LU84345A1 - METHOD FOR CONTROLLING THE ALTERATION OF TECHNICAL LIQUIDS USING NITROIMIDAZOLE DERIVATIVES - Google Patents

Description

(*

The present invention relates to a method for combating the deterioration of technical liquids caused by strict anaerobic bacteria which are suifatoreductive, and to compositions suitable for this fight.

j- The deterioration of technical liquids (either organic liquids containing water, or aqueous liquids containing organic products), caused by the proliferation of microorganisms * which metabolize the organic product with parallel formation of harmful metabolites, is a widespread problem in many industries 10. This growth of microorganisms requires the presence of free water in the organic liquid (oil for example) since, although the microorganisms can often pass into the organic phase, their growth and their activity are mainly confined in the aqueous phase. It is practically impossible to exclude from the organic liquid the small initial quantities of water required for the start of the growth of microorganisms and, in fact, water is deliberately incorporated, in greater or lesser quantity, in many organic liquids used in industry.

A wide variety of bacteria, molds and yeasts are responsible for the alteration of body fluids, and it is practically impossible to exclude all of these microorganisms from such liquids. As examples of organic liquids and aqueous liquids * containing organic products subject to bacterial deterioration, mention may be made of mineral and vegetable oils and “industrial liquids which contain them, in particular combustible oils, lubricants, hydraulic fluids based on mineral oil, oil in water emulsions (O / W, for example cutting oils), water in oil emulsions (W / Η, for example hydraulic fluids based on these 30 emulsions), aqueous solutions and emulsions of glycols used as machining fluids.

if ft 2 \ Other aqueous liquids containing organic products subject to serious bacterial spoilage include water-based paints, residual pulp solutions with sulfite, and even predominantly inorganic fluids such as water treatment, electroplating solutions and injection water for oil wells.

The deterioration of organic liquids and aqueous liquids containing organic matter (for example mineral or vegetable oils) due to bacterial proliferation can have the effect of: 10 - the corrosion of metallic tanks (for example during the storage of fuels, extraction and processing of mineral oils) or machine tools (for example in the machining, drilling, grinding and rolling of metals), the alteration affecting the working fluids used as lubricants 15 and coolants in metalworking; - the decomposition of additives in lubricating oils, with the consequence of reducing the lubricating properties of oils; - reduction of emulsifiers of the sulphate or sulphonate type, reduction or oxidation of emulsifiers and corrosion inhibitors. containing nitrogen, with consequent deterioration or instability of the O / W and W / O emulsions 5 - reduction of the oil / water interfacial tension in the fuel tanks, which results in poor separation * 25 of the water and fuel contamination by this water; - the clogging of pipes, filters and orifices by bacterial bodies.

The oxygen content in body fluids and aqueous fluids containing organics used in the industry is often low and can be further reduced by the growth of aerobic or optional aerobic microorganisms, which promotes the growth of anaerobes strict sulfato-reducers “+ / 3 4.

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In the present text "strict anaerobic sulfato-reducer" designates a strict anaerobic microorganism capable of metabolically extracting oxygen from a compound which contains sulfur in the oxidized state by bringing it to a reduced state (generally hydrogen sulfur) or capable of metabolically reducing elemental sulfur to * hydrogen sulfide. Examples of strict anaerobic bacteria responsible for industrial alterations include: Desulfovibrio: desulfuricans, Desulfovibrio gigas and Desulfotomacuïum nigrificàns (Clostridium nigrificàns or Desulfovibrio orientis).

10 Strict sulphator reducing anaerobes metabolically reduce sulphates and sulphonates such as emulsifiers containing sulphates and sulphonates, for example emulsifiers based on alkyl sulphates and alkylarylsulphonates, sulfur oils and fats and sulphate ions present in water, with release of hydrogen sulfide. This results in particularly severe problems of deterioration in organic liquids and in aqueous liquids containing organic products / for example mineral and vegetable oils (combustible or lubricating oils), hydraulic fluids based on mineral oil, H / Fe emulsions. (machining fluids), for example 20 W / O emulsions / (hydraulic fluids), aqueous glycol solutions or emulsions used as machining fluid. /, with the production of offensive odors, corrosion due to the release of hydrogen sulfide and destruction of emulsifiers, which leads to deterioration and instability * of the emulsions.

. 25 Strict sulphate-reducing anaerobic bacteria cause similar problems in sulphite pulp waste water, water paints, oil injection water, waste water, electroplating solutions, sealed cooling circuits (30 heat exchangers and water heating and cooling systems), hot water storage / distribution systems, and in water seals for gas meters.

4

This deterioration causes particularly troublesome problems in the water which settles at the bottom of the tanks of heating oils and in the injection water for oil drilling.

O / W emulsions and aqueous solutions or emulsions of glycols used as machining liquids, for example as coolants for rolling mills or machine tools, which contain mineral or vegetable oils or glycols, are emulsifiers, corrosion inhibitors and water with, if desired, greases, soaps and small amounts of special additives serving as plasticizers, defoamers and high pressure additives are widely used in metalworking. These liquids perform a number of functions, in particular lubrication and reduction of the temperature at the workpiece-tool interface, prolongation of the life of the tool, elimination of chips and filings, and cooling of the metal sheet during rolling or stamping operations. For reasons of economy it is essential that the machining liquid can be recycled. Such a liquid normally contains 1 to 15% by volume of oil and / or glycols and is used at temperatures ranging from room temperature to 40-60 ° C. So machine tool coolants operate at temperatures just above the ambient? Their oil and / or glycol content varies from 1% in grinding coolers (where the elimination of heat, in order to maintain dimensional accuracy, is of primary importance) to 15% in the operations of severe machining where lubrication is an essential necessity. Coolants for rolling mills generally have an oil and / or glycol content of 2 to 5% and work at a higher temperature, often from 40 to 60 ° C.

