GB2115311A

GB2115311A - Composition for the dispersion of hydrocarbons in water

Info

Publication number: GB2115311A
Application number: GB08305191A
Authority: GB
Inventors: Guy Vanlerbergue; Henri Sebag
Original assignee: Societe National Elf Aquitaine; LOreal SA
Current assignee: Societe National Elf Aquitaine; LOreal SA
Priority date: 1982-02-26
Filing date: 1983-02-24
Publication date: 1983-09-07
Also published as: FR2522280B1; GB2115311B; GB8305191D0; FR2522280A1; NL8300676A; CA1190451A

Abstract

Compositions for the dispersion of hydrocarbons in water, comprise a mixture of at least one surfactant R-O-[-C2H3O(T)-]-nH where R is a hydrocarbon group and T is another group carrying at least one OH, with an organic solvent and/or with water. The compositions can be used for the dispersion of hydrocarbons, e.g. crude oil, from the surfaces of water, rocks or beaches or from receptacles after containing petroleum, if desired after dilution with seawater.

Description

SPECIFICATION Composition for the dispersion of hydrocarbons in water The invention relates to a new type of composition based on surfactants, for the dispersion of hydrocarbons in water; it relates more particularly to dispersion in sea-water.

The dispersion of hydrocarbons in water has become a very frequent and important operation at the present time. In an age where petroleum and its derivatives are of extremely widespread usage, it is more and more often necessary to clean surfaces or receptacles after containing such products; the well-known method utilised for this purpose consists in treating the soiled surfaces with an aqueous solution of one or more surfactant compounds capable of producing dispersion of the hydrocarbons in the aqueous phase; the fluid emulsion so obtained can then be readily disposed of; the hydrocarbons can also be recovered after separation of their dispersion into two layers.At the present time, numerous anionic, cationic and nonionic surface-active agents are known which are satisfactory; however, as these cleaning operations are generally repeated quite often in factories or in public places, the toxicity of the surface-active compounds must be taken into consideration. Most known emulsifiers have a more or less marked toxicity, particularly as regards lower animals. One use of dispersant compositions, which has become extremely important during the last decade, is action against the spillage of a hydrocarbon layer on an aqueous surface, particularly at sea, derived from the transport of petroleum, namely the so-called "black tide" accident. The procedure most often employed in this case consists in spraying a surfactant composition on to the oily layer, with a view to dispersing the hydrocarbon in the underlying water.However, when this operation takes place at sea or on an area of fresh water, the toxicity of the surface-active agent utilized can constitute a danger, for the fauna and flora present, which is just as great as the hydrocarbon itself. As mentioned above, most surfactants utilized at present are more or less toxic and their use represents a real disadvantage from the ecological standpoint. Also, homologation criteria impose on compositions utilized at sea a tolerance limit, for the CL50 lethal concentration at 96 hours, of 200 mg/l; it is not easy to abide by this condition when the dispersants contain anionic surfactants. Also, various products utilized as dispersants at present contain esters, which have the major disadvantage of being unstable in storage, either because they hydrolyse or because they can undergo transesterification reactions.

The present invention relates to the utilization of essentially nonionic surfactants of the polyether polyol type as hydrocarbon dispersant agents, having a low toxicity to lower animals and being stable in aqueous or alcoholic media. Such nonionic surfactant compounds of the polyether polyol type, containing hydroxypropylene groups, have already been utilized in cosmetics, as indicated i.a. in French Patents 1477048 and 7621961.

The present invention relates to the preparation of specific compositions which enable the rapid production of a hydrocarbon dispersion which is stable for a sufficiently long time as required for the intended purpose.

The new compositions according to the invention, constituted by a mixture of at least one surfactant with an organic solvent and/or with water, are charcterised in that the mixture contains 20% to 80% by weight of a surfactant corresponding to the formula: RO [ C2H 30(T) ] nH (1) wherein R is a hydrocarbon group which can carry substituents, particularly OH, T is a group or chain carrying at least one hydroxyl group and n is a number from 1 to 30, the amount by weight of solvent constituting 0% to 80% and preferably 5% to 60% of the mixture and that of the water comprising 0% to 60%.

