E.i. Dupont De Nemours and Company

Chester A Thayer, Ii

Allan Cairncross

Harold E Bellis

Edward F Moran, Jr

A process for making an alkanedioic acid in which a mixture of a cycloalkene, a base and a solvent is contacted simultaneously with both oxygen and ozone at a temperature between 40 and 60 degrees Centigrade.

One step process for producing dicarboxylic acids

Continuous processes for converting cycloalkenes into ozonides in which ozone is reacted with a cycloalkene to form an ozonide solution. A portion of the solution is recycled back to the reaction, and additional cycloalkene is provided.

Continuous ozonolysis of cycloalkenes into ozonides

Polymeric ledges on a metal stencil screen are made using a polymeric layer which is partially removed by a developer solution.

Process for making improved metal stencil screens for screen printing

A process for preparing lactide or glycolide from a lactic acid oligomer or glycolic acid oligomer is disclosed where the molecular weight of the synthesis reactor residue is controlled to no more than 1.2 times that in the feed. The process is carried out at 130.degree. to 280.degree. C. and preferably 180.degree. to 210.degree. C. using from 1 to 6 weight percent catalyst in the oligomer feed to the synthesis reactor. The catalysts are tin or tin compounds, yttrium or rare earth metal compounds, or antimony compounds which are known as alphahydroxycarboxylic acid cyclic dimerization or polymerization catalysts.

Process for the synthesis of lactide or glycolide from lactic acid or

A process for making a metal ledge on one side of a metal screen involves exposing through the stencil screen a photoresist layer, removing unexposed photoresist areas, plating the metal stencil screen where the unexposed photoresist has been removed and removing the exposed photoresist.

Process for making metal ledge on stencil screen

A process is described for defined etching of holes using a sliver mask formed by silver diffusion transfer imaging.

Growing community of inventors

Wilmington, DE, United States of America

Chester A Thayer, Ii