These machining liquids are quite sensitive to bacterial contamination and their oxygen content often becomes very low, especially when the liquid is not in use. This fact promotes the growth of strict sulphate-reducing bacteria, which brings about the problems mentioned above.

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The fight against this bacterial alteration is therefore of major importance for the recycling of various machining fluids.

Attempts have already been made to prevent this alteration by the incorporation of various biocides, but the properties required of a satisfactory product are extremely severe and relatively few of them have been commercially successful. Thus such a product, apart from its effectiveness in destroying or inhibiting the growth of microorganisms, must preferably be non-toxic and non-irritant, have a satisfactory stability over a suitable period of time in the appropriate temperature and pH ranges, have preferential solubility in water to find it at an adequate concentration, non-preferential solubility in the organic phase, and be compatible with the system to be protected (for example, do not affect the characteristics and ± 5 stability of emulsions, do not cause foam or foam, do not change the pH of the system and, in the case of heating oil or in machining, do not produce undesirable ash during combustion).

Various phenols have already been used (e.g. p-chloro m.-20 cresol and phenol), heavy metal compounds, formaldehyde generating products and other biocidal products, with varying degrees of success, but the safety of use of many of them have been questioned. There is therefore a continuing need for a new method of combating alterations due to the growth of strict anaerobic bacteria which are sulfato-reducing.

It is known that 1 '(2-hydroxyethyl) -1 2-methyl-5-nitro-imidazole (hereinafter referred to as "metrononazole"), 1,2-dimethyl-5-nitroimidazole (hereinafter "dimetridazole") , 1 '(2-hydroxy-propyl) -1 2-methyl-5-nitro-imidazole (hereinafter "secnidazole") and 1-methyl-2-isopropyl-5-nitro-imidazole (hereinafter "ipronidazole") are active against protozoa, amoebae and certain anaerobic bacteria which can infect humans and animals. Z / 4 6

Strictly sulfa-reducing anaerobic bacteria are not a recognized cause of infections in humans and animals, and to date it has not been suggested that these products be effective against strict sulfa-reducing anaerobic bacteria in human or or that they are effective in combating the deterioration of technical fluids caused by the above bacteria.

. ^ Metronidazole, dimetridazole, secnidazole and ipronidazole therefore did not present themselves to specialists in search of new ways to combat the deterioration of industrial liquids due to these microorganisms, and it did not appear that these products have the combination of other properties necessary for them to be used successfully.

It has now been unexpectedly found that the nitroimidazole derivatives of dimetridazole, metronidazole, secnidazole and ipronidazole can be used in this fight. It is understood that the term "derivatives of nitroimidazole." used below denotes dimetridazole, metronidazole, secnidazole and ipronidazole.

The present invention therefore relates to a method of combating industrial contamination caused by strict anaerobic sulfato-reducing bacteria in organic industrial liquids containing water or in aqueous industrial liquids * containing organic products, this method comprising incorporation into the aqueous phase of a sufficient amount of at least one nitroimidazole derivative according to the invention to prevent the growth of said bacteria.

The concentration of nitroimidazole derivatives (which, according to the invention, can be used separately or simultaneously) is generally between 3.00 and 500 ppm (more especially 100 ppm) relative to the total volume of the liquid to be protected. However, lower or higher concentrations can be used, depending on the particular problem to be solved, the suitable concentration easily determined by suitable tests. / jy 7

Nitroimidazole derivatives do not have preferential solubility in the organic phase of organic liquids containing water or aqueous liquids containing organic products, they are sufficiently soluble in the aqueous phase to give effective concentrations preventing the proliferation of said bacteria, they are neither toxic nor irritating, unlike most agents previously used for the same purpose, they have satisfactory stability for a sufficient time in the appropriate temperature and pH ranges, they do not affect the characteristics or the stability of Η / E or E / Η emulsions, does not cause foaming or foaming, does not affect the pH and is not a source of undesirable ash.

The nitroimidazole derivatives according to the invention can be added as such to the industrial liquids to be protected, but they are preferably added in the form of solutions, suspensions or emulsions in suitable solvents such as water, glycols (for example ethylene glycol), dimethylformamide, dimethylacetamide, liquid hydrocarbons (eg kerosene) and mixtures thereof which may, if necessary, contain one or more surfactants.

A suitable formulation consists, for example, of a suspension prepared by mixing the following ingredients (weight / volume): dimetridazole microfin 25% 25 Texofor M6 4%

Arylan CA 6%

Attagel 50 '1% Kerosene (deodorized) qs 100% by volume Texofor Mô is an ethoxylated oleic acid containing 6 moles of ethylene oxide per mole of oleic acid; Aryan CA is calcium dodecylbenzenesulfonate / ------— ÿ.

The invention also relates to concentrates making it possible, after dilution with the appropriate quantity of water, to prepare machining liquids which contain the oils and / or glycols, emulsifiers and corrosion inhibitors usual in these concentrates 2 and a proportion of nitroimidazole derivatives sufficient to give, after dilution, the desired concentration in the machining liquid obtained. The concentrate generally contains 0.05 to 5% W / V of derivative - nitroimidazole.

If desired, the nitroimidazole derivatives according to the invention can be used in combination with known agents as mentioned above, for example phenols, heavy metals or formaldehyde generating products.

