DE2261876A1 - PRESERVATIVES - Google Patents

Description

Dr. Ing.A. νηπ ^ shipyard
ί *. fru-disüdiof ■ "· I December 8, 1972 ■

CATENTANWJt-LIf

6520/8

L. Givaudan & Cie Societe Anonyme, Vernier-Geneve (Switzerland)

Conservation Center] .

The present invention relates to methods and Preparations for preventing the growth of microorganisms in aqueous systems and. aqueous systems that rely on this Way resistant to the action of microorganisms be made.

Control of microbial growth in aqueous Systems and products poses a huge problem It is a fact that iß the aqueous systems a large number of industries are growing Such microorganisms form slime and are therefore expensive Delays and repairs arise. That `s how it is Fact that very many industrial and consumer goods as well as formulations that contain water are not only damaged , but can even be destroyed., Read through again the action of the growth of bacteria, fungi and algae.

Ur / 11/30/1972 309826/1155

Examples of such systems and compositions are industrial cooling water, Process water for pulp and paper production, flood water for secondary oil production, cosmetic products (lotions, emulsions, etc.), liquid Soaps and detergents, textile emulsions, cutting oils, polymer emulsions, latex paints, adhesives, emulsion waxes and lubricants for rolling mills.

Many preservatives have been found useful to protect against attack by these microorganisms suggested, but the known preservatives often do not give adequate protection, or are has other disadvantages, e.g. with regard to stability, toxicity, inactivation by certain components of the system to be protected, incompatibility etc.

For example, by the presence of OeI or non-ionic surfactants inactivated a large number of the known bio-oids in these systems. Next are known antimicrobial agents often only effective against certain groups of microorganisms and therefore protect systems from other types the microflora are not affected. For example, many organic silk are active against gram-positive bacteria and fungi, on the other hand show only weak or no activity at all against gram-negative organisms, such as species of the genus Pseudomonas, which occur in large quantities everywhere. the increasing demands of environmental protection and pollution control have also led to the fact that many of the well-known Organic silk, e.g. Mercury and chlorinated phenols even can no longer be used.

In the metal cutting industry where very high

When speeds are used, cutting oils are widely used for cooling, lubricating and anti-corrosive purposes.

30SQ2S / XXSS f: ι

These systems are "opposed to degradation by bacteria extremely vulnerable, and the resulting decomposition products often produce harmful odors, and often even become harmful to health Effects noted.

A cutting oil emulsion is common a 1 to 20% cutting oil emulsion in water. The emulsifiable cutting oils usually consist of Mineral oils containing additives of emulsifiers; these additives are usually a soap, a petroleum sulfonate, a. Fatty acid, a TaIköl or a resin.

The following references deal with the description of these systems, their microbiological problems and the difficulties in preventing the Growth of microorganisms in these systems: Bennet, E.O., Soap Chem. Specialties, ^ 2, 46 (1956) and Fabian, F.W. and Pivnick H., Applied Microbiology, I, 201 (1953).

Cosmetic products that contain water are also susceptible to attack by microorganisms. Detailed descriptions such formulations can be found in Sagarin, E., Cosmetic-Science and Technology, Interscience Publishers, Inc., New York (1957).

Microbial contamination of cosmetic solutions is not only associated with losses for the consumer, but also represents a health risk. The problems associated with preventing this microbial growth in cosmetics are reflected in a publication by Dunnigan, A.P., Drug and Cosmetic Industries, 102 ',' "43, (1968).

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Microbial growth in process water for pulp and paper production is a very big problem. It is therefore essential that these systems can be effectively protected against infestation by microorganisms, in order, for example, to prevent huge financial losses. Process water in the pulp industry can be up to 15 #> cellulose fibers contained, and therefore represents an extremely favorable breeding ground for microbial growth. It is made in this respect, for example, US Pat. No. 3, 397, 144.

In industry, a large number of cooling towers for cooling and recirculation purposes are becoming larger Quantities of water used. Infestation of this water by microorganisms, which usually results in slime, can cause great inconvenience. It is e.g. on Betz; Handbook of Industrial Water Conditioning, Betz Laboratiories, Inc., Philadelphia, Pa.

