Fmc Corporation

Fmc Corporation (uk) Limited

Ciba-geigy Corporation

Jan Rideout

Brian G Clubley

Elizabeth A Kerr

Duncan J MacQuarrie

Phosphonic coletomers of the formula I: ##STR1## wherein X.sub.5 is hydrogen, an alkali metal atom, an alkaline earth metal atom, or an ammonium or amine residue; and A.sub.2 is a copolymer residue comprising two different residues ##STR2## wherein r is an integer ranging from 2 to 100, and wherein, in the first residue, W.sub.3 is --COOH, and in the second residue, W.sub.3 is --CONHC(CH.sub.3).sub.2 CH.sub.2 SO.sub.3 X.sub.5 wherein X.sub.5 is as hereinbefore defined. The cotelomers inhibit scale and corrosion in aqueous systems.

Phosphonic cotelomers and method of use

Phosphonic telomer intermediates for preparing the telomers of U.S. Pat. No. 5,376,731 may be produced by an aqueous process comprising (a) reacting hypophosphorous acid with a carbonyl compound which is preferably an aldehyde, a ketone or an imine, and (b) reacting the product of (a) with an olefinic reactant or reactants in the presence of a suitable initiator especially a free radical initiator. The telomer intermediates are themselves useful as scale inhibitors in aqueous systems.

Telomers

Phosphonic (co) telomers of the type described in U.S. Pat. Nos. 4,046,707 and 4,681,686 and European Patent Application 360746 may be produced by an aqueous process comprising (a) reacting hypophosphorous acid with a carbonyl compound which is preferably an aldehyde, a ketone or an imine, (b) reacting the product of (a) with an olefin or olefins in the presence of a suitable initiator especially a free radical initiator, and (c) converting the product obtained from (b) to a phosphonic (co) telomer, e.g., by reaction with hypochlorite. The (co) telomer products are useful as scale inhibitors in aqueous systems.

A method of inhibiting the precipitation of barium scale from an aqueous system, comprising adding to the aqueous system a product having the formula I: ##STR1## in which M is hydrogen or an alkali metal ion, an ammonium ion or a quanternized amine radical; R.sub.1 is hydrogen or methyl; and n is an integer having an average value ranging from 4 to 20.

Inhibition of scale

A corrosion- and/or scale inhibitor composition comprising: A) a corrosion- and/or scale inhibitor; and B) a compound having the formula (I): ##STR1## or a water-soluble salt thereof in which R.sub.1 is hydrogen or methyl, the weight ratio of component A) to component B), ranging from 10:90 to 90:10. The compounds of formula I are new compounds.

Corrosion and/or scale inhibition

A method of inhibiting corrosion of metal surfaces in contact with an aqueous system, comprising contacting the metal surfaces with a telomer compound having the formula I: ##STR1## in which M is hydrogen or an alkali or alkaline earth metal ion, an ammonium ion or a quaternised amine radical; and n is an average integer ranging from 1 to 60.

Corrosion inhibition

A method of inhibiting the precipitation of calcium carbonate scale from an aqueous system, comprising adding to the aqueous system, a compound having the formula I: ##STR1## in which M is hydrogen or an alkali metal ion, an ammonium ion or a quaternized amine radical; R.sub.1 is hydrogen or methyl; and n is an integer ranging from 1 to 10.

Scale inhibition

Polymaleic anhydride having a weight average molecular weight by gel permeation chromatography of between 450 and 800 and a polydispersivity of between 1.0 and 1.15 is produced by polymerizing maleic anhydride, using a peroxide initiator in an amount not greater than 10% by weight of the anhydride, in a dilute solution in o-xylene or a substituted o-xylene.

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Bolton, United Kingdom

Jan Rideout