerogels, e.g. xerogels · CPC title