Patents by Inventor Yog R. Dhingra

Yog R. Dhingra 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: 5302623
    Abstract: Cation-exchange resins are provided which have improved resistance to copolymer degradation caused by oxidizing agents like molecular oxygen. The resins are prepared by incorporating a para-substituted styrenic monomer having an oxidation-stabilizing moiety in a position para to a polymerizable vinyl moiety. These cation-exchange resins can be used in separation processes for longer periods of time without detrimental increases in bed pressure drops, loss of operating capacity, or leaching of organic contaminants.
    Type: Grant
    Filed: March 2, 1993
    Date of Patent: April 12, 1994
    Assignee: The Dow Chemical Company
    Inventors: Yog R. Dhingra, Paul R. VanTol
  • Patent number: 5221478
    Abstract: This invention is a process for the chromatographic separation of a fluid mixture in which the mixture is contacted with an ion-exchange resin, eluted through the resin under conditions such that the rate of passage of one component of the mixture through the resin bed is retarded relative to the rate of passage of a second component of the mixture, and a first product stream rich in said first component and a second product stream rich in said second component are recovered. The invention involves the use of an ion-exchange resin made from a copolymer which is prepared in a multi-stage polymerization process. The use of this resin is found to provide fast separation kinetics and increases the overall speed and efficiency of the separation. This invention is particularly suited for fructose/glucose separations in the preparation of high fructose corn syrup.
    Type: Grant
    Filed: September 9, 1992
    Date of Patent: June 22, 1993
    Assignee: The Dow Chemical Company
    Inventors: Yog R. Dhingra, Bruce W. Pynnonen
  • Patent number: 5176832
    Abstract: The present invention is a process for the chromatographic separation of a liquid mixture comprising a first sugar component and at least one secondary component chosen from second sugars, organic acids and salts thereof, alcohols, amino acids, and inorganic salts. In the process, the liquid mixture is contacted with a stratum of a porous gel cation-exchange resin and thereafter eluted such that the first sugar component passes through the stratum at a different rate relative to the secondary components of the liquid mixture. The separation results in a first recoverable product stream rich in the first sugar component and at least one secondary product stream rich in the secondary components. The porous gel cation-exchange resin is prepared by polymerization of at least one monovinylidene monomer with a cross-linking monomer in the presence of an inert diluent.
    Type: Grant
    Filed: October 23, 1991
    Date of Patent: January 5, 1993
    Assignee: The Dow Chemical Company
    Inventors: Antonio Dorta, Yog R. Dhingra, Bruce W. Pynnonen
  • Patent number: 4117007
    Abstract: Bis-chloromethyl ether (CME) and 1,1,1,2-tetrachloroethane (TCE) impurities are efficiently eradicated from chloroacetyl chloride (CAC) by a process comprising contacting the CAC, containing about 100 to about 250 ppm CME and about 1 weight percent, based on the weight of the CAC, of TCE, with a catalytic amount of ferric and/or aluminum cations at a temperature at least about 50.degree. C. This process does not require hydrochloric acid and yields CAC containing less than detectable (<0.5 ppm CME, <0.05 wt. % TCE) amounts of the impurities.
    Type: Grant
    Filed: October 17, 1977
    Date of Patent: September 26, 1978
    Assignee: The Dow Chemical Company
    Inventors: Robert A. Bredeweg, Yog R. Dhingra
  • Patent number: 4087278
    Abstract: Chloral hydrate bis-ester of 2,2,3-trichloropropionic acid, CCl.sub.3 CH(OCOCCl.sub.2 CH.sub.2 Cl).sub.2, its preparation by reacting chloral hydrate with 2,2,3-trichloropropionyl chloride and herbicidal compositions containing chloral hydrate bis-ester of 2,2,3-trichloropropionic acid.
    Type: Grant
    Filed: September 3, 1974
    Date of Patent: May 2, 1978
    Assignee: The Dow Chemical Company
    Inventors: Yog R. Dhingra, Zdravko Jezic
  • Patent number: 4054602
    Abstract: Bis-chloromethyl ether is efficiently removed from chloroacetyl chloride by a process comprising contacting the chloroacetyl chloride containing generally about 100 to about 250 ppm bis-chloromethyl ether with hydrochloric acid at a temperature between about 30.degree. C and about 160.degree. C in the presence of a catalytic amount of a Lewis or strong protic acid, such as aluminum chloride or oleum. After a contact time of about 1 hour, the chloroacetyl chloride contains less than 0.3 ppm bis-chloromethyl ether.
    Type: Grant
    Filed: September 30, 1976
    Date of Patent: October 18, 1977
    Assignee: The Dow Chemical Company
    Inventor: Yog R. Dhingra