Patents by Inventor Dennis A. Ruest

Dennis A. Ruest has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6548701
    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.
    Type: Grant
    Filed: October 5, 2001
    Date of Patent: April 15, 2003
    Assignee: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Publication number: 20020173677
    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.
    Type: Application
    Filed: October 5, 2001
    Publication date: November 21, 2002
    Applicant: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Patent number: 6320076
    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.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: November 20, 2001
    Assignee: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Patent number: 6031138
    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.
    Type: Grant
    Filed: June 22, 1998
    Date of Patent: February 29, 2000
    Assignee: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Patent number: 5925794
    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.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: July 20, 1999
    Assignee: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Patent number: 5744647
    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.
    Type: Grant
    Filed: July 11, 1996
    Date of Patent: April 28, 1998
    Assignee: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Patent number: 5637766
    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.
    Type: Grant
    Filed: November 13, 1995
    Date of Patent: June 10, 1997
    Assignee: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Patent number: 5352837
    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.
    Type: Grant
    Filed: June 8, 1993
    Date of Patent: October 4, 1994
    Assignee: Novus International, Inc.
    Inventors: Yung C. Hsu, Dennis A. Ruest
  • Patent number: 4883911
    Abstract: A process for the preparation of alkylthioalkanoate salts by reaction of an alkali metal alkylmercaptide with a lactone in the presence of an aprotic polar organic solvent. Preferably, the alkali metal mercaptide is prepared by reaction of an alkylmercaptan and an alkali metal phenate.
    Type: Grant
    Filed: October 6, 1988
    Date of Patent: November 28, 1989
    Assignee: Monsanto Company
    Inventor: Dennis A. Ruest
  • Patent number: 4777289
    Abstract: A process for the preparation of alkylthioalkanoate salts by reaction of an alkali metal alkylmercaptide with a lactone in the presence of an aprotic polar organic solvent. Preferably, the alkali metal mercaptide is prepared by reaction of an alkylmercaptan and an alkali metal phenate.
    Type: Grant
    Filed: May 8, 1986
    Date of Patent: October 11, 1988
    Assignee: Monsanto Company
    Inventor: Dennis A. Ruest
  • Patent number: 4524077
    Abstract: A process for the preparation of 2-hydroxy-4-methylthiobutyric acid having improved color, odor and lower viscosity. 2-hydroxy-4-methylthiobutyric acid which is also known as 2-hydroxy-4-(methylthio) butanoic acid, is hydrolyzed with sulfuric acid having an initial strength of between about 50% by weight and about 70% by weight on an organic-free basis, thereby producing an intermediate aqueous hydrolysis product solution containing 2-hydroxy-4-methylthiobutyramide. The 2-hydroxy-4-methylthiobutyramide is hydrolyzed with sulfuric acid having a strength of between about 30% by weight and about 50% by weight on an organic-free basis to produce an aqueous hydrolyzate containing 2-hydroxy-4-methylthiobutyric acid. The hydrolyzate solution is contacted with a substantially water-immiscible organic solvent in a liquid-liquid extraction system to produce an extract comprising the solvent and 2-hydroxy-4-methylthiobutyric acid transferred from the hydrolyzate. The acid product is then recovered from the extract.
    Type: Grant
    Filed: November 14, 1983
    Date of Patent: June 18, 1985
    Assignee: Monsanto Company
    Inventors: Dennis A. Ruest, Masaharu Takano, Lawrence R. Wolf
  • Patent number: 4080376
    Abstract: Novel imide carboxylates, O-carboxylates thereof, and amide carboxylates are useful as intermediates for preparation of sequestrant compounds.
    Type: Grant
    Filed: April 19, 1976
    Date of Patent: March 21, 1978
    Assignee: Monsanto Company
    Inventors: Chung Y. Shen, Roger L. Kidwell, Dennis A. Ruest
  • Patent number: 4059579
    Abstract: Novel imide carboxylates, O-carboxylates thereof, and amide carboxylates are useful as intermediates for preparation of sequestrant compounds.
    Type: Grant
    Filed: October 10, 1974
    Date of Patent: November 22, 1977
    Assignee: Monsanto Company
    Inventors: Dennis A. Ruest, Roger L. Kidwell, Chung Y. Shen
  • Patent number: 3935257
    Abstract: Compounds represented by the formula ##EQU1## wherein M is alkali metal and acids thereof are useful intermediates for preparation of sequestrant compounds represented by the formula ##EQU2## and acids thereof.
    Type: Grant
    Filed: March 18, 1974
    Date of Patent: January 27, 1976
    Assignee: Monsanto Company
    Inventors: Dennis A. Ruest, C. Y. Shen, John L. Mason