The nitroimidazole derivatives according to the invention also make it possible to combat alteration caused by nitrato-reducing and nitritoreducing bacteria in industrial liquids (organic and containing water, or aqueous and containing organic materials).

The advantageous properties of the nitroimidazole derivatives according to the invention are demonstrated in tests 1 to 4 below: Tests 1 to 4 - Activities against strict sulfa-reducing anaerobic bacteria Method I - The products tested are incorporated (by adding the appropriate quan tity of their aqueous solution at 5000 ppm) at concentrations of 50, 100, 250 and 500 ppm in an O / W emulsion highly contaminated with sulphate reducing bacteria (previously samples of contaminated emulsion, free tested products, which will serve as controls). Samples of the contaminated oil are taken immediately after the addition of the test product, and after 3.5 and 24 hours.

Iron sulfite agar (Oxoid Ltd) is prepared and distributed into tubes (10 cm 3 per tube). It is sterilized in an autoclave under 1 bar (10 kPa) for 15 min and the tubes are capped with J Astell caps which provide a hermetic seal and / / thus allow anaerobic growth. A / f h 4 9

The tubes are placed in a water bath at 50 ° C to maintain the agar in the liquid state, inoculated with a loop (l / 50 cm3) of the contaminated O / W emulsion and incubated at 37 ° C for 5 days.

The tubes are then rated according to the following scale: 5 +++++ completely black - no inhibition; * ++++ grows well, but not completely black +++ gray / black spots of inhibition and grows ++ gray with black spots + light except a few black spots 10 0 clear - complete inhibition

The following results are obtained:

Trial 1 (a) Metronidazole '

Concentration contact time with metronidazole 15 in metronidazole Immediately 3 hours 5 hours 24 hours 0,. . +++++ +++++ +++++ +++++ (control; 50 ppm +++++ +++++ +++ ++ '100 ppm +++++ ++ +++ ++ + 25Ο ppm ++++ +++ - + .0 20 500 ppm +++ ++ + 0 (b) Dimetridazole

Concentration contact time with dimetridazole to dimetridazole Immediately 3 hours 5 hours 24 hours 0. , +++++ +++++ +++++ +++++ (control; 25 50 ppm +++++ ++++ ++++ +++ 100 ppm ++++ + ++ ++ + 250 ppm ++++ ++ + 0/500 ppm +++ + 0

V

10 y

Trial 2 (a) Metronidazole

Concentration contact time with metronidazole to metronidazole Immediately 3 hours 5 hours 24 hours 0 5. ,. ++++ ++++ ++++ ++++ (control) „· 100 ppm ++++ +++ + + 200 ppm ++++ ++ + +

500 ppm +++ + + O

(b) Dimetridazole 10 Concentration contact time with dimetridazole to dimetridazole Immediately 3 hours 5 hours 24 hours 0, ++++ ++++ ++++ ++++ (control) 100 ppm ++++ ++ + + 0 200 ppm +++ +0 0 15 500 ppm +++ 00 0

Trial 3 (a) Metronidazole

Concentration contact time with metronidazole to metronidazole Immediately 3 hours 5 hours 24 hours 20 25 ppm ++++ +++ +++ +++ 50 ppm ++++ +++ +++ +++ 100 ppm + +++ +++ + + (b) Dimetridazole contact time with dimetridazole

Concentration Immediately 3 hours 5 hours 24 hours 25 of dimetridazole 15 ppm ++++ +++ ++ ++ / 50 ppm ++++ +++ ++ ++ / // I- 11

Test 4 Method II

In flasks containing 100 cm3 of aqueous solution at 50,100,250 or 5OO ppm of the product to be tested, 0.1 cm3 of an O / W emulsion 5 highly contaminated with strict anaerobic sulphonator-reducing bacteria is added. A control flask is also prepared without the product to be tested. Samples are taken: - from the control flask, immediately after adding the oil - from all the flasks, after 3, 5, 24 and 48 hours.

10 Iron sulphite agar (Oxoid Ltd) is prepared and distributed in tubes (10 cm 3 per tube). We sterilize in an autoclave 2 under 1 bar (10 kPa) for 15 mm and cap the tubes with Astell caps which ensure a hermetic closure and thus allow anaerobic growth.

The tubes are placed in a water bath at 50 ° C to maintain the agar in the liquid state, seed with a loop (1/50 cm3) of the contaminated O / W emulsion and incubate at 37 ° C for 7 days. The action of the products tested is noted on the strict anaerobic sulfatoreductive bacteria present in the contaminated emulsion, as described above. The following results are obtained: (a) Metronidazole * *

Concentration contact time with metronidazole to metronidazole Immediately 3 h. . '5:24 a.m.' ·. 48 h 0 · r,,. ·, +++++ +++++ +++++ +++++ +++++ (witness) 25 50 PPm - +++++ '++++ +++ ++ 100 ppm - +++++ +++ + 0 250 ppm - ++++ ++ 0 0 500 ppm - +++ + 0 * 12 (b) Dimetridazole

Concentration contact time with dimetridazole to dimetridazole Immediately 3 h 5 h 24 h 48 h 0 /,. s + + + + + 4 · + + + + + + + + + + + + + + + 4 * 4 * 4- + (witness). . 5 50 ppm - +++++ ++++ + + + ++ 100 ppm - +++ ++ + 0 to * 250 ppm - ++ + O 0 500 ppm - +000 (c) Ipronidazole 10 Concentration time contact with 11ipronidazole as ipronidazole Immediately 3 h 5 h 24 h 48 h 0. ,. > +++++ +++++ +++++ +++++ +++++ 1 witness; 50 ppm - +++++ ++++ +++ ++ 100 ppm - ++++ +++ ++ + 15 25Ο ppm - +++ ++ + 0 500 ppm - +++ +00 ( d) Secnidazole