In a particular embodiment of the invention, the surfactant (1) is a glyceryl polyether, in which R is a straight or branched, saturated or unsaturated, C5 to C22 alkyl or hydroxyalkyl group, optionally carrying one or more aryl groups; n has a value from 1 to 10 and T designates -CH2OH. Purely by way of illustrative example, such a compound can be oleylhexaglyceryl ether:

in which some or all of the glyceryl groups can be in the isomeric form

According to another advantageous embodiment of the invention, the surfactant is a polyether of formula (1), in which R is a straight or branched aliphatic or cycloaliphatic group having 4 to 30 carbon atoms; n is an integral or fractional number from 1 to 25;T comprises a group A and at least one group CH2XR', wherein R' is a C5 to C20 alkyl group, X is -CH2-, -O-, -S- or = SO, while A can be CH20H, CH2 SCH2CH20H,

CH2SCH2CHOHCH2OH or

Preferably, the proportion of A groups is at least 50%.

In a particular embodiment of the invention in which R in the formula (1) represents a straight or branched, saturated or unsaturated aliphatic, cycloaliphatic, aromatic or alkylaromatic hydrocarbon group comprising 1 to 30 carbon atoms, n can have an average statistical value of 1 to 20, while T is a group A such as: -CH20H, -SCH2CH2OH,

-SCH2CHOHCH2OH or

and/or at least one group: R11O(C2H3(A)O ] rnCH2 wherein R" is a hydrocarbon group having 8 to 30 carbon atoms and m has an average statistical value of 0.5 to 10.

The solvents contained in the compositions according to the invention are preferably selected from organic compounds having some affinity with water, particularly compounds at least very slightly soluble in water. In particular, these are substances having at least 4 carbon atoms in the molecule, in particular alcohols, glycols, ether alcohols, diethylene and dipropylene glycol ethers, etc. Among preferred solvents, reference can be made to C4 to C8 alcohols, straight or branched, particularly butanols, hexanols and 2-ethyl-hexanol; among glycols, the preferred ones are butylene glycol and hexylene glycol; as ether alcohols, reference can be made to 2butoxyethanol, 2-hexyloxy-ethanol, butyl diglycol or the butyl or isobutyl ether of dipropylene glycol.

The proportions mostly used are 30% to 60% of the surfactant and 30% to 60% of the solvent, the balance being water.

According to a particular feature of the invention, the stability and efficacy of the composition, for the dispersion of hydrocarbons, is augmented by the presence of an electrolyte in the water of the composition. As there is an optimum salinity corresponding to each surfactant, the concentration of electrolyte in the water of the composition varies with the nature of this agent; in particular, it can range from 0.01 to 5 moles of salt per litre of water and more particularly from 0.1 to 2 moles/l. The salt or salts thus present in a composition according to the invention are water-soluble salts of the alkali metals or alkaline earth metals of inorganic or organic anions; use can be made for example of the chlorides, sulphates, sulphites, acetates, tartrates etc. of sodium, potassium, calcium, magnesium or zinc. These examples are the salts of greatest interest economically, but it is to be understood that other compounds of the same type equally can be employed.

A practical means for the preparation of a composition according to the invention consists in employing sea-water, diluted with fresh water, if required.

The surfactant most especially preferred corresponds to the formula (1) in which R = R3 = a mixture of C8H,7 to C10H2, radicals and n = 9, T in 2/3 of the units is the group CH20H and, in 1/3 of the units, the group R30- [ -C2H3(CH20H)O- ] -mCH2- where m = 0.5. The most recommendable solvents then are butyl diglycol and the isobutyl ether of dipropylene glycol.