In the petroleum industry poses the problem of growth of microorganisms, especially the anaerobic Desulfovibrio desulfuricans poses an immense problem in the case of flood water for secondary oil production. in Meyers and Slabgi, The Microbiological Quality of Injection Water used in Alberta Oil Fields, Producers Monthly, May 12 (1966). Here you can only use antimicrobial compounds that are very effective low concentrations guarantee satisfactory protection against infestation. A recommended procedure to establish the effectiveness of a chemical compound for this purpose, consists in measuring the activity of this compound against selected bacteria: API, Recommended Practice for Biological Analysis of Subsurface Injection Water, American Petroleum Industries, New York.

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Emulsion paints (often also called latex paints) are also extremely susceptible to attack by microorganisms: Rohm and Haas: Rhoplex Acrylic Emulsions for Outdoor Paints, 11th Annual Progress Report. In this pall it is often gramnegatiye bacteria that are present in the filled Cause great damage to containers for such paints; there are harmful smells, formation of gases, discoloration, yes, even complete destruction of the emulsion. Oils and emulsions used in rolling mills are also susceptible against attack by microorganisms; E.C. Hill, Metals and Materials, 294-297, September 1967.

Lubricants used in the manufacture of synthetic and natural tissues are usually made up of various organic ingredients and water. These "lubricants" are also sensitive to attack by microorganisms, which is usually the case leads to the development of harmful odors, discoloration and disintegration of the emulsion.

Polymer emulsions are also an excellent medium for the growth of microorganisms. Such Emulsions are used in the manufacture of a huge number of products, such as paints, paper coating slips and floor coverings and printing inks are used. ■ It is in the case of these polymer emulsions, they are aqueous emulsions of thermoplastics that contain approximately 50% solids. In addition to the polymeric material such as styrene-butadiene, Acrylic products, polyvinyl acetate and polyvinyl copolymers, these emulsions often contain surfactants, Release agents, lubricants and plasticizers.

Adhesives, especially those based on starch, usually do not contain preservatives, but are just as susceptible to attack by microorganisms.

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It now became a class of antimicrobial compounds found that, after addition to the aqueous systems and compositions described above, the growth of these Bacteria, fungi and algae

effectively prevent. It has further been found that this class of compounds is much more effective against this harmful organisms is considered to be the previously known antimicrobial agents. Compared to the latter they can therefore be used in much lower concentrations.

The class of compounds in question are esters of bromonitromalonic acid; the Esters can be represented by the following formula:

0
Il
Br / C-OR

O ₂ N C-OR
0

In this formula, R represents a straight-chain or branched alkyl group with up to 4 carbon atoms.

Although some of the compounds falling under the general formula I are not new compounds are their effective antimicrobial properties and their suitability as extremely effective antimicrobial Preservatives in various aqueous systems and compositions are nowhere described, nor are they Properties suggested by any references.

The compounds in question act in both acidic and basic medium and are through Presence of non-ionic surface-active substances or large quantities of fats, oils and resins

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activated.

The compounds can be added to the aqueous systems or formulations in undiluted form or diluted with organic solvents such as alcohols, acetone, dimethylformamide, benzene, p-dioxane, carbon tetrachloride or other solvents used on an industrial scale. The addition to those to be protected Systems can be done at any point in time from their manufacture. For example, in In the case of Oei water systems, the connection to the OeI phase which is used to produce the oil-water emulsion, or the one in question Compound can also be added to the formulation already prepared.

Compounds of the formula I can be added to the aqueous systems on their own or together with other bioids and / or functional compounds such as antioxidants, anticorrosive agents, surface-active agents Fabrics etc.

The compounds of formula I are usually against a wide range of microorganisms, the aqueous Systems and formulation infested, effective. Examples of such microorganisms are:

Gram positive bacteria

Staphylococcus aureus Staphylococcus epidermidis Bacillus subtilis

Gram-negative bacteria Escherichia coli Pseudomonas aeruginosa Proteus vulgaris

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Aerobacter aerogenes Salmonella typhosa Salmonealla cholerasius

Pseudomonas fluoroescens

Yeast Candida albicans

Molds Penicillium piscarium Aspergillus niger

Äspergillus oryzae Aureobasidium pullulans

As stated above, the compounds of the formula I usually only have to be used in low concentrations. It has been found that concentrations of 0.001 to 0.1 wt. Foils already give completely satisfactory results. The use of larger quantities, although not impossible, is therefore only recommended for extremely special purposes. The preferred concentration range is that between 0.005 and 0.05 %

The compounds I can be used as preservatives for cutting oil emulsions. To this end solutions of the compounds 1 in a suitable solvent such as dimethylformamide or! ethanol ,, Created in concentrations of about 5 to about 10% by weight and these * solutions in such an amount for Cutting oil given that a concentration of about to about 30 parts of Schneidol per part of active compound arises.

