E.i. Dupont De Nemours and Company

Conoco Inc.

Paul C Yates

Madhusudan D Jayawant

James Lee Hecht

Richard A Harmon

Karl E Bennett

John L Fitzjohn

A process for selectively plugging permeable zones in subterranean formations or for plugging subterranean leaks which comprises injecting into the permeable zone or the site of the subterranean leak an aqueous solution containing 1 to 70 weight percent of a non-aggregated colloidal silica sol having a particle size in the range between 4 and 100 nm and a pH in the range between about 1 and 10, and causing said solution to gel in said zone or at said site.

Colloidal silica-based fluid diversion

Use of a selected antimonate has been found to increase flame-retardancy without lowering thermal resistivity of a polyurethane terephthalate molding blend which contains an ionic hydrocarbon copolymer or ionic salt of a hydrocarbon acid and a low molecular weight compound.

Polyethylene terephthalate blends

The catalytic vapor phase oxidation of an olefin of 3 to 5 carbon atoms to .alpha.,.beta.-unsaturated aldehydes with the formation of substantially no .alpha.,.beta.-unsaturated acids is achieved by contacting the olefin, oxygen, an inert gas or moderator and optionally water with a catalyst at a temperature of from 300.degree. C. to 500.degree. C. for a period of time sufficient to achieve from 25 to 80% conversion of said olefin to said aldehyde, separating unreacted olefin and byproduct inert gas from the product stream and recycling the unreacted olefin and byproduct inert gas together with additional olefin and oxygen if required to react with said catalyst.

High yield, low byproduct .alpha., .beta.-unsaturated aldehydes from

The fluoride values of fluorapatite ores can be recovered by using reactive metal compounds, e.g., the sulfates, phosphates or hydroxides of aluminum, iron, titanium, zirconium, antimony or chromium, to tie up the fluorides during acid attack on the ores and thus minimize the formation of fluosilicic acid. The soluble metal fluoride salts formed can subsequently be separated and treated with acid to recover hydrogen fluoride.

Recovery of fluoride values

Spheroidal aggregates of highly absorbent, low bulk density, readily soluble, high surface area, hydrated, amorphous alkali metal silicate are provided by contacting discrete alkali metal silicate particles with an aqueous solution of hydrogen peroxide, absorbing the peroxide into the alkali metal silicate hydrated structure and heating the silicate to destroy substantially all of the hydrogen peroxide. CROSS REFERENCE TO RELATED APPLICATION

Highly absorbent, low bulk density sodium silicate

Sodium percarbonate of improved storage stability in solid bleach and detergent formulations is made by contacting the sodium percarbonate particles with an aqueous sol containing 3 to 8 percent W/V (gm./100 cc.) of silica which has a maximum particle size of 0.1 micron and which is prepared by deionizing a solution of a water soluble silicate to a pH of 3 to 10, in order to deposit on the percarbonate particles from 1 to 10 percent by weight of silica based on the weight of the percarbonate.

Silica sol stabilizers for improving the stability of sodium

Spheroidal aggregates of highly absorbent, low bulk density, readily soluble, high surface area, hydrated, amorphous alkali metal silicate are provided by contacting discrete alkali metal silicate particles with an aqueous solution of hydrogen peroxide, absorbing the peroxide into the alkali metal silicate hydrated structure and heating the silicate to destroy substantially all of the hydrogen peroxide.

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Wilmington, DE, United States of America

Paul C Yates