CA2337817A1 - Compositions of tetrakis (hydroxymethyl) phosphonium salts with an antifoaming agent - Google Patents

Abstract

Foaming of synergistic biocidal mixtures of tetrakis(hydroxymethyl)phosphonium salts and surfactants is controlled by a C10-20 acetylenic diol.

Description

_ ~ V'O 99/46989 PCT/EP99/01813 COMPOSITIONS OF TFTRAKIS (HYDROXYMETHYL) PHOSPHONIUM SALTS WIT~i AN
ANTffOAMING AGENT
The present invention relates to synergistic biocidal mixtures containing hydroxymethyl phosphonium biocides with surfactants and foam inhibitors.
GB 2 145 708 describes biocidal uses of tetrakis (hydroxymethyl) phosphonium salts, which, together with their parent base tris(hydroxymethyl)phosphine, are referred to herein collectively as "THP". GB 2 178 960 describes synergism between THP salts and surfactant. GB 2 228 680 describes synergism between THP salts and certain aldehydes.
THP formulations are increasingly widely used as biocides for water treatment in treating cooling water, process water e.g. in pulp and paper manufacture, drilling fluids and other aerobic water systems, as well as in anaerobic systems such as oil field formation water, injection water, produced water and water used in hydrostatic testing. Advantages include rapid and effective bactericidal activity and environmental acceptability. Particularly in systems where slime forming bacteria proliferate (e.g. in aerobic systems such as cooling water) it has been found desirable to use THP formulations containing synergistic amounts of a biopenetrant which is usually a surfactant according to GB 2 178 960, in order to improve cost effective biocidal action. However such formulations cause foaming problems. Attempts to control foaming by use of antifoams have proved unsatisfactory because the commonly used antifoams have proved incompatible with, unstable in the presence of, or ineffective in relation to, THP
surfactant systems. More than 100 different antifoams have been screened and found ineffective. Many separate from the system on standing.
As a result efforts have been made to develop non-surfactant biopenetrants.
However, for some applications, surfactants would be preferred if the foaming could be controlled We have now discovered that C,o_zo acetylenic diols provide effective foam inhibitors which are compatible with THPlsurfactant systems.
Our invention therefore provides a low foaming biocidal composition comprising THP, a synergistic amount of a surfactant and sufficient of a C,~.2z acetylenic diol to inhibit foaming of the composition.
According to a second embodiment the invention provides a method of treating aqueous systems contaminated, or liable to contamination, with bacteria, fungi or algae which comprises applying thereto separately or together a biocidally active amount of the components of~a synergistic mixture as aforesaid.
The aqueous system may, for instance, be contaminated with bacterial slime.
The invention is of use for treating aerobic systems and also for anaerobic systems.
The acetylenic diof is preferably a branched chain acetylenic diol and especially a diol with two secondary or preferably tertiary alcohol groups, e.g. a compound of the formula R' R' R- C- R"- C- R
OH OH
wherein each of the R groups, which may be the same or different, is a straight or preferably branched chain alkyl group having .from 1 to 8, (preferably 3 to 7) carbon atoms and each R', which may be the same or different is hydrogen or a C~ ro s alkyl group, preferably a methyl group and R" is a CZ to 8 acetylenic group, preferably C2. The diof preferably has a total of from 12 to 20, more preferably 14 to 18, e.g. 15 to 17 carbon atoms. Especially preferred are compounds such as 2, 5, 8, 11-tetramethyldodec-fi-yne-5,8-diol.