Concentration of contact time with secnidazole to secnidazole Immediately 3 h 5 h 24 h 48 h ’* ™ 0 20. ,. +++++ +++++ +++++ +++++ +++++ (control) '50 ppm ”+ ++++ +++++ ++++ +++ 100 ppm - ++ +++ ++++ +++ + 25Ο ppm - ++++ ++ 0 0 500 ppm - +++ + 0 f,., »13 (e) Kathon MW 886

Concentration contact time with the Kathon MW 886 in Kathon MW 886 Immediately 3 h 5 h 24 h 48 h 0, +++++ +++++ +++++ +++++ +++++ ( control) 5 50 ppm - +++++ ++++ +++ ++ 100 ppm - +++++ 4 - ++ 4- +++ + 25Ο ppm - ++++ +++ ++ 0 500 ppm - +++ ++ + 0 (f) Grotan TK2 10 Concentration contact time with Grotan TK2 in Grotan TK2 Immediately 3 h 5 h 24 h 48 h 0 ,,,. , +++++ +++++ +++++ +++++ +++++ (control) 25Ο ppm - +++++ ++++ +++ ++ 500 ppm - + +++ ++++ +++ ++ 15 750 ppm - +++ ++ + 0 1000 ppm - +++ + 00 (g) Bodoxin

Concentration of contact time with Bodoxin '' in Bodoxin Immediately 3 H 5 h 24 h 48 h 0 * 20 t λ. ' · \ +++++ + +++ + +++++ + + + + + +++++.

(control) 250 ppm - + + + + + ++++ + + + + + 500 ppm - ++++ +++ ++ + 750 ppm - +++ ++ + 0 1000 ppm - ++ + 0 0 25 Kathon MW 886, Grotan TK2 and Bodoxin are commercial industrial biocides, used to combat strict sulfator-reducing bacteria / anaerobes. / d / r 14

The results obtained in tests 1,2,3 and 4 confirm that metronidazole, dimetridazole, ipronidazole and secnidazole inhibit the production of sulphide by the strict anaerobic bacteria sulphoratrix, the effective concentration 5 in these tests there being 4 100 ppm. The effective concentration for Kathon MW 886, which can cause severe irritation to the skin and eyes, is also close to 100 ppm. For

Grotan TK2 and Bodoxin the effective concentration is higher, around 500 ppm * 10 The compatibility of the nitroimidazoles according to 11 invention · with machining fluids of the O / W emulsion type, prepared from commercial concentrates, is demonstrated by tests 5 to 8 below, in which the concentrates are:

Concentrate A: emulsion for ordinary cutting oil - used at a dose of 2 to 3% V / V (by volume)

Concentrate B: ordinary cutting oil - used at a dose of 1 to 4% V / V Concentrate C: rolling oil for aluminum which decomposes on

pinching of the cylinders and then regenerates - used at a dose of 5% V / V

20 Concentrate D: semi-synthetic formulation for cutting oil

- used as cutting oil at a dose of 1 to 2% V / V Concentrate E: ordinary cutting oil - used at a dose of 3 to 5% V / V

Concentrate F: cutting oil for high-grade finisher - used 25 at a dose of 3% V / V

, Concentrate G: aqueous, oil-free sharpening fluid - used per dose

2 ° / o V / V

Test 5 - Emulsion stability

Cutting and woolening oils used in the form of O / W emulsions must maintain their emulsion stability during use. This test checks the stability of these emulsions by / noting the tendency of the oil droplets to come together, which is / an indication of instability. / l // "

AT

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O / W emulsions containing commercial concentrates are prepared according to the following technique / standardized test (IP) 263/70 of the British Petroleum Institute /:

The concentrate and distilled water are brought separately to 20-4 ° C. The appropriate volume of water is stirred in a 500 cm 3 conical flask, with a magnetic stirrer, at a speed sufficient to form a vortex just deep enough to reach the bottom of the flask. Using a hypodermic syringe without needle, the appropriate volume of concentrate is quickly added and then the appropriate volumes of aqueous solution at 5000 ppm of dimetridazole, metro-nidazole or ipronidazole to obtain contents of 50,100, SJ0 and 500 ppm in emulsion (total volume 200 cm3), and stirred further for 2 minutes. Control emulsions without dimetridazole, metronidazole or ipronidazole are prepared in the same way.

The emulsions are then left to stand at room temperature for 24 hours.

A sample of the emulsion is then diluted to 1/2000 with SteriflexNo 1 Saline solution (Allen and Hanbury Ltd) and the dimensional distribution of the "large" oil droplets is determined in a 0.5 cm3 sample of this dilution using a Coulter counter (Coulter Electronics Ltd) with orifice of 100 μm connected to a P 64 recording analyzer. The emulsions are still left for 7 days and the dimensional distribution is again determined. oil droplets using the same r 25 Coulter meter setup to allow direct comparisons.

