Optimized separation technique for work-up of homogeneously catalysed hydroformylation mixtures

Patent metadata

Field	Value
Publication number	US-10017443-B2
Application number	US-201414770525-A
Country	US
Kind code	B2
Filing date	Feb 13, 2014
Priority date	Feb 26, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

The invention relates to a method for producing alcohols by homogeneously catalyzed hydroformylation of olefins to aldehydes and subsequent hydration of the aldehydes. The invention further relates to a system for carrying out the method. The main focus is on the separation technique for work-up of the hydroformylation mixture. The problem addressed by the invention is that specifying a work-up method for hydroformylation mixtures that utilizes the specific advantages of known separation technologies but at the same time largely avoids the specific disadvantages of said separation technologies. The most important objective is to create a catalyst separation system that is as complete and at the same time conservative as possible and that operates in a technically reliable manner and entails low investment and operating costs. The method should be unrestrictedly suitable for processing the reaction output from oxo systems in “world scale” format. The problem is solved by combining membrane separation units and a thermal separation unit, the thermal separation unit being operated in such a manner that 80% to 98% of the mass introduced with the product stream into the thermal separation unit exits the thermal separation unit again as a head product.

First claim

The invention claimed is:

1. A process for producing an alcohol, the process comprising:
a) providing at least one olefin, syngas and a catalyst system and optionally a solvent;
b) hydroformylating the olefin in the presence of the syngas and of the catalyst system in at least one hydroformylation reactor in a homogeneously catalysed hydroformulation to form at least one aldehyde and at least one high boiler;
c) withdrawing a liquid hydroformylation effluent comprising the aldehyde, the olefin, dissolved syngas, the catalyst system and the high boiler from the hydroformylation reactor;
d) optionally devolatilizing the liquid hydroformylation effluent;
e) separating the liquid hydroformylation effluent in a first membrane separation unit into a product stream and a reactor return stream, wherein the catalyst system partitions into the reactor return stream;
f) returning the reactor return stream into the hydroformylation reactor;
g) optionally devolatilizing the product stream;
h) separating the product stream in a thermal separation unit into a gaseous head product comprising a first part of the aldehyde and the olefin and a liquid bottom product comprising a second part of the aldehyde, the high boiler and a catalyst complex; and
i) separating the liquid bottom product in a second membrane separation unit into a permeate and a retentate, wherein the catalyst system partitions into the retentate; and wherein an improvement of the process comprises:
(j) operating the thermal separation unit such that 80% to 98% of mass introduced into the thermal separation unit with the product stream re-emerges from the thermal separation unit as head product;
(k) subjecting at least some of the head product of the thermal separation unit and the permeate of the second membrane separation unit to conjoint or separate hydrogenation; and
(l) the second membrane separation unit takes a form of a two-stage enriching cascade.

2. The process according to claim 1 , wherein the retentate of the second membrane separation unit is fed to the first membrane separation unit in admixture with the liquid hydroformylation effluent withdrawn from the hydroformylation reactor.

3. The process according to claim 1 , wherein the permeate of the second membrane separation unit passes through an adsorber before the hydrogenation.

4. The process according to claim 1 , wherein the head product of the thermal separation unit passes through an adsorber before the hydrogenation.

5. The process according to claim 3 , wherein the head product of the thermal separation unit and the permeate of the second membrane separation unit pass through the same adsorber before the hydrogenation.

6. The process according to claim 5 , wherein the head product of the thermal separation unit and the permeate of the second membrane separation unit are subject to the conjoint hydrogenation.

7. The process according to claim 1 , wherein a hydrogenation mixture is withdrawn from the hydrogenation and subjected to a thermal work-up to obtain an alcohol-rich fraction, a low-boiler fraction and a high-boiler fraction.

8. The process according to claim 1 , wherein the thermal separation unit comprises a thin film evaporator and a falling film evaporator, the thin film evaporator and the falling film evaporator being serially interconnected, optionally with the thin film evaporator being serially connected downstream of the falling film evaporator.