- WO 99146989 3 PCTlEP99/01813 The THP is preferably a THP salt such as the sulphate, chloride or phosphate.
However any water soluble salt may be used including the nitrate, phosphite, bromide. fluoride. carbonate, acetate. formate, citrate, borate. or silicate.
In fact any counter ion which is chemically compatible with the THP cation may be used.
The main criteria for selection are usually economic.
The surfactant may be an anionic, non-ionic. cationic or amphoteric surfactant.
Particularly preferred are cationic surfactants such as quaternary ammonium salts, e.g. salts of the formula RR'R"R"'N wherein R is C6 to zo alkyl R' R"
and R"' are each independently selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, hydroxyethyl. and benzyl or in which two of R', R" and R"' form part of an aiicyclic ring. Suitable cationic surfactants include C~0_~4 alkyl dimethylbenzyi ammonium salts and C~a-~A alkyl trimethyi ammonium salts. Other examples of cationic surfactants which may be used include amidoalkyl ammonium, imidazolinium and C~0 to 20 alkyl pyridinium, quinolinium and isoquinoiinium salts. The counter ion of the cationic surfactant is not generally , significant other than on grounds of cost. It is typically chloride but could for instance be sulphate, bisulphate, methosulphate, bromide, formate, acetate, citrate, lactate. tartrate, nitrate or any other chemically compatible and commercially or industrially convenient anion. The counter ion of the cationic surfactant is preferably not itself a surface active ion.
The surfactant may also be or comprise one or more anionic surfactants, especially alkyl benzene sulphonates, alkyl sulphate, alkyl polyethoxy sulphates, olefin suiphonates, paraffin sulphonates, alkyl ester sulphonates, alkyl phenol sulphates, alkyl phenol polyethoxy sulphates and sulphonated mono or di alkylated diphenyi oxides. Other ionic surfactants useful according to the present invention include alkyl sulphosuccinates, such as sodium di-2-ethylhexylsulphosuccinate and sodium dihexylsulphosuccinate, alkyl ether sulphosuccinates. alkyl sulphosuccinamates. alkyl ether sulphosuccinamates, acyl sarcosinates. acyl taurides, isethionates. soaps such as stearates, paimitates, resinates, oleates, linoleates, and alkyl ether carboxyiates. Anionic phosphate VI'O 99/46989 PCTIEP99/01813 esters and alkyl phosphonates. alkyl amino and imino methylene phosphonates may also be used. In each case the anionic surfactant typically contains at least one aliphatic hydrocarbon chain having from 8 to 22, preferably 10 to 20 carbon atoms, and, in the case of ethers, one or more glyceryl andlor from 1 to 20 oxyethylene andlor oxypropylene andlor oxybutyiene groups. The counter ion of the anionic surfactant is usually sodium but can be any other alkali metal, e.g.
potassium or ammonium or a substituted ammonium such as trimethylammonium, monoethanolammonium, diethanolammonium, triethanoiammonium, isopropylammonium or butylammonium. The counter ion of the anionic surfactant is preferably not itself a surfactant ion.
The surfactant may optionally contain or consist of nonionic surfactants. The nonionic surfactant may be, e.g. a C,o-22 alkanolamide of a mono or di- lower alkanolamine, such as coconut monoethanoiamide. Other nonionic surfactants which may optionally be present, include tertiary acetylenic glycols, poiyethoxylated alcohols, polyethoxylated mercaptans, poiyethoxyiated carboxylic acids, polyethoxylated amines, polyethoxylated alkyloamides, poiyethoxylated alkylphenols, polyethoxylated glyceryl esters, polyethoxylated sorbitan esters, polyethoxyiated phosphate esters, and the propoxylates or ethoxylated and propoxylated analogues of all the aforesaid ethoxylated nonionics, all having a C&22 alkyl or alkenyl group and up to 20 ethylenoxy andlor propyienoxy groups.
Also included are polyoxypropylenelpolyethylene oxide copolymers, poljioxybutylene/polyoxyethylene copolymers and polyoxybutylene/poiyoxypropylene copolymers. The polyethoxy, polyoxypropylene and polyoxybutylene compounds may optionally be end-capped with, e.g. benzyi groups to reduce their roaming tendency.
Compositions of our invention may contain amphoteric surfactant.

- V'O 99/46989 5 PCTBP99I01813 The amphoteric surfactant may for example be a betaine, e.g. a betaine of the formula:- R3N+CH2C00', wherein each R is an alkyl, cycloalkyl, alkenyl or alkaryl group and preferably at least one, and most preferably not more than one R, has an average of from 8 to 20, e.g. 10 to 18 aliphatic carbon atoms and each other R
has an average of from 1 to 4 carbon atoms. Particularly preferred are the quaternary imidazoiine betaines of the formula:-N +N CHZCOO-~~~
R' R
wherein R and R' are alkyl, alkenyl, cycloalkyl, alkaryl or alkanoi groups having an average of from 1 to 20 aliphatic carbon atoms and R preferably has an average of from 8 to 20, e.g. 10 to 18 aliphatic carbon atoms and R' preferably has 1 to 4 carbon atoms. Other amphoteric surfactants for use according to our invention include alkyl amine ether sulphates, sulphobetaines and other quaternary amine or quaternised imidazoline sulphonic acids and their salts, an other quaternary amine or quaternised imidazoline carboxylic acids and their salts and Zwitterionic surfactants, e.g. N-alkyl taurines, carboxylates amido amines such as RCONH(CH2)zN+ (CHZCH2GH3)zCH2C02, and amino acids having, in each case, hydrocarbon groups capable of conferring surfactant properties (e.g. alkyl, cycioalkyl, alkenyl or alkaryl groups having from 8 to 20 aliphatic carbon atoms).
Typical examples include 2 tallow alkyl, 1-tallow amido alkyl, 1 carboxymethyl imidazoline and 2 coconut alkyl N-carboxymethyl 2 (hydroxyalkyl) imidazoline.
Generally speaking any water soluble amphoteric or Zwitterionic surfactant compound which comprises a hydrophobic portion including a C8_2o alkyl or alkenyl group and a hydrophilic portion containing an amine or quaternary ammonium group and a carboxylate, sulphate or sulphonic acid group may be used in our invention.

