Process for preparing acrylic acid

Patent metadata

Field	Value
Publication number	US-9695099-B2
Application number	US-201514956800-A
Country	US
Kind code	B2
Filing date	Dec 2, 2015
Priority date	Dec 2, 2014
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

The present invention relates to a process for preparing acrylic acid from acetic acid and formaldehyde, which comprises (a) provision of a stream S 1 comprising acetic acid and formaldehyde, where the molar ratio of acetic acid to formaldehyde in the stream S 1 is in the range from 0.5:1 to 2:1; (b) contacting of the stream S 1 with an aldol condensation catalyst comprising vanadium, phosphorus and oxygen to give a stream S 2 comprising acrylic acid, where, in (b), the space velocity WHSV is in the range from 0.35 to 7.0 kg/kg/h.

First claim

The invention claimed is:

1. A process for preparing acrylic acid from acetic acid and formaldehyde, the process comprising:
(a) providing a stream S 1 comprising acetic acid and formaldehyde, where a molar ratio of acetic acid to formaldehyde in the stream S 1 is from 0.5:1 to 2:1;
(b) contacting the stream S 1 with an aldol condensation catalyst comprising vanadium, phosphorus and oxygen to give a stream S 2 comprising acrylic acid,
wherein, in (b), a space velocity WHSV, defined ([Formaldehyde]+[acetic acid])/[aldol condensation catalyst]/time, is from 0.75 to 3.5 kg/kg/h, wherein [formaldehyde], [acetic acid], and [aldol condensation catalyst] represent mass of formaldehyde, acetic acid, and the aldol condensation catalyst, respectively, and wherein the aldol condensation catalyst in (b) comprises SiO 2 as a support material.

2. The process according to claim 1 , wherein the content of vanadium in the aldol condensation catalyst as per (b) is from 2 to 20% by weight, the content of phosphorus is from 2 to 20% by weight, and the content of oxygen is from 20 to 60% by weight, in each case based on the total weight of the aldol condensation catalyst.

3. The process according to claim 1 , wherein the aldol condensation catalyst in (b) additionally comprises at least one further element M selected from the group consisting of Bi, W, Sn, Ti, Fe, Mn, Cr, Cu, K, Cs, Li, Mg and Ca.

4. The process according to claim 1 , wherein the aldol condensation catalyst in (b) is present as a powder.

5. The process according to claim 1 , wherein the aldol condensation catalyst in (b)
does not comprise other elements in addition to vanadium, phosphorus and oxygen,
has a molar ratio of vanadium to phosphorus of from 1:2 to 1:1.75, and
the content of vanadium is from 5.6 to 6.2% by weight, the content of phosphorus is from 6.8 to 7.4% by weight, the content of oxygen is from 55 to 60% by weight, and the content of silicon is from 28 to 30% by weight, in each case based on the total weight of the aldol condensation catalyst.

6. The process according to claim 1 , wherein the aldol condensation catalyst in (b)
does not comprise other elements in addition to vanadium, phosphorus and oxygen,
has a molar ratio of vanadium to phosphorus of from 1:2 to 1:1.75, and
the content of vanadium is from 6.3 to 6.9% by weight, the content of phosphorus is from 7.5 to 8.1% by weight, the content of oxygen is from 50 to 55% by weight, and the content of silicon is from 31 to 33% by weight, in each case based on the total weight of the aldol condensation catalyst.

7. The process according to claim 1 , wherein the aldol condensation catalyst in (b)
comprises vanadium, phosphorus, oxygen, tungsten, and bismuth,
has a molar ratio of (V+W+Bi) to phosphorus of from 1.75:1 to 2.25:1, and
the content of vanadium is from 10 to 13% by weight, the content of phosphorus is from 5 to 7% by weight, the content of oxygen is from 35 to 40% by weight, the content of bismuth is from 7 to 10% by weight, the content of tungsten is from 7 to 10% by weight, and the content of silicon is from 4 to 7% by weight, in each case based on the total weight of the aldol condensation catalyst.

8. The process according to claim 1 , wherein the molar ratio of acetic acid to formaldehyde in the stream S 1 is from 0.75:1 to 1.5:1.

9. The process according to claim 1 , wherein the stream S 1 comprises at least one further component in addition to acetic acid and formaldehyde.

10. The process according to claim 9 , wherein the at least one further component is selected from the group consisting of water, oxygen and an inert gas.

11. The process according to claim 10 , wherein the stream S 1 comprises from 50 to 100% by volume of acetic acid, formaldehyde, water, oxygen and the inert gas.

12. The process according to claim 9 , wherein the stream S 1 additionally comprises propionic acid.

13. The process according to claim 1 , wherein the contacting (b) is carried out at a temperature of the catalyst bed of more than 320° C.

14. The process according to claim 1 , wherein the stream S 2 comprises propionic acid of not more than 2500 ppm by weight based on the acrylic acid comprised in S 2 .

15. The process according to claim 10 , wherein the stream S 1 additionally comprises propionic acid.

Assignees

• Basf Se

Inventors

• Liu Yong
• Dieterle Martin
• Woerz Nicolai Tonio
• Parvulescu Andrei-Nicolae
• Lejkowski Michael
• Lieberknecht Johannes
• Walsdorff Christian
• Amakawa Kazuhiko

Classifications

• B01J23/002

  Mixed oxides other than spinels, e.g. perovskite · CPC title

• B01J2523/00

  Constitutive chemical elements of heterogeneous catalysts · CPC title

• B01J37/0213

  Preparation of the impregnating solution · CPC title

• B01J37/0203

  the impregnation liquid containing organic compounds · CPC title

• B01J29/7057

  Zeolite Beta · CPC title