The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 07, 1992
Filed:
Apr. 11, 1990
Wolfgang Glasser, Blacksburg, VA (US);
Kaliprasanna Dhara, West Bengal, IN;
Virginia Tech Intellectual Properties, Inc., Blacksburg, VA (US);
Abstract
Lignin sulfonates are converted into sulfonic acid esters by blocking free phenolic hydroxyl groups on the lignin sulfonates from reaction with a suitable protective group, subjecting the blocked lignin sulfonate in aqueous solution to ion exchange to produce the free sulfonic acid thereof, exchanging the aqueous solvent into a polar organic solvent, such as isopropanol, and reacting the sulfonic acid derivative in the polar organic solvent with a saturated or unsaturated aliphatic epoxide, preferably an alkylene oxide. The resulting sulfonic acid ester adduct may be isolated and purified from the reactants using solvent extraction. Lignin sulfonic acid ester adducts are produced that are soluble in a variety of organic solvents and insoluble in water.