Embedded Biocide

Abstract

A phosphonium compound embedded in a matrix substrate wherein the phosphonium compound is selected from a group consisting of tris (hydroxyorgano) phosphine (THP), a THP+ salt (tetrakis (hydroxyorgano) phosphonium salt) or a condensate of THP and a nitrogen containing compound. The compound may be used to reduce the numbers of micro organisms in industrial systems and may also be used to reduce iron carbonate or iron, lead and zinc scale deposits.

Description

EXAMPLE 1

A polyethylene glycol with a weight average molecular weight of 8000 (PEG8000) is used to produce matrix substrate containing THPS, that has a melting point of approximately 50° C. (suitable for storage in most areas of the world) and readily dissolving within 5 minutes in water at 20° C.

EXAMPLE 2

As shown in Table 1 below, THPS, embedded within a PEG8000 matrix, can be deployed in the presence of an oxygen scavenger without hindering the deaeration process. Experiment three shows complete deaeration within 15 seconds when an embedded biocide in accordance with the present invention is used, compared with no deaeration when a liquid biocide is used (Experiment 2).

EXAMPLE 3

The THPS/PEG8000 candle described above was tested in a standard quantitative suspension test to measure the antimicrobial activity of the embedded biocide. Such tests involve the addition of the biocide to the system water for a specified contact period, deactivation of the biocide after the specified contact period and subsequent enumeration of the remaining viable bacteria using Most Probable Number (MPN) techniques widely known within the industry.

From the graph below (Graph 1) it can be seen that THPS embedded in a PEG8000 matrix substrate (Tolcide® candle H2) has no adverse effects upon the antimicrobial performance of THPS when compared with liquid THPS (Tolcide® PS75).

The control shows the viability of the bacteria when not exposed to THPS.

TABLE 1
		Oxygen	Time to
		Scavenging	reach
EXP	Description	Y/N	zero O2	Comments
1	500 ppm erythorbic	Y	15 seconds	This confirms
	acid (oxygen			the deaeration
	scavenger) in water:			efficacy of
	using15 ppm			erythrobic
	catalyst-CuSO4			acid-
2	Repeat of	N	Virtually no
	experiment 1 but		deaeration
	450 ppm THPS was		occurred
	introduced via a		even after
	conventional		15 minutes)
	liquid product
3	Repeat of	Y	15 seconds	Solid
	experiment 1 but			dissolved
	450 ppm THPS,			in ~5 min
	encapsulated
	within a PEG8000
	candle, was
	introduced.

Claims

1-28. (canceled)

29. A phosphonium compound embedded in a matrix substrate wherein the phosphonium compound is selected from a group consisting of tris (hydroxyorgano) phosphine (THP), a THP+ salt (tetrakis (hydroxyorgano) phosphonium salt) or a condensate of THP and a nitrogen containing compound, and wherein the matrix substrate has a melting point of between 5 to 80° C. and is soluble in water at a temperature of between 5 to 100° C. optionally of 20° C.

30. The phosphonium compound as claimed in claim 29, wherein the THP+ salt is tetrakis (hydroxymethyl) phosphonium sulphate.

31. The phosphonium compound as claimed in claim 29, wherein the THP salt is selected from the group consisting of tetrakis (hydroxymethyl) phosphonium chloride, tetrakis (hydroxymethyl) phosphonium phosphate, tetrakis (hydroxymethyl) phosphonium formate, tetrakis (hydroxymethyl) phosphonium acetate and tetrakis (hydroxymethyl) phosphonium oxalate.

32. The phosphonium compound as claimed in claim 29, wherein the nitrogen containing compound is urea.

33. The phosphonium compound as claimed in claim 29, wherein the nitrogen containing compound is melamine, guanidine or dicyandiamide.

34. The phosphonium compound as claimed in claim 29, wherein the matrix substrate has a melting point of between 20 to 70° C., optionally of 60° C.

35. The phosphonium compound as claimed in claim 34, wherein the matrix substrate is a polyhydric compound.

36. The phosphonium compound as claimed in claim 35, wherein the polyhydric compound is a polyethylene glycol with a molecular weight of above 600.

37. The phosphonium compound as claimed in claim 35, wherein the polyhydric compound is polyethylene glycol 8000.

38. The phosphonium compound as claimed in claim 29, wherein the matrix substrate is selected from the group consisting of ethoxylated surfactants, fatty alcohols, ethoxylated fatty alcohols, ethoxylated alkyl phenols, ethoxylated fatty acids, fatty acid alkanolamides, ethylene oxide/propylene oxide block copolymers, ethoxylated/propoxylated fatty alcohols, polyethylene glycol esters, glycol esters, alkyl benzene sulphonic acids and salts thereof.

39. The phosphonium compound as claimed in claim 29, wherein the matrix substrate is a mixture of two or more of the polyhydric compound as defined in claim 29.

40. A method for reducing the numbers of micro-organisms in an industrial system which method comprises the step of contacting the industrial system with an effective amount of phosphonium compound as defined in claim 29 to reduce the number of micro-organisms.

41. A method for reducing the amount of scale in an industrial system which method comprises the step of contacting the industrial system with an effective amount of a phosphonium compound as defined in claim 29 to reduce the amount of scale.

42. A formulation comprising a phosphonium compound as defined in claim 29 and one or more of the following: scale inhibitors, corrosion inhibitors, additional biocides, demulsifiers, gas hydrate inhibitors, asphaltene inhibitors/dispersants, other surfactants, anti-foams/defoamers, fragrances, wax inhibitors, scale dissolvers, gelling agents, oxygen scavengers.

43. Sticks/candles, beads, pellets, bricks, shavings, flakes or prills comprising a phosphonium compound as defined in claim 29.