The compounds I are very effective preservatives for cosmetic compositions and are particularly suitable for those formulations which contain non-ionic surface-active substances which are known to deactivate a large number of the already known bio-oils. The compounds can, for example, as such the already prepared koyruütjücken Fonnuli oriing are given odor also as a solution in A ". Ikoho 1, acetone, di-

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BATH ORIGINAL

methylformamide etc. On the other hand, the compounds I but can also be added to the oils or other raw materials used to produce the formulations.

The compounds I are just as suitable as preservatives for process water in the paper and pulp industry. Here they prevent them from being effective Way the formation of sludge. They are expediently used in these systems in concentrations of approximately 30 to approximately 250 meg per ml of process water are used. Industrial cooling water can be effectively achieved by adding about 25 to about 50 meg of compound I. per ml of water are protected against attack by aerobic bacteria.

Flood water for secondary oil production is extremely susceptible to attack by D. desulfuricans. here an addition of about 50 to about 100 meg helps Compound I per ml of flood water,.,. Aqueous emulsion dyes, such as acrylic emulsions (household dyes) are made by adding about 60 to about 125 meg of Compound I per ml Color protected in an effective way.

Similarly, non-water based oils and emulsions used in rolling mills can also be effective against attack by microbes by adding alkanolic, preferably ethanol solutions of compounds I are protected. About 30 to about are used here 60 meg per ml of the emulsion.

Lubricants can also be added by adding ethanol Solutions of compounds I are preserved. A suitable range is that of about 20 to about 125 meg of Compound I per ml of lubricant.

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Adhesives, especially those based on starch, can be added from about 20 to about 250 meg be protected by compound I per ml of adhesive.

The compounds of the formula I can be prepared by nitration of the corresponding malonic acid esters and bromination of the reaction product can be produced. If desired, higher molecular weight esters can also be obtained by transesterification of Dimethyl or diethyl bromonitromalonate with higher alcohols can be obtained. The preparation can be seen from the following reaction scheme.

COOR

COOR

ENT,

H COOR

C.
N ^ ^X COOR

Br

COOR

COOR

or:

Br / COOCH,
C.

2ROH.

Br ^ / COOR * C00R

2CH-0H

According to a preferred embodiment of the manufacturing process, which is particularly suitable for the production of diethyl bromonitromalonate or dimethyl bromonitromalonate the dialkyl malonate reacted with concentrated nitric acid at room temperature. The reaction mixture is left react at this temperature for about 1 to about 4 hours, poured onto ice water and extracted with a suitable water-insoluble solvents such as benzene, toluene etc. The organic phase is then with a

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weak base, conveniently with sodium bicarbonate washed neutral and worked up in the usual way. After removing the solvent, the residue becomes distilled under reduced pressure, the dialkyl nitromalonate transforms.

For a solution of this dialkyl nitromalonate in a lower alkanol, conveniently the alkanol, which corresponds to the alkyl group is a solution of an alkali metal alkoxide, expediently the sodium alkoxide of the alkanol used, given. A slight excess is added to this solution. in bromine and then saturated aqueous saline solution. The aqueous mixture is with a water-insoluble solvent e.g. ether and the essential extract worked up in the usual way and then the residue under reduced Pressure distilled j, giving the desired dialkyl bromonitromalonate is received «,

As stated earlier, higher dialkyl bromonitromalonates by transesterification of dimethyl or diethyl bromonitromalonate with higher alcohols in the usual way can be obtained.

To 80 g of diethyl malonate ml of concentrated nitric acid * at 15-2o C ⁰ 3.84 is slowly added and the reaction mixture stirred for 3 hours at this temperature, the nitrated ester is added to 1 liter of ice water and hJß up the mixture twice with 200 ml of toluene The toluene extracted "Extract is washed neutral by adding aqueous sodium bicarbonate and water ^ dried over magnesium sulfate and filtered" The toluene is removed on a rotary evaporator and the residue is vacuum distilled _ρ with the

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BAD ORUSlNAt

Diethyl nitromalonate passes over at 97-99 ° / l, 7 min Hg. A solution of 1.2 g of sodium in 75 ml of absolute ethanol is slowly added with stirring to 10 g of diethyl nitromalonate in 75 ml of absolute ethanol, at a temperature of ⁰ ° C. 8 g of bromine are slowly added to the reaction mixture while stirring followed by the addition of 200 ml of a saturated solution of common salt. The aqueous phase is extracted three times with 200 ml of ether each time, and the combined ether extracts are dried over magnesium sulfate and then filtered. The ether is then removed on a rotary evaporator and the residue is distilled in a vacuum. The diethyl bromonitromalonate (I) boils at 143-145 ° C / 15 mm Hg.