_ WO 99/46989 6 PCT/EP99/01813 Polyfluorinated anionic, nonionic or cationic surfactants may also be useful in the compositions of our invention. Examples of such surfactants are polytluorinated alkyl sulphates and polyfluorinated quaternary ammonium compounds.
Compositions of our invention may contain an amine oxide, e.g. an amine oxide containing one or two (preferably one) C8_ZZ alkyl group, the remaining substituent or substituents being preferably tower alkyl groups, e.g. C» alkyl groups or benzyl groups.
In addition to the THP salt, the surfactant and the acetylenic diol, the biocides of our invention may comprise a water miscible solvent for the acetylenic diol which acts as a vehicle for the latter, enabling it to be introduced into the system and which, additionally may contribute to biopenetration thereby enhancing the biocidal effectiveness of the mixture without causing foaming. Suitable solvents include polyglycols, alkylglycols and polyglycol ethers such as dipropylene glycol, triethylene glycol and diethylene glycol monomethyl or monoethyl ethers.
Preferably the THP and the surfactant are present in a relative weight concentration of from 1:50 to 1000:1, more usually 1:50 to 200:1, typically 1:20 to 100:1, most preferably 1:10 to 50:1, e.g. 1:1 to 20:1, especially 2:1 to 15:1.
The proportion of acetylenic diol is sufficient to inhibit foaming during the blending of the biocide and/or in water systems to which it has been added. Typically the diol is present in a proportion of from 0.01 to 10% by weight based on the weight of THP, more usually 0.05 to 5%, e.g. 0.1 to 2%, especially 0.5 to 1.5%.
The proportion of any solvent is preferably sufficient to dissolve the diol.
Depending on the solubility of the diol in the solvent, and of the solvent in water, the proportion by weight of diol to solvent may typically be from 2:1 to 1:50, more usually 1:1 to 1:20, especially 1:1.5 to 1:10, e.g. 1:2 to 1:3.

WO 99/46989 ~ PCT/EP99/01813 The total concentration of THP in the aqueous biacide may be from 1 % to saturation (usually around 75% by weight), especially 10 to 60%. The invention is of particular value in relation to compositions containing less than 50% by weight THP, which have been found to give rise to particularly intractable foaming problems. The biocide may typically be dosed at a THP level of from 1 to 1500ppm, usually 2 to 500ppm, e.g. 5 to 250ppm, preferably 10 to 150ppm.
Compositions of the invention are also useful in a number of non-biocidal applications such as: leather treatment including pretanning operations such as degreasing, main tanning, retanning and in curing casein and synthetic finishes on leather; hardening photographic emulsions; and dissolving or inhibiting the deposition of iron sulphide in drilling or other operations.

A composition comprising 50% THPS, 5% sodium salt of a suiphonated mono/di afkyiated Biphenyl oxide and 0.5% of a 30% solution of 2, 5, 8, 11-tetramethyldodeca-6-yne-5,8-diol in dipropylene glycol, sold under the Registered Trade Mark "SURFYNOL" DF110D, was found to provide effective biocidal control of sessile and planktonic, aerobic and anaerobic bacteria, fungi and algae when dosed at 500pm. Foaming, compared with a control containing no antifoam, was inhibited by 67%. The composition was stable to storage after twelve months. A
cntltrol composition containing a silicone antifoam had undergone separation after standing for 48 hours.

The compositions listed in table 1 were prepared and tested for foaming by shaking a 20cm3 sample in a 50cm3 measuring cylinder. Foam height was measured immediately after shaking, and after 10 seconds, at concentrations of the sample 100ppm and 1000ppm and the results are listed in table 2.

SAMPLE ~ COMPARATIVE (A) COMPARATIVE (B) E~MPLE
(No Antifoam) (Silicone 2 Lauryl Sodium Sulphate0.56 0.56 0.56 "SURFYNOL" DF110D -- --- 0.35 Silicone -- 0.35 ---TABLE 2 .
SAMPLE 100ppm initial100ppm 10 sets1000ppm initial1000oom 10 sets ( Example 5 0 11 5 Examples 3 to 8 Example 2 was repeated using the following surfactants in place of sodium lauryl sulphate. In each case satisfactory foam characteristics were observed:-3. C,2_,4 alkyl betaine.

4. Disodium dialkyl sulphosuccinamate.

5. C,2.,4 alkyl 3-mole ethoxy sulphate.

6. C,2 alkyl tris(hydroxymethyl)phosphonium chloride.

7. C,2.,a alkyl benzyl dimethyl ammonium chloride.

8. Coconut amido propyl dimethyl betaine.

Claims (8)

9

1. A biocidal composition comprising an aqueous solution of THP, a biocidally synergistic amount of a surfactant and sufficient C10-20 acetylenic diol to inhibit foaming of the composition.

2. A composition according to claim 1 where said diol comprises two tertiary alcohol groups.

3. A composition according to claim 2 wherein said diol is 2,5,8,11-tetramethyldodec-6-yne-t,8,-diol.

4. A composition according to claim 1 comprising from 1 to 80% by weight THP.

5. A composition according to claim 4 comprising from 10 to 60% THP.

6. A composition according to any foregoing claim containing THP and surfactant in a weight ratio of 1:50 to 1000:1.

7. A composition according to any of claims 1 to 6 containing a water miscible solvent for the acetylenic diol in an amount sufficient to dissolve the diol component of the composition.

8. A method of treating aqueous systems contaminated, or liable to contamination, with bacteria, fungi or algae which comprises applying thereto separately or together a biocidally active amount of the components of a composition according to claim 1.