CA1269300A - Synergistic biocide of tributyl tetradecyl phosphonium chloride and 1,5-pentanedial - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A superior industrial biocide for treating industrial process waters is afforded in the combination of 1,5-pentanedial and tributyl tetradecyl phosphonium chloride.

Description

0(3 INTRO~UCTION
The formation of slime by microorganisms is a problem which attends many systems. For example, lagoons, lakes, ponds, pools9 and such systems as cooling water systems and pulp and paper mill systems, all possess oonditions w~ich are conductive to the growth and reproduction of slime-forming microorganisms.
In both once-through and recirculating cooling systems, for example, which employ large quantities o~ water as a cooling medium, the formation of slime by microorganisms is an extensive and constant problem.
Airborne organisms are readily entrained in the water from cooling towers and ~ind this warm medium an ideal environment for growth and multiplication. Aerobic and heliotropic organisms flourish on the tower proper while other organisms colonize and grow in such areas as the tower sump and the piping and passages of the cooling system. Such slime serves to deteriorate the tower structure in the case of wooden towers.
In addition, the deposition of slime on metal surfaces promotes corrosion. Furthermore, slime carried through the cooling system plugs and ~ouls lines, valves" strainers 7 etc. and deposits on heat exchange surfaces. In the latter case, the impedance of heat transfer can greatly reduce the ef~iciency of the cooling system.
In pulp and paper ~i:Ll systems, slime formed by microorganisms is also frequently and, in fact, commonly encountered. Fouling or plu~ging by slime also occurs in the case of pulp and paper mill systems. Of greater significance, the slime becomes entrained in the paper produced to cause breakouts on the paper machines with consequent work stappages and the loss of production time or unsightly b~mishes in the ~ 2 - ~

~9~00 final product which results in re~ects and wasted output. The previously discussed problems have resulted in the extensive utilization of biocides in cooling water and pulp and paper mill systems. Materials which have en~oyed widespread use in such applications include chlorine, organo-mercurials, chlorinated phenols, organo-bromines, and various organo-sulfur compounds.
All o~ these compounds are generally useful for this purpose, but each is attended by a variety of impediments. For example, chlorination is limited both by its specific toxicity for slime-forming organisms at economic levels and by the ability of chlorine to react which results in the expenditure of the chlorine before its full biocidal function may be achieved.
Other biocides are attended by odor problems and hazards in respect to storage, use or handling which limit their utility.
To date, no one compound or type of compound has achieved a clearly established predominance in respect to the applications discussed. Likewise, lagoons, ponds, lakes, and even pools, either used for pleasure purposes or used for industrial purposes for the disposal and storage of industrial wastes, become, during the warm weather, beseiged by slime due to microorganism growth and reproduction. In ~he case of the recreation areas, the problem of infection, etc. is obvious. In the case of industrial storage or disposal of industrial materials, the microorganisms cause additional problems which must be eliminated prior to the materials use or the waste is treated for disposal.
Naturally, economy is a major consideration in respect to all of these biocides. Such economic considerations attach to both the cost of the biocide and the expense of its application.
The cost performance index of any biocide is derived ~rom the basic cost of khe material, its effectiveness per unit of weight 3 ~ ?o~

the duration of lts biocidal or biostatic effect in the systen treated, and the ease and frequency of its addition to the system treated. To date, none of the commercially available biocides have exhi~ited a prolonged biocidal effect. Instead, their effectiveness is rapidly reduced as the result of exposurs to physical conditions such as temperature, association with ingredients contained by the system toward which they exhibit an afflnity or substantivity, etc., with a resultant restriction or elimination of their biocidal effectiveness.
As a consequence, the use of such biocides involves their continuous or frequent addition to systems to be treated and their addition to a plurality of points or zones in the systems to be treated. Accordingly, the cost of the biocide and the labor cost of such means of applying it are considerable. In other instances, the difficulty of access to the zone in which slime formation is experienced precludes the effective use of a biocide. For example, in a particular system there is no access to an area at which slime formation occurs, and it may only be applied at a point which is upstream in the ~low system.
However, the physical or chemical conditions, e.g., chemical reactivity, thermal degradation, etc. which exist between the point at which the biocide may be added to the system and the point at which its biocidal effect is desired render the effective use of a biocide impossible.
Similarly, in a system experiencing relatively slow flow, such as a paper mill 9 if a biocide is added at the beginning of the system, its biocidal effect may be completely dissipated before it has reached all of the points at which this effect is desired or required. As a consequence, the biocide must be added at a plurality of points, and ev~n then a graduated 1 ~ ~ 9~ 3 biocidal effect wlll be experienced between one point of addition to the system and the next point downstream at which the biocides may be added. In addition to the increased cost of utilizing and malntaining plural feeo points, gross ineconomies in respect to the cost of the biocide are experienced. Specifically, at each point of addition, an excess of the biocide is added to the system in order to compensate for that portion of the biocide which will be expended in reacting with other constituents present in the system or experience physical changes which impair its biocidal activity.
The present invention relates to the use of tributyl tetradecyl phosphonium chloride in combination with the toxicant l,S-pentanedial to provide a synergistic biocidal composition.
This improved combination biocide is effective in treating micro biological problems in such industrial aqueous systems as are found in paper mills, water floods for the secondary recovery of petroleum, cooling towers and the like.
The biocidal compositions of the invention are capable of controlling the growth of bacteria, fungi, algae, and other related species.

