The Dow Chemical Company

Edwin R Henson

Joel G Courtwright

Tipton T Masterson

Peter A Doty

David J Koranek

A high density brine useful as a drilling fluid for deep wells is rendered corrosion resistant by the incorporation of a soluble aliphatic or aromatic aldehyde with or without olefinic unsaturation and with the use of alkali metal thiocyanates or ammonium thiocyanates. The aldehyde can be reacted with a primary amine prior to use.

Corrosion inhibitors for aqueous brines

The corrosion of metals in contact with corrosive fluids is effectively inhibited by the addition of one or more phenyloxazoles, preferably 2,5-diphenyloxazole.

Use of phenyloxazoles as corrosion inhibitors

This invention relates to a corrosion inhibiting composition for ferrous metals and its alloys in gas conditioning service using aqueous monoethanolamine to scrub carbon dioxide containing oxygen. The corrosion inhibiting composition includes a thiourea-amine-formaldehyde based polymer and, in the preferred embodiment, also includes a cupric ion producing material.

Corrosion inhibitors for alkanolamines

This invention relates to a corrosion inhibiting composition for ferrous metals and its alloys in gas conditioning service using aqueous monoethanolamine to scrub carbon dioxide. The corrosion inhibiting composition includes a thiourea-amine-formaldehyde based polymer and, in the preferred embodiment, also includes a nickel ion producing material.

In a new method of producing 4-amino-3,5,6-trichloropicolinic acid 3,4,5,6-tetrachloropicolinonitrile is reacted with ammonium hydroxide, preferably at about 130.degree. C. to about 160.degree. C. The free acid is precipitated upon acidification of the reaction mixture and may be recovered therefrom.

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Lake Jackson, TX, United States of America

Edwin R Henson