In an analogous manner, using the appropriate starting materials, the following malonic esters are obtained obtain:

Dimethyl-bromnitromalonat (II), bp. 128-129 ⁰ C.

Λθ mm Hg..

Di-n-butyl-bromnitromalonat (III), bp. 120 ⁰ C / 0.1 mm Hg.

Di-n-propyl-bromnitromalonat (IV), bp. 82.5 C ⁰ /0.01 mm Hg.

Example 2

To the effectiveness of the compounds used according to the invention as preservatives for cutting emulsions To illustrate, the following bacteriological experiment was carried out:

Serial dilutions were made for each compound to be evaluated starting from a violin solution in ethanol manufactured. Two cutting emulsions were made the first by diluting one part of Kutwell 30.

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2281876

oil with 100 parts of distilled water and the second by diluting one part of Kutwell 30 cutting oil with 30 parts of distilled water. Kutwell 30 Cutting Oil (Humble Oil and Refining Co.) is an emulsifiable sulfonated lubricant that is used as a cooling solution in turning, cutting and grinding metals. The oil was diluted with distilled water-rich peptone (Difco), the final concentration of this peptone in the emulsion that was sterilized being 0.1 % . Aliquots (0.1 ml) of the dilution series were added to each 12 ml of the cutting oil emulsion. The samples were inoculated with a drop (0.05 ml) of a 24 hour old culture of Pseudomonas aeruginosa and ^{incubated at 28 °} C. on a mechanical shaker. The survival of the microorganisms was determined weekly for 4 weeks. The samples were re-inoculated after each sampling, so that each had been inoculated a total of four times at the beginning of the fourth week. The survival of the microorganisms was determined by spreading 0.01 ml of emulsion onto the surface of trypticase-glucose extract agar which contained 0.005% triphenyltetrazolium chloride and letheenantidote. The anti-growth concentration of the test compound was noted.

Table I.

It gives the minimum inhibitory concentration of compound _. which completely prevents the growth of Pseudomonas aeruginosa in the emulsion, again (μg / ml). Connection 1st week 2nd week 3 »week 4 week ^αυ ' 1: 100 l:? 0 1: 100 1: 3Q 1: 100 1:30 1: 100 1:30 I 15.6 15.6 15.6 15.6 31.25 31.25 31 * 25 31.25

II 15.6 15.6 15.6 15.6 15.6. 15.6 15-6 15.6

III 250> 50O 250 500 250 500 250 500 IV 125 250 125 250 125 250 125 250

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Example 3

The compounds used according to the invention offer a protection against the development of microorganisms in cosmetic preparations. To demonstrate this, were the compounds in dimethylformamide added to the following cosmetic lotions:

Formulation A

Stearic acid 1.4

Mineral oil 2.3

Arlacel 60 (sorbitan monostearate) 0.7

Tween 60 (polyoxyethylene sorbitan monostearate)

water

Dishes

1.6

94.0

Formulation B Tetrahydrosqualene Alcolec 4135

Polyethylene glycol 400 monostearate

Cetyl alcohol water

Parts by weight 5.2 1.6

2.1

1.1

90.0

Formulation C stearic acid Tween 60
Amerchol L-IOl Modulan
Chip 60
water

Parts by weight 3, Q 2.9 6.0 2.0 2.1 84.0

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. - 15 -

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Formulation D G weight parts