THE INVENTION
. .
A synergistic biocidal composition useful in treating industrial process waters to prevent the growth of micro-organisms which comprises from 5 - 95~ by weight of tributyl tetradecyl phosphonium chloride (TTPC) and 95 - 5 by weight 1,5-pentanedial.
The synergistic blends described above may be used to treat a wide variety of aerobic and anaerobic bacteria. While the invention is described primarily with resp~ct to the control o~ bacteria, it is understood that the term, ~bacteria", as used herein also includes fungi and other micro-organisms The mechanisms by which chemical agents exert antimicrobial activity depend upon the ef~ective contact between the chemical and microorganism and involve disruptive interaction with a biochemical or physical cnmponent of the organism, which component is essential to its structure or metabolism~ The targets may be an enzyme, or enzymes, the cell membrane, intracellular systems, the cytoplasm, or combination of these, and the nature of the action is dependent on the organism, on the antimicrobial agent, and on the environment in which the interaction occurs. 1,5-pentanedial, for example, often acts through the alkylation of amino and sulfhydryl groups of proteins. Cationic surface active compounds such as tributyl tetradecyl phosphonium chloride form electrostatic bonds with carboxyl groups in proteins and enzymes that inter~ere with oxidation-reduction and other biochemical reactions. The cell wall is damages, lysis occurs, and metabolites leak out of the cell. Tributyl tetradecyl phosphonium chloride and 1,5-pentanedial are both power~ul toxicants to bacteria, algae, and fungi at low concentrations, as low as 1-1~ ppm of active toxicant; 1,5-pentanedial is particularly sporicidal as well.
The present invention relates to the use of tributyl tetradecyl phosphonium chloride in combination with the toxicant, 1,5-pentanedial, to provide superior antimicrobial activity through a synergy in which the disruptive interaction on the organism by the two toxicants together is greater than the sum o~
both toxicants taken alone. The synergy does not arise ~rom an expected additivity of the components or from a predictable improvement in activity. In all cases 9 the synergism depends ~ i9~0~3 largely on the interactions o~ the antimicrobial agents with the organismt the cellular processes of this latter being so compiex in these interactions as to render such synergism an unpredictable, and indeed rare, phenomenon.

E~al~a~i~n ~f tn~ In~e~ n reSt Procedure The synergism o~ these two components is demonstrated by adding tributyl tetradecyl phosphonium chloride (TTPC) and 1,5-pentanedial (PD) in varying ratios over a range of concentrations to sterile white water from a paper mill. The white water, adjusted to the desired pH, was inoculated with Pseudomonas aeru~inosa, ATC 15442. The total count o~ the control was 3.50 x 107 bacteria per milliliter. The concentrations of the above toxicants were added to aliquots o~
the inoculated white water, and these aliquots were incubated at 37C for 24 hours. In this study of the control of bacterial growth, the nutrient medium for plating was tryptone glucose extract agar, poured at 50C into sterile Petri dishes containing 1.0 ml of the white water which had been inoculated and treated as described. Once the medium in these zero dilution plates had solidifed, the plates were incubated for over ~orty-eight hours at 37C. After the incubation, the results were read as growth or no growth. The lowest concentration o~
each toxicant or of each ratio o~ the combined toxicants that prevented growth on the agar was taken as the end point. This procedure provides the toxicant with a greater challenge by testing the toxicants under conditions which approximate the conditions under which they will be used.

~93~

The test against fungi followed the same procedure with these exceptions. The white water was inoculated with Aspergillus niger to a count o~ 4.0 x 104 fungi per mill~literO The aliqùots of inoculated and treated white water were incubated at 30C for 24 hours. The medium used for plating was potato dextrose agar, acidified with tartaric a~id to a pH of 4.5. The plates ~ere incubated for over forty-eight hours at 30C. The end points of each of the ratios tested were compared with end points of the concentrations of the pure toxicants.
Synergism was determined according to the industrially-accepted method described by S. C. Kull, P. C.
Eisman, ~. D. Sylwestrowicz, and R. L. Mayer in Applied Microbiolo~y, Vol. 9, (1936), pages 538-541.

As regards the Kull, et al. document, the data here presented can be described as follows:

QA=the ppm of actives o~ TTPC alone which produced an end-point Qa=the ppm of actives of TTPC, in combination, which pro duced an endpoint.
QB=the ppm of actives o~ 1,5-pentanedial alone which produced an endpoint Qb=the ppm of actives of l,S-pentanedial, in combination, which .
produced an endpoint .

if Qa ~ Qb < 1 indicates synergy QA QB

> 1 indicates antagonism = 1 indicates additivity Ratios of TTPC/PD: 100/0, 0/100, 90/10, 10/90, 75/25, 25~75, 50~50. ,' Concentra~ions ~ested for each ratio in terms of part~ per million of ac~ives: 0.3, 0.6, 1.0, 1.5, 3.0, 5.0, 7.5, 10, 20, 30, 0, 50.