As is normal with O / W emulsions which have remained at rest for several days, a separation between oil, coagulate and cream is observed between the two determinations. Before taking the sample for the second determination, the vials are shaken / 30 for 30 seconds, rotating alternately to the right and / to the left. / J /? 16

The following results are obtained:

(a) O / W emulsion at 2% V / V of concentrate A

Metronidazole: an increase in droplets of 2-5yfym3 per 100 ppm of metronidazole at 7 days indicates very slight instability

Dimetridazole: 7-day stability increased slightly, especially at 50 ppm dimetridazole

Ipronidazole: no significant decrease in stability at 7 days a

(b) O / W emulsion at 1% V / V of concentrate B

10 Metronidazole: slightly improved 7-day stability

Dimetridazole: slight instability at 7 days for 250 ppm Ipronidazole: no significant change in stability at 7 days

(c) O / W emulsion at 3% V / V of concentrate F

15 Metronidazole: no change at 7 days

Dimetridazole: no change at 7 days

(d) O / W emulsion at 3% V / V of concentrate B

Metronidazole: slight improvement in stability at 7 days Dimetridazole: stability at 7 days is within satisfactory limits

Ipronidazole: very slight decrease in stability at 7 days (e) O / W emulsion at 1% V / V of concentrate D Metronidazole: no change at 7 days

Dimetridazole: slight improvement in stability at 7 days 25 Ipronidazole: very slight decrease in stability at 7 days in the O / W emulsion containing 250 ppm dipriprididole

(f) O / W emulsion at 2% V / V of concentrate G

Ipronidazole: no significant change at 7 days (g) ulsion / B emulsion at 2% V / V of concentrate C.

30 Metronidazole: unchanged,

Dimetridazole: unchanged /] /

Ipronidazole: very slight drop in stability at 7 days / 1M

4 17

These results show that the incorporation of dimetridazole, metronidazole or ipronidazole at concentrations of 50,100,250 and 500 ppm in O / W emulsions has no significant negative action on emulsion stability.

5 Test 6 - Corrosion

This test checks the ability of O / W amulsions to prevent rusting of machines and products during machining operations, according to the following technique (IP 287/74).

Melt chips are washed with pure acetone without touching them by hand, and dried in an oven at 48 ° C. Once dry, the chips are passed through a 25 mesh English sieve (0.67 mm opening, roughly equivalent to the AFNOR module 29 sieve), rejecting the fines.

A 35 mm square is drawn in pencil in the center of a filter paper (Whatman No 5? Qualitative, 90 mm) which is placed at the bottom of a Petri dish. Using a spatula and a template, the square is covered with a single layer of shavings. The template is removed and pipettes of the 2 cm 3 doses of emulsions (prepared as in test 5) containing a range of concentrate contents are pipetted so that the entire surface of the dish is covered and the shavings are well wetted. The lid is then placed on the box. After 2 hours the filter paper is removed, washed with tap water and allowed to dry. We place a transparent grid on the square, we appreciate the stained surface and we express it in%. To facilitate 25 the estimate / rusted area should occupy 10 to 60% of the square. This determines the critical dilution at which a significant increase in the stained area appears. For each concentrate, a series of O / W emulsions are prepared at the critical dilution and containing 50,100,250 or 5OO ppm of metronidazole, dimetridazole or ipronidazole 30 and these emulsions are subjected to the same test. The results are as follows: /? / * F & 18

(a) H / B emulsion at 2.5% concentrate A

„... Stained area%

Concentration in - ..... - - - - nitroimidazole (ppm) Metronidazole Dimetridazole 0 (control) 8 2 5 50 10 4 100 10 6 250 i 8 10 500 | 0 10

There is a slight decrease in the stained area for 250 ppm and 500 ppm of metronidazole. Repeated tests confirm this 3-5 observation. Slight increase in the area stained with dimetridazole.

(b) O / W emulsion at 4% V / V of concentrate B

..Surface .stained%

Concentration in ..........— ’i '.............

20 nitroimidazole (ppm) Metronidazole Dimetridazole Ipronidazole 0 (control). 15 15 65 50 20 18 60 25 100 30 25 60 250 35 30 40 30 500 40, 40 50 s ^

'- W

i 19 4 f

There is a slight increase in the stained area with both metronidazole and dimetridazole, a slight decrease with ipronidazole.

(c) O / W emulsion at 5% V / V of concentrate C

_. - -

Stained area%; · Nitroimidazole concentration (ppm) Metronidazole Dimetridazole 0 (control) 50 20 10 --- 50 60 20 100 50 20 15 25Ο 70 40 »500 70 50

A slight increase in the stained area is observed both for metronidazole and for dimetridazole.

(d) O / W emulsion at 2% V / V of concentrate D

Stained area%

Concentration in 1 _ nitroimidazole (ppm) Metronidazole Dimetridazole Ipronidazole 25 0 (control) 40 35 3 ° 50 40 40 25 100 40 50 55 250 40 50 30 500 4o 4o 15 / - -L - ^ - 1 —— y 20 *

There is no change with metronidazole but a slight increase in rust with dimetridazole; with ipronidazole there is a slight increase at 100 ppm and a slight decrease at 50,250 and 500 ppm.

5 (e) ulsion / E emulsion at 3% V / V of concentrate F

Stained area%

Nitroimidazole concentration (ppm) Metronidazole Dimetridazole jq O (control) 40 45 50 60 20 loo 30 45 250 30 30 500 30 25 ___ 15 There is a slight variation with metronidazole and dimetri dazole.

(f) O / W emulsion at 5% V / V of concentrate E

Λ,. Stained area% '

Nitroimidazole concentration (ppm) Metronidazole Dimetridazole 20 ----- = 0 (control) 25 20 I MM · * ·· - · I I 1 - 50 30 25 100 25 30 250 20 35 25 500 20 45

• K

"* 21

These results show that at the concentrations tested, neither metronidazole nor dimetridazole significantly interfere with the anti-corrosion properties of the emulsions.

(g) O / W emulsion at 2% V / V of Q concentrate

5 _ ... Stained area%

Nitroimidazole concentration (ppm) Ipronidazole 0 (control) 15 50 3 100 3 10 250 3 500 3

There is a slight decrease in the stained area.