Mineral oil. 30.0

Cetyl alcohol 1.0

Amerchol L-IOl 5.0

Arlacel 165 4.0

Solulan 98 \ 2.0

Glycerin 4.0

Water 54.0

To ensure good growth of all test organisms, a nutrient solution was added to the finished emulsion, so that each 0.1 $ Peptoii, yeast and malt extract. All formulations (they contained various amounts of the compounds used according to the invention) were created in duplicate, one series with a spore suspension of Aspergillus niger and the other was inoculated with a 24 hour old ferry solution of Pseudomonas aeruginosa. It is "with these Organisms and microorganisms that are very common in cosmetic products. The samples were 4 weeks incubated, observations being made to establish the protection of the test substrates at appropriate intervals became. The samples were also reinoculated with the test organisms at weekly intervals. The growth the fungi became macroscopic, that of the bacteria means the method of Example 2 demonstrated. The results of these tests, i.e. the respective minimum inhibitory concentrations during the 4 week incubation period are the following:

Minimum inhibitory concentration (mg / ml)

Compound Form- Form- "Formu- Formu-

Ho - ling A ling B. lation Q lation D

Ps.a. To . Ps.a. To Ps.a. To Ps.a. A.η,

I <30 <30 60 500 <30 < 30 <30 <

II <30 <30 <30 C30 <30 <30 <30 <

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22 * 1876

Example 4

To the activity of the used according to the invention "Compounds against microorganisms in process water for to prove the pulp and paper production, a in Microbiology of Pulp and Paper, ΤΛΡΡΙ Monograph Series, No. 15 used test. For this purpose the compounds were dissolved in dimethylformamide and adding constant volumes of the dilution series to containers containing 24 ml of the following substrate:

8.4 g Whatman No. 2 pulveris. Cellulose 2.6 g sodium nitrate

1.0 g calcium sulfate

6.5 g maltose 1.0 g nutrient solution, Difco 10.0 ml 2% Mersize RM 7OR (Monsanto)

2.5 ml 2% alum

900 ml dist. water

The containers were with. One drop each of an 18 to 24 hour old nutrient solution of the bacteria or an aqueous conidia suspension (the fungi were grown on potato- dextrose agar). The samples were hut at 28 ⁰ C on a mechanical IJC! Incubated .Machine.

The bacterial Ic growth was determined after 7 days by means of para t r i c h e au Γ T r y ρ t i c a s e - G Iu c ο s e -E χ t r a k t -

Agar (with Lo the cm) recorded. The growth of the fungi has been also after a 7-day period

ν i rs 11. ο 13 Yi ac} \ / ■; ο \: i. ο: ~; ο η. J) i .. ο f '·. irdi ο π ο η V er ί 'uc Ii used

Control Leu pointed uacli (iiesei- .perio ^ G strong

W'a.c;! I! ^: rtum on. In the i'olgetideü Ta.briVh; are dJ.e rai.niin'vlen Jji: n: n] roji ^ c]] i.ra1,: i onan der · connection ^ on ;; u ;; a ;;:!; ion ₍ ';el'a , si3t:

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BATH ORIGINAL

Inhibitory concentration (nicg / inl)

I. II III 'IV 62 31 250 125 62 31 125 62 62 31 125 125 62 31 125 125

Organism Ps. Aeruginosa A. aerogenes A. niger
P. piscarium

The compounds used according to the invention can be added directly to the systems described above or in solution be added in different solvents, with solutions also other bio-oils and / or additives, which are used for process water in the · pulp and paper production, can be combined.

Example 5

The compounds used according to the invention effectively prevent the growth of microorganisms in industrial cooling water, which can be demonstrated by the following experiments! A sample of ύοχι industrial cooling water was taken from a system that had been in operation for several years. The installation in question consisted of a cooling tower with ancillary equipment; with the cooling system 9080 liters of water was cooled per minute from 35 ⁰ C to ⁰ C 29.44. The system was made of California wood and contained plastic fillings; the capacity was 37,850 liters. The water sample taken was divided into several aliquots (150 ml) and solutions of the compounds used according to the invention in dimethylformamide were added to these parts. Only dimethylformamide was added to one sample (control). The total amount of aerobic bacteria was determined at the beginning and then again after a 24 hour incubation period (mechanical shaking machine). The results are as follows:

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0 Compound I. 00 24 hours) O link II Konc./mcß/ml 53 χ ΙΟ ⁴ 143 x ΙΟ ⁴ 53 (h) 24 (η) 79 χ ΙΟ ⁴ O 52 χ ΙΟ ⁴ 143 χ 10 0 52 χ ΙΟ ⁴ O 101 χ. ΙΟ ⁴ O 25th Example 6 χ ΙΟ ⁴ O 50

