US 6,548,701 B2Granted

Process for the preparation of 3-(methylthio)propanal

AssigneeNovus International, Inc.

InventorsYung C. Hsu, Dennis A. Ruest

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Abstract

A process for the continuous preparation of 3-(methylthio)propanal. A liquid reaction medium is contacted with a gaseous acrolein feed stream in a gas/liquid contact zone. The reaction medium contains 3-(methylthio)propanal, methyl mercaptan and a catalyst for the reaction between methyl mercaptan and acrolein. The gaseous acrolein feed stream comprises acrolein vapor and non-condensable gas. Acrolein is transferred from the acrolein feed stream to the reaction medium and reacts with methyl mercaptan in that medium to produce a liquid reaction product containing 3-(methylthio)propanal. The non-condensable gas is separated from the liquid reaction product. The reaction product is divided into a product fraction and a circulating fraction, and the circulating fraction is recycled to the gas/liquid contact zone.

Claims25

Dependent claims

A process for the preparation of 2-hydroxy-4-(methylthio) butanoic acid comprising:

continuously contacting a liquid reaction medium with an acrolein feed stream, said reaction medium containing 3-(methylthio)propanal and a catalyst for the reaction between methyl mercaptan and acrolein;
continuously introducing methyl mercaptan into said liquid reaction medium;
reacting acrolein and methyl mercaptan in said reaction medium in a continuous reaction zone, thereby producing 3-(methylthio) propanal;
continuously withdrawing a 3-(methylthio)propanal reaction product from said continuous reaction zone;
contacting 3-(methylthio)propanal produced in said continuous reaction zone with hydrogen cyanide to produce 2-hydroxy-4-(methylthio) butanenitrile;
contacting said 2-hydroxy-4-(methylthio)butanenitrile with sulfuric acid to produce a hydrolyzate comprising 2-hydroxy-4-(methylthio)butanoic acid;
and
contacting said hydrolyzate with a substantially water-immiscible organic solvent to produce an extract comprising said solvent and 2-hydroxy-4-(methylthio)butanoic acid.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/972,748Filed 5 Oct 2001 · continuation
Priority: 8 Jun 1993
Published: US 2002/0173677 A121 Nov 2002
Granted: 15 Apr 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

C07C 45/35
In unsaturated compounds: in propene or isobutene
C07C 45/783
Separation; Purification; Stabilisation; Use of additives: by gas-liquid treatment, e.g. by gas-liquid absorption
C07C 45/81
Separation; Purification; Stabilisation; Use of additives: by change in the physical state, e.g. crystallisation
C07C 319/18
Of sulfides: by addition of thiols to unsaturated compounds

Family

Application08/073,763Parent of this continuation-in-part · filed 8 Jun 1993
Application08/273,216Parent of this continuation · filed 11 Jul 1994
Application60/000,421Us provisional application · filed 22 Jun 1995
Application08/557,699Parent of this continuation-in-part · filed 13 Nov 1995
Application08/667,099Parent of this continuation · filed 20 Jun 1996
Application08/668,572Parent of this continuation · filed 20 Jun 1996
Application09/102,025Parent of this division · filed 22 Jun 1998
Application09/470,407Parent of this continuation · filed 22 Dec 1999
US 2002/0173677 A1Pre-grant publication · published 21 Nov 2002
US 6,320,076 B1Parent of this continuation
Application09/470,407Parent of this division
US 6,031,138 AParent of this division
Application09/102,025Parent of this continuation
US 5,905,171 AParent of this continuation
US 5,925,794 AParent of this continuation
Application08/668,572Parent of this continuation-in-part
US 5,637,766 AParent of this continuation-in-part
Application08/557,699Parent of this continuation
Application08/273,216Parent of this continuation-in-part
US 5,352,837 AParent of this continuation-in-part
US 6,548,701 B2This patent

From the US filing history. Foreign family members aren’t listed.