Test 7 - Action on pH

O / W emulsions are prepared as indicated in test 5 and 15, the pH is measured on days 1 and 7 after the preparation, using a pH meter equipped with an Ingold electrode. The following results are obtained: (a) 2.5% V / V emulsion of concentrate A.

pH

Metronidazole concentration Dimetridazole Ipronidazole 20 ______ nitroimidazole fppm) Day t Day? Day, Day? Day ·, Day y 0 (witness) 8.8 8.6 8.9 8.8 9 * 76 9 * 21 50 8.8 8.7 8.9 8.8 9.97 9.83 100 9.0 8.6 8.9 8.8 9.76 9.30 25 250 8.9 8.6 8.8 8.8 9.88 9.50 / -------- 7/500 8.8 8.6 8.8 8.8 9.95 9 »81 / | ^ 22

(b) 4% V / V emulsion of concentrate B

PH

Concentration in ~ 'Π ~ ~ i TT!

Metronidazole Dimetridazole Ipronidazole nitroimidazole (ppm) ---- day 1 day 7 day 1 day 7 day 1 day 7 0 (control) 9.4 9.0 9.2 9.0 9.78 8.89 5 50 9.2 9.0 9.2 9.0 9.81 9.17 100 9.2 9.2 8.9 9.2 9.0 9.89 9.20 250 9.2 9.0 9.2 9.0 10.10 9.35 500 9.2 9.0 9.2 9.0 9.94 9.26

(c) 5% V / V emulsion of concentrate C

10 pH

Metronidazole concentration Dimetridazole Ipronidazole nitroimidazole (ppm). „. .. ..

day 1 day 7 day 1 day 7 day 1 day 7 0 (witness) 8.2 8.0 8.2 8.0 8.40 8.46 50 8.2 8.0 8.2 8.1 8.43 8.53 15 100 8.1 8.0 8.2 8.0 8.41 8.50 250. 8.2 8.1 8.2 8.0 8.43 8.50: 500 8.2 8.0 8.2 8.0 8.68 8.81 ^

UC

* 23

(d) 2% V / V emulsion of concentrate D

pH

Concentration in 1 .......— 1 -.,. ntv Metronidazole Dimetridazole Xpronidazole nitroimidazole (ppm) _ * _ day 1 day 7 day 1 day 7 day 1 day 7 5 0 (control 9.4 9.2 9.4 9.2 9.63 9.00 50 9.4 9 , 2 9.3 9.2 9.72 9.10 100 9.4 9.4 9.4 9.4 9.2 9.69 9.18 250 9.4 9.2 9.4 9.2 9.2.85 9 .26,500 9.4 9.2 9.4 9.2 9.81 9.14

10 (e) 5% V / V emulsion of concentrate E

pH

Metronidazole concentration Dimetridazole Ipronidazole nitroimidazole (ppm). .. _. „. „. ..

day 1 day 7 day 1 day 7 day 1 day 7 0 (witness) 9.5 9.2 9.4 9.2 9.94. 9.53 • 15 50 9.4 9.2 9.4 9.3 10.01 9.60 100 9.4 9.4 9.2 9.4 9.2 9.98 9.60 250 9.4 9.2 9.5 9.3 9.98 9.54 500 9.5 9.3 9.5 9.3 10.02 9.60 ^ »24

(f) 3.5% V / V emulsion of F concentrate

PH_

Metronidazole concentration Dimetridazole nitroimidazole (ppm) “" * _________———— r— - - day 1 day 7 day 1 day 7 0 (control) 9.1 9.0 9.0 8.9 5 50 9.0 8 .9 9.1 8.9 100 9.1 8.9 9.1 9.0 250 9.1 9.0 9.0 8.9 500 9.1 9.0 9.0 9.0

(g) 2% V / V emulsion of concentrate G

10 pH

Concentration in Ipronidazole nitroimidazole (ppm) '1 ----- day 1 day 7 0 (control) 10.01 9.06 50 10.18 9.54 15 100 10.12 9.48 250' 10.12 9, 56,500 10.16 9.56

These results show that at the concentrations tested neither metronidazole nor dimetridazole nor ipronidazole affect the pH of the emulsions in significant proportions. / 1 /

NOT

25 *

Test 8 - Foaming characteristics

This test (IP 312/74) makes it possible to determine the foaming characteristics of the emulsions, according to the following technique:

Η / E emulsions are prepared according to the method of test 5 5 but by replacing the distilled water with synthetic hard water / calcium sulphate solution of total hardness equivalent to 200 -10 ppm of calcium carbonate, prepared by dissolving 0.344 g S0 ^ Ca32H20 in 1 liter of distilled water /.

100 cm3 of emulsion are poured into a 10 250 cm3 graduated cylinder, the mixture is capped and stirred vigorously for 15 seconds.

Then place the test piece vertically and note the total volume (foam and liquid) immediately and after 1.5, 10 and 15 minutes.

Foam can also form on top of the foam but this foam tends to burst leaving air pockets and it is difficult to assess the height of the foam. The foam, being denser, can be seen better and, for convenience, the level of foam is noted.

With concentrate C, dilution with synthetic hard water produced a precipitate, which was not altered by the addition of metronidazole, dimetridazole or ipronidazole. The test was repeated by diluting the concentrate C with distilled water, and it is the results concerning this dilution which are reported below.