The activity of the compounds used according to the invention of formula I against D. desulfuricans under anaerobic conditions when using a Difco-sulfate API nutrient solution was decided. The compounds were as dilution series (solution in dimethylformamide) on the Given medium and incubated the medium at 27 ° for 30 days. After this period, a visual examination was carried out. From the below It can be seen from the table that the compounds used according to the invention are also effective against this microorganism Can be used effectively.-The compounds are the flood water, conveniently dissolved in aliphatic or aromatic solvents.

link Minimal inhibitory concentration
(mcff / ml) I. 50 II 50 III 100 IV 50

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Example 7

The following experiments would "prove that the compounds of the formula I can be used as preservatives suitable for emulsion dyes. An emulsion dye (acrylic emulsion) was chosen for this purpose, which did not contain any preservatives. The composition of the paint was as follows:

water 20.7 Daxad 30 0.8 Triton X-IOO 0.2 Clearate TO 10.4 Ti-Pure 11-901 25.0 Lorite • 30.0 Duramite 10.0 Wallastone P4 5.0 2fo QP 15000 Sol. 12.7 Ethylene glycol 2.0 Everflex BG- 27.0 Texanol 1.8

The compounds used according to the invention were added to this formulation in a variable concentration in ethanol, and the specimens with a color showing large amounts of Pseudomonas aeruginosa was inoculated. The preferential life of the bacteria in the various samples was determined by that Subscribe to Dextrose Trypticase Extract Agar, initially and after 24 hours, 1, 2 and 4 weeks, «The Results are the following «

link 24 H Minimal hemin concentratex
(mc / i / ml on No , 5
, 5 1. Before 2 weeks / ■ Weeks I.
II <62.5 ^ 62.5 ■ <.
<f)? .. b <62.5 62 r; η οι;

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Example 8

The usability of the compounds as Bioeide in Oils or emulsions for rolling mills was demonstrated by the following test. A corresponding emulsion was made by diluting a commercially available concentrate, namely Prisol 44 (Mobil Oil Co.), in a ratio of 1:20 with water manufactured. $ 0.1 peptone and small was added to the emulsion Amounts of aluminum and steel filings are given to simulate conditions of use. Different concentrations of the compounds used according to the invention were to given to the emulsions in the form of ethanol solutions. The solutions were then mixed with samples of gram-negative microorganisms incubated in a contaminated emulsion from a rolling mill. Samples were kept on a shaker and weekly checked for the growth of microorganisms as described above and reinoculated each time. After 4 weeks the following picture emerged:

link
No Minimal inhibitory concentration
(rncg / ml) Example 9 I. 62.5 "II

The effectiveness of the compounds against microorganisms in "spin finishes" (lubricants) was based on of a Nopco 1296 (Nopco Chemical Co.) lubricant concentrate. The lubricant was in a ratio of 1: 4 with Diluted water and various concentrations of the invention Compounds used as ethanol solutions are added. The emulsions were with a Microorganism nutrient solution inoculated, which nutrient solution

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Contained contaminated "spin finishes" from a textile factory. The samples were incubated on a shaker kept and checked weekly for microbial growth and reinoculated each time. After 4 weeks revealed the following picture emerges:

link
No Minimal inhibitory concentration
(mcg / inl) Example 10 I. 125 II 31

The suitability of the compounds as preservatives for polymer emulsions was demonstrated by means of a test on an acrylic emulsion. Various concentrations of the compounds were added to samples of a "Rhoplex B-15" acrylic emulsion (Rohm and Haas) in an ethanol solution. The samples were inoculated with a culture of Pseudomonas aeruginosa and kept in a closed container at 28 ^° C. for 4 weeks. The presence of surviving bacteria was determined weekly by swabbing as described above. After each swab, the samples are reinoculated. The results of these experiments, ie the minimum inhibitory concentration which prevents the survival of the bacteria over the entire period of time, can be summarized as follows:

Compound Minimum Inhibitory Concentration No (mog / ral) ■

I 62.5

II 31.3

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Example 11

It is known that adhesives which do not contain any preservatives, especially starch-based adhesives, often decompose. The effectiveness of the preservatives used according to the invention for the preservation of such starch adhesives was demonstrated as follows: A 6 strength corn starch solution, polygamy was ^{partially hydrolyzed by heating to 100 °} C. for 5 minutes, was inoculated. In order to ensure good growth of the test organisms, the starch was mixed with nutrients so that it contained 0.1 $ each of malt extract and peptone.