30~

TABLE I

S~a~Rt;ISM SlIJl~Y FOR COME~NA~ON aroc 1DE~ AGAINST FUNG~

+: <909~ reduction in organis~s -: ~90% reduction in organl~lDs Control Culture: 4 . 00 x 104 orqanism3 p~r ml ~atio TTP~/_PD* Con~en'crat~on ~ DIII~
.3 .~ .3 1.53.~ 5.0 7.~ io 20 - 30 ~`~4~ 50~
1 0 0 /0 ~ +
0~100~ ~ + + - ~ + +
90/10 +
1 0 / 9 0+ ~
75/25 + +
25/75 + + + ~ ~ _ _ _ _ ~ _ _ 50/50 + ~ + ~ _ _ _ _ _ _ _ _ ~0/100 does no~ show a 90~ reduction even a~ concentration~
greater than 500 ppm ac~ive Ratio ~
~, ~ Ratins 90/10 c0. 9003 ~1 Synergy 10/~0 <0. 051 <1 Synergy 75/25 ~0. 75a cl Syn~rgy 2S/75 <0 . 908 <1 Synergy 50/50 <1.030 ~1 Addi~ive or Synergy PD ~ 1, 5-pentanedial _ g _ ~9;~

¦ Calculations.

QA ~ 1. 5 ppm activ~ TTPC Q Q
Q~ ~ 500 pp~ a~:tiv~ PD a ~ b 1 ~ 5ynergy A. 90/10 B . 10/90 Qa ~ 1.5 ppm x ~90 ~ 1.35 Q~ ~ .6 ppm x .10 ~ .OS
Qb ~ 1.5 ppm x .10 ~ .15 Qb .~ ppm x .90 ~ .54 1 35 ~ 15 <0.9003 06 ~ 54 ~ <0.051 C. 75/25 Dl.25/75 Qa ' 1.5 ppm x 0.75 ~ 1,125 Qa ~ 5 ppm sc 0.25 ~ 1.25 Qb 1. 5 ppm x O . 25 ~ O . 375 Qb ~ 5 PP~ x O . 7~ ~ , 375 1.125 + 375 ~ ~0.758 1 125 ~ 3 75 a <0,90 E. 50/S0 Qa ~ 3 ppm x 0.50 ~ 1.5 Q ~ 3 ppm x 0.50 ~ 1.5 1.5~15~<1.03 TABLE II

SYNERGISM S~DY ~OR COMBINATION ~IOCID~S AGAIN~ ~3ACT}5P~IA

Growth ~ +
No Gro~th: -Control Culture: 3. 50 x lQ7 organis~ p~r ~1 }~at io TTPC/ PD Conc~ntration to~
~ . .
.~ .6 1.0 1.~ 3.0 5.0 7.5 10 ~ 30 40 50 60 on/~ + + ~ + +
0/100 + + ~ + ~ ~ ~ + +
~0/10 + I ~ ~ + ~ ~ + _ _ _ _ _ 10/90 + ~ + ~ + + ~ + + + ~ '- -7 5/2 5 + + ~ ~ ~ + + ~ + _ ~ _ _ 25/75 + + ~ + ~ ~ ~ + +
50/50 + ~ + ~ + ~ + ~ + _ _ _ _ Rat io 5 TTp-ci PD QA + ~
90/10 0. 633 <1 Synergy 10/90 0. 917 <1 5ynergy 75/25 0. 875 ~1 Synergy 25/75 0 . 625 ~1 Synergy 50/50 0. 750 <1 Synergy ~ 93~t) Calculations ~_ Q . 30 pp~ actl~ TTPC Q Q
A a ~ b ~ ynergy QE~ ~ 60 pp~ actlv~ PD ~,~ QB

A. 90flO E~. 10~90 Qa ' ~ PP~ x .90 ~ 18 Qa ~ 50 ppm x .10 ~ 5 Qb ~ 2 0 pplD x . 10 ~ 2 Qb ~ 5 PE~ . 9 0 ~ 4 S
18 + ~ ~ 0.633 5 t: 45 ~ 0.917 C. 75/2S D. 25/75 Qa ~ 30 ppm x 0 . 75 ~ 22. 5 Qa ~ 30 ppla x O . 25 ~ 7a $
Qb ~ 30 ppm x 0.25 .. 7.5 Q b~ 30 pp~ x 0~75 ~ 22~5

2.25 ~ 7.5 ~ 0.875 7.5 + 2.25 ~ 0.~25 S0 30 ~0 E. S0/50 Qa ~ 30 ppr~ x 0. 50 - 15 Q ~ 30 pp~ x 0. S0 ~ 15 15 + 15 0.75

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A synergistic biocidal composition useful in treating industrial process waters to prevent the growth of micro-organisms which comprises from 5 - 95% by weight of tributyl tetradecyl phosphonium chloride and from 95 - 5%
1,5-pentanedial.