The results are as follows:

(a) 1% V / V emulsion of concentrate B

Volume concentration - total after & - rest (minutes) __ metronazole (ppm) 0 1 5 10 15 0 25. (witness) 120 100 100__100__100 50 120 101 100 100 100 100 120 100 100 100 100 250 120 100 100 100 100/30 500 125 101 100 100 100 * 26

Concentration in total volume after rest (minutes) dimetridazole (ppm) 0 1 5 10 15 'ô: (control) 150 100 100 100 100 50 120 100 100 100 100 5 100 120 100 100 100 100 250 130 100 100 100 100 500 150 150 100 100 100 100

Total volume concentration after rest (minutes) ipronidazole - "_ (ppm) '01 5 10 15, 0.

10 (temoxn) 202 174 152 142 131 —------: - 50 182 176 164. 132 .130 100 194 182 154 138 134 250 198 188 158 134 132 500198 I84 154 141 131

15 ^ k) Emulsion at Î% V / V fle concentrated D

Total Volume Concentration after rest (minutes) metronidazole (ppm) ~ [d ~ ^ ^ 0

(witness). > 2501> 250 [250 I 150; 140 I

50> 250> 250 25Ο I4O 125 20 100> 250> 250 235 150 135

25Ο> 250> 25025Ο I4O I3O

155> 250> 250 250 145 130 v, / '' Ψ * 27

Concentration in Total volume after rest (minutes) dimetridazole (ppm) --- = ----- __0__1__5 10__15 0 (control)> -250> 250 250 1A0__125 • 5 °> 250> 250 250 150 150 5 100> 2p0> 250 24Ο 155 120 - L ..- I -------- ---------- '....... "' 250> 250> 250 250 150 155 500> 250> 250 250 145 125 (! L ^ 250 ”s = foam level above the line 250 cm3) Concentration in total volume after rest (minutes)

Ipronidazole (? Pm) '' "! 10 0 1 5 10 15 0 (witness) 190 190 188 146 132 50 193 188 146 138 130 '' ........ iv, jw 100 206 204 126 124 122 250__192 17 o__1o2 140 130 15 500 212 190 140 128 120 --J ----- * fr 28

fc) 3% V / V emulsion of F concentrate

Concentration in Total volume after rest (minutes) metronidaaole (ppm) “! J ~ ~ ~ 0 (control) 150 108 105 104 104 50 145 110 108 106 106 5 100 150 112 108 106 104 250 140 108 106 104 104 5 °° 160 108 104 104 102

Total Volume Concentration after rest (minutes) imttridazole (ppm) - ^^ ----——-; - ~ - 0 10. (witness) 145 106 104 104 102 50 140 108 106 104 104 100 150 108 108 .106 104 250 ’145 110 106 104 104 500 160 108 104 104 102 / * f 29

(d) Emulsion at 3% V / V of concentrate E

Concentration in t Total volume after standing (minutes) metronidazole (ppm) -q— 3d ^ ^ ^ 0 (control)> 250> 250 220 170__15 * 0

50> 25Q> 250 25Ο I70__ISO

100> 250> 250 250 150 140_

5 25Ο> 250> 250> 250 160 HO

5OO> 250 | > 250 24Ο 180 140 __... - ------- 1—- ---- -----. -

Concentration in 4 Total volume after rest (minutes)

aimeiridazoie (ppm) Γ ~ I

'0 1 5 10 15 0 (witness)> 250> 250 210 140 140 50> 250> 250 220 170 15Ο 10 1 ° 0> 250> 250 210 180 160 25Ο> 250> 250 24Ο 180 160 5 °°> 250> 250 220 170 150

Concentration in (·

Ipronidazole Total volume after rest (minutes) (ppm) '~~ --------------- __0___1 5 10 15 0 15 (control) 168 108 102 102 100 50 172 122' 110 '104 102 _100__168 118 108 104 102 250__166 _120__108 106 102 ^ 500 192 114 106 104 102/9 / i 1 / //

(β) 2% V / V emulsion of concentrate A

♦ 30 1 ...... 1 '............ I. ----------. -. ----—,. . ... - --------_ - ----- _ ------------ "

Concentration in ^ Total volume after rest (minutes) metronidazole (ppm) ~! ~ ^ 1Q ^. · '0 (witness) 140 IO5 101 100 100 —-------'-- ï 50 I50 106 104 101__100 100 140 104 102 100__100 250 155: 106 104 101 100 500 | 140 106 105 104 102

Total volume concentration after rest (minutes) dimetridasole (ppm) ”T ~ ^ * j“ ~ ~ 0 10 (control) 155 103 101 101 101.

50 150 110 101 101 100 100 155 112 102 100 100 ____________—---- 250 130 101 101 100 100 500 140 104 101 100 100

Concentration in

15 Ipronidazole Total volume after rest ^ minutes) I

(ppm): -—-—----- __0 1 5 10 15 0 (control) 246 122 114 110 106 _50_ 23Ο 116 114 110 102 _100_ 212 HO 128 118 114 20 250 _ 202 128 112 110 10é / 500> 250 116 108 104 100 / '/ y *

(f) 3% V / V emulsion of concentrate C

31

Concentration in Total volume after rest _ (minutes) metronidazole (ppm) Ö r ~ 1 5 I ÏO 15 0 101 100 100 100 100, (control) _______________ 100 100 100 100 100 5 50_____________ 100 -joO 100 100__100__100 250 -jOO 100 100 100 100 _ 100 100 100 100 100

Concentration in ^ Total volume after rest (minutes) dimetridazole (ppm) "~~ ZTI l ~“ “i '“ • 0 1 5 10 15 10 ----—---------- °., 102 100 100 100 100 (witness) 50 100 100 100 100 100 100 "loo 100 100 1 00 100 25 ° 100 100 100 I 100 100 15 5 °° _ 100 100 100 | 100 100

Concentration in

Ipronidazole Total volume after rest - (minutes) ^ ppm ^ 0 1 1 5 10 15 0.