The compounds to be tested were added to the samples as dimethylformamide solutions. Pure any concentration a duplicate was produced and using a pure culture with Pseudomonas aeruginosa, Aspergillus niger and Penicillium piscarium. The samples were incubated at 4 weeks and then checked for microbial growth checked. Pseudos aeruginosa was detected by smears as described above, Aspergillus niger and P. piscariuiri was detected macroscopically. The results are as follows:

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Incubation (4 weeks )

^ indung WmI). Ph. Aeruginosa iUniger P.piecarium

I 250. - -.

I 125 - ~

I 62.5- - -.

I 31.3 +. '+

I 15.6 · ■ + - + ⁺

Ii 250 _.._--

II 125 - - -

II 62.5 ■ -

II 31.3 - + '-

II 15.6 '++

- = no growth + = growth

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Claims (1)

Pa t e η t an s ρ rü ehe (i) means for preventing the growth of ^{vy therethrough} Microorganisms in aqueous systems, / characterized that it a microbiocidally effective amount of a dialkyl bronmitromalonate the formula 0 Il Br / C-OR OJT C-OR where R is an alkyl group with up to Represents 4 carbon atoms, and contains a carrier material. 2. Means according to claim 1, characterized in that that it contains as a compound of formula I Mäthylbromnitromalonat. 3. Means according to claim 1, characterized as
that it / compound of formula I Dime thy lbroinnitromalonat. contains. 4. Resistant to microorganisms composition, characterized in that it is an aqueous system that the Is subject to destruction by such organisms, and a microbiocidally effective amount of dialkyl bromonitromalonate the general formula 0 Ii Biv C-OR ^x n ^ T V / JL O ₀ IK ^ C-OR ² Il wherein R is an alkyl group with up to Contains 4 carbon atoms. 3 0 9 8 2 6/1155 5 «Composition according to claim A _9, characterized in that the aqueous system is an aqueous cutting oil emulsion, an aqueous cosmetic emulsion, process _{water in pulp and paper production, industrial cooling water 9} flood water for secondary oil production, an emulsion paint, an oil used in rolling mills or a corresponding one Emulsion _{p represents} a lubricant, a polymer emulsion (an aqueous emulsion of styrene-butadiene ~ or acrylic polymers, polyvinyl acetate or polyvinyl copolymers) or starch-based adhesives » 6. Method of preventing the growth of microorganisms in aqueous systems, characterized in that these systems are given a microbiocidally effective amount of a dialkyl bromonitromalonate the ilormel Br. C-OR
C. wherein R represents an alkyl group with up to 4 carbon atoms,
admits. . 7. A process according to claim 6, characterized in that 0.001 to 0.1 wt.% Of Dialkylbromnitromalonats be used. 8. The method according to claim 7, characterized in that about 20 to about 250 meg dialkyl bromonitromalonate / ml aqueous system can be used. 9. The method according to claim 6-8, characterized in that the aqueous system is an aqueous cutting oil emulsion, a 309826/1155 aqueous cosmetic emulsion, process water in the pulp and papermaking, industrial cooling water, flood water for secondary oil production, an emulsion paint, one in rolling mills used oil or a corresponding emulsion, a lubricant, a polymer emulsion (an aqueous emulsion of Styrene-butadiene or acrylic polymers, polyvinyl acetate or Polyvinyl copolymers) or starch-based adhesives. 10. Use of dialkyl bromonitromalonates of the formula 0
Br ^ G-OR OpN "^ C-OR I wherein R represents an alkyl group with up to 4 carbon atoms, to prevent the growth of microorganisms in aqueous systems. 11. Use according to claim 10, characterized in that ekennzeich.net, that the aqueous system is an aqueous cutting oil emulsion, an aqueous cosmetic emulsion, process water in the pulp and papermaking, industrial cooling water, flood water for secondary oil production, an emulsion paint, one in rolling mills used oil or a corresponding emulsion, a lubricant, a polymer emulsion (an aqueous emulsion of styrene-butadiene or acrylic polymers, polyvinyl acetate or polyvinyl copolymers) or is starch-based adhesives. 12. Use of dimethyl bromonitromalonate for prevention the growth of microorganisms in aqueous systems. 13. Use of diethyl broinnitromalonate for prevention 309826/1155 the growth of microorganisms in aqueous systems. 309826/1 155