Patents by Inventor Leonard S. Silbert

Leonard S. Silbert 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: 4262137
    Abstract: Isopropenyl esters and half isopropenyl ester-half carboxylic acid products are prepared by reacting at a temperature of about 150.degree.-160.degree. C. at maximum pressures of from about 400 to 1000 psi for about 10 to 20 hours in the presence of a suitable catalyst and in N-methyl-2-pyrrolidone, a saturated or unsaturated aliphatic or aromatic dicarboxylic acid with methylacetylene or with a gas containing a mixture of methylacetylene, allene and some inert short chain hydrocarbons.
    Type: Grant
    Filed: September 21, 1977
    Date of Patent: April 14, 1981
    Assignee: The United States of America as represented by the Secretary of Agriculture
    Inventors: Leonard S. Silbert, Samuel Serota
  • Patent number: 4152115
    Abstract: Water repellancy is imparted to fibrous cellulosic textile material by applying to it, for a very short period of time, an isopropenyl ester containing a catalytic amount of an acid catalyst and then heat curing the treated material. Excellent water repellancy is obtained at a very low degree of substitution and a high degree of retention of tensile strength.
    Type: Grant
    Filed: February 15, 1978
    Date of Patent: May 1, 1979
    Assignee: The United States of America as represented by the Secretary of Agriculture
    Inventors: Leonard S. Silbert, Samuel Serota, Gerhard Maerker
  • Patent number: 4152198
    Abstract: Paper and paperboard made of felted cellulose fibers are chemically modified by applying to them an isopropenyl ester containing a catalytic amount of an acid catalyst and then heat curing the treated product. The process imparts water repellancy to the paper products with a very low degree of add-on, but with a very high degree of retention of tensile strength. The products also have excellent printability, are resistant to boiling water, and retain their opacity after exposure to water.
    Type: Grant
    Filed: February 15, 1978
    Date of Patent: May 1, 1979
    Assignee: The United States of America as represented by the Secretary of Agriculture
    Inventors: Samuel Serota, Leonard S. Silbert, Gerhard Maeker
  • Patent number: 3963784
    Abstract: Aldehydes are prepared by metalating an aliphatic carboxylic acid with lithium diisopropylamide in a mixed solvent system of tetrahydrofuran-hexane-hexamethylphosphoramide to form a dianion of the acid, reacting the dianion in the mixed solvent system with ethyl formate and decarboxylating the resulting alpha-aldehyde acid salt.
    Type: Grant
    Filed: December 19, 1973
    Date of Patent: June 15, 1976
    Assignee: The United States of America as represented by the Secretary of Agriculture
    Inventors: Philip E. Pfeffer, Leonard S. Silbert