. (witness) 152 132 116 110 108 50 142 112 108 106 104 "J - -? n ___ 100__13§ 110 106 104 102 t -" ‘250__I42__112 '108 104 102 500 152 114 110 108 104' S,

(g) 2% V / V emulsion of concentrate G

* 32 '"" 1 ———... _. .......

Total volume concentration after rest (minutes)

Ipronidazole --------_----- (wm) ___ 0 1 1__5 10 15 '(ttocin) | 100 d 100 100 100: 100 50 100 100 100 100 100 5 100 _ 100 100 100 100 100 230_ 100 100 100 100 100 500 100 100 100 100 100

. These results show that the addition of metronidazole, dimetridazole or ipronidazole at the concentrations indicated does not cause any significant differences in the foaming of the emulsions / studied. / J

r \ t r 33 The following example illustrates a concentrate which makes it possible, after suitable dilution with water, to obtain a machining liquid according to the invention.

EXAMPLE

5 A suspension is prepared by mixing:, Dimetridazole microfin 25% w / v Iexofor M6 4% ”

Arylan CA 6% n

Attagel 50 1% "10 Deodorized kerosene q.s.p. 100% by volume

1 liter of this concentrate is mixed with 99 liters of concentrate for ordinary cutting oil and 100 liters of concentrate containing 2,500 ppm of dimetridazole are obtained. Diluting these 100 liters of • 15 concentrate in 2,400 liters of water gives 2,500 liters of liquid / machining containing 100 ppm of dimetridazole. /

Claims (14)

34 H »EJN V E N D I C A_T IONS 1. A method of combating the deterioration of technical liquids, either organic and containing water, or aqueous and containing organic matter, by strict anaerobic sulfatoreductive bacteria, characterized in that at least one incorporated in the aqueous phase derivative 5 of nitroimidazole chosen from dimetridazole, metronidazole, secnidazole and ipronidazole in an amount sufficient to prevent the growth of said bacteria. 2, - A method according to claim 1 characterized in that the technical liquid is a petroleum or vegetable oil containing water, or an aqueous liquid containing a petroleum or vegetable oil. 3. Method according to claim 1 or 2, characterized in that the technical liquid is a combustible or lubricating oil, a hydraulic fluid based on mineral oil, an O / W or W / O emulsion, an aqueous solution or emulsion of glycols for machining liquid, waste water from sulphite pulp, water-based paint, injection water for oil drilling, waste water, electroplating solution, cooling circuit , a hot water storage and distribution system or a gasometer water seal. 4 - Process according to claim 3, characterized in that the U / E emulsion is a machining liquid. 5. Method according to claim 3, characterized in that the W / O emulsion is a hydraulic fluid. 6. Method according to one of claims 1 to 5, characterized in that, in an organic liquid containing water or in an aqueous liquid containing organic material, a solution, suspension or emulsion is added comprising at least a nitroimidazole chosen from dimetridazole, metronidazole, secnidazole and ipronidazole and water, glycols, ethyl oxalate, dimethylformamide, dimethylacetamide, liquid hydrocarbons or their mixtures and, if necessary, at least one surfactant. / Λ * / ^ * 35 7. Method according to one of claims 1 to 6, characterized in that 100 to 500 ppm of nitroimidazole derivatives are incorporated, relative to the total volume of the technical liquid, into the aqueous phase of said liquid. 8. Method according to one of claims 1 to 6, characterized in that incorporates into the aqueous phase of the technical liquid 100 ppm, relative to the total volume of the technical liquid, nitroimidazole derivatives. 9. Method according to one of claims 1 to 8, characterized in that the derivatives of nitroimidazole are used in combination with one or more agents known for combating the alteration of said technical liquids. 10. The method of claim 9, characterized in that the known agents are chosen from p-chloro m-cresol, phenol, compound of heavy metals and formaldehyde generators. 11. Method according to one of claims 1 to 10, characterized in that the strict anaerobic sulfatoreductive bacteria are Desulfovibrio desulfuricans, Desulfovibrio gigas and / or Desulfotoma-culum nigrificans. 20 '12 - Method according to one of claims 1 to 11, characterized in that the nitroimidazole used is dimetridazole. 13. Method according to one of claims 1 to 11, characterized in that the nitroimidazole used is metronidazole. ir * 1 ^ - Concentrate for obtaining a working liquid by appropriate dilution with water, comprising oils and / or glycols, emulsifiers and usual corrosion inhibitors, characterized in that it contains at least one derivative of nitroimidazole chosen from dimetridazole, metronidazole, secnidazole and ipronidazole, in an amount sufficient to give in the working liquid after dilution with water a concentration of derivative of nitroimidazole, which inhibits the growth of anaerobic bacteria strict / \ / sulfatoréductrices. / Λτ r% 36 15. Concentrate for machining liquid according to claim 14, characterized in that it contains from 0.05 to 5% w / v of nitroimidazole derivative. 16. Concentrate according to one of claims 14 or 15, characterized in that the nitroimidazole is dimetridazole. • * 7 - Concentrate according to one of claims 14 or 15 5 characterized in that the nitroimidazole is metronidazole. Drawings: ........ plates ......... 2x & - pages of which ....... Λ ........ cover page „... jLä .. .... pages of description .......... to .... pages of claims ______ ô ~~~ short description Luxembourg, AUGUST 2 0 1982 Le m ^^^ taire: ^ - ^ Charles München Λ