9. The process according to claim 1 , wherein the thermal separation unit comprises two or three serially interconnected falling film evaporators.

10. The process according to claim 1 , wherein the first membrane separation unit takes a form of a two-stage depleting cascade.

11. The process according to claim 1 , wherein the catalyst system comprises a rhodium catalyst comprising an organophosphorus ligand, the ligand being selected from the group consisting of a phosphite, a phosphine and a phosphoramidite.

12. The process according to claim 1 , wherein the olefin comprises eight carbon atoms and is hydroformylated to the aldehyde comprising nine carbon atoms, and the aldehyde is hydrogenated to an alcohol comprising nine carbon atoms.

13. A plant, comprising:
a) at least one hydroformylation reactor comprising a reactant inlet and a product outlet;
b) a first membrane separation unit comprising a first membrane entry point, a first permeate connection point and a first retentate connection point;
c) a thermal separation unit comprising a product inlet, a head product connection point and a bottom product connection point;
d) a second membrane separation unit comprising a second membrane entry point, a second permeate connection point and a second retentate connection point;
e) at least one hydrogenation reactor comprising an aldehyde entry point and an alcohol exit point;
wherein
the product outlet of the hydroformylation reactor connects directly or via a devolatilizer to the first membrane entry point of the first membrane separation unit;
the first retentate connection point of the first membrane separation unit connects to the reactant inlet of the hydroformylation reactor;
the first permeate connection point of the first membrane separation unit connects directly or via a devolatilizer to the product inlet of the thermal separation unit;
the bottom product connection point of the thermal separation unit connects to the second membrane entry point of the second membrane separation unit;
the head product connection point of the thermal separation unit connects directly or via an adsorber to the aldehyde entry point of the hydrogenation reactor;
the second retentate connection point of the second membrane separation unit connects together with the product outlet of the hydroformylation reactor to the first entry point of the first membrane separation unit;
the second permeate connection point of the second membrane separation unit connects directly or via the adsorber to the aldehyde entry point of the hydrogenation reactor; and
the second membrane separation unit takes a form of a two-stage enriching cascade.

14. The process according to claim 1 , which is carried out in a plant comprising:
a) the at least one hydroformylation reactor comprising a reactant inlet and a product outlet;
b) the first membrane separation unit comprising a first membrane entry point, a first permeate connection point and a first retentate connection point;
c) the thermal separation unit comprising a product inlet, a head product connection point and a bottom product connection point;
d) the second membrane separation unit comprising a second membrane entry point, a second permeate connection point and a second retentate connection point;
e) at least one hydrogenation reactor comprising an aldehyde entry point and an alcohol exit point;
wherein
the product outlet of the hydroformylation reactor connects directly or via a devolatilizer to the first membrane entry point of the first membrane separation unit;
the first retentate connection point of the first membrane separation unit connects to the reactant inlet of the hydroformylation reactor;

the first permeate connection point of the first membrane separation unit connects directly or via a devolatilizer to the product inlet of the thermal separation unit;
the bottom product connection point of the thermal separation unit connects to the second membrane entry point of the second membrane separation unit;
the head product connection point of the thermal separation unit connects directly or via an adsorber to the aldehyde entry point of the hydrogenation reactor;
the second retentate c

Assignees

• Lueken Hans Gerd
• Hamers Bart
• Fridag Dirk
• Franke Robert
• Priske Markus
• Hess Dieter
• Becker Marc
• Rudek Markus
• Evonik Degussa Gmbh

Inventors

• Lueken Hans-Gerd
• Hamers Bart
• Fridag Dirk
• Franke Robert
• Priske Markus
• Hess Dieter
• Becker Marc
• Rudek Markus

Classifications

• C07C45/82

  by distillation · CPC title

• C07C45/786 Primary

  by membrane separation process, e.g. pervaporation, perstraction, reverse osmosis · CPC title

• C07C45/50

  by oxo-reactions · CPC title

• C07C29/16

  by oxo-reaction combined with reduction · CPC title

• B01J2231/321

  Hydroformylation, metalformylation, carbonylation or hydroaminomethylation · CPC title