The compositions defined above can, if necessary, also contain one or more anionic surfactants in concentrations such that the toxicity of the final composition remains within acceptable limits. Use can be made for this purpose of standard anionic surfactants known to the person skilled in the art, for example, the alkyl metal salts of alyl-sulphuric, alkyl-ether sulphuric, alkane-sulphonic and alkyl-aryl-sulphonic acids, sulphonic acids derived from alphaolefins, alkoxy-polyethoxy-methylene-carboxylic acids or anionic surfactants such as those described in French Patent Application 2430938 and Luxembourg Patent Application 82646.

The compositions can be utilized as such and dispersed from the air or by vessels equipped with spray systems of the Warren Spring Laboratory type of the like or by dispersant jets at the waterside, e.g. along coastal or lakeside locations and at port and harbour installations. In certain cases, they can be previously diluted with sea-water.

The invention comprises a process of dispersion of hydrocarbons spread on the surfaces of water, rocks, beaches or present in tanks or other receptacles after containing petroleum. This process consists in applying to petroleum slicks or inside soiled receptacles a composition such as defined above. In carrying out this process, use can equally be made of aqueous solutions solely containing the compounds of formula (1) in water.

In the non-limitative examples which follow, the dispersant efficacy of various surfactants defined above has been determined according to the Canadian standard SET (Simulated Environmental Tank), which consists in dispersing 100 g of hydrocarbon in 139 litres of water, which approximates to actual conditions of anti-pollution treatment of petroleum slicks on the sea. The tests were carried out with crude petroleum having a density of 0.881 at 20 C and a kinematic viscosity of 33.8 cst at the same temperature; the flowpoint of this hydrocarbon was + 94C. The proportion of the dispersant composition was 10 volumes per 100 volumes of petroleum.

EXAMPLE 1 The surfactant utilized is a mixture of compounds of formula (1) in which R designates the radical C12H25, T represents a mixture of C,2H25-O-CH2- and -CH20H radicals in the proportion of 5/15 and n = 20. The solvent employed is butyl-diglycol (B.D.G.), namely: C4H9OCH2CH2-O-CH2CH2OH The composition by weight percentage is: surfactant mixture 38.7% butyl-diglycol 39.0% mixture of sodium acetate and sodium chloride 2.8% water 19.5% After dispersion of the petroleum in sea-water with this composition, the emulsion was left to stand for 10 minutes and it was determined that 82% of the petroleum remained in the dispersed state. This proportion was still 64% after 1 hour and 54% after 2 hours, equivalent to the result obtained with the best commercial products.However, the latter are more or less toxic, while the composition of the present example has a CL50 lethal concentration at 96 hours of 350 mg/l relative to the grey shrimp.

EXAMPLES 2 to 12 The Table below gives the results of tests with other compositions according to the invention; it indicates the nature of the groups R and T in the surface-active compounds according to formula (1), as well as the numbers n in this formula.

For the solvents and the mixtures employed, the following abbreviations are used: TA surfactant B.D.G. butyl-diglycol l.D.P.G. isobutyl ether of dipropylene glycol "A" .. mixture in % of 50.0 T.A.

48.5 B.D.G.

1.5 salts "B" .. mixture in % of: 38.0 T.A.

39.0 B.D.G.

20.6 water 2.4 salts "C" .. mixture in % of: 9.9 T.A.

54.7 B.D.G.

31.45 water 3.95 salt RESULTS OF EXAMPLES 2 - 10

Exam- COMPOSITION Efficacy ple N R T n Nature % 10' 2 C12H25 -C10H21/-CH2OH 5/15 20 T.A. 40 B.D.G. 40 64% Water 20 3 C16H33 -C14H29/-CH2OH 4/20 24 T.A. 60 B.D.G. 20 45% Water 20 4 C12H25 R'-O#CH2-CH-O#CH2/CH2OH 3/7 10 "A" 100 86% # CH2OH 0,5 R' éthant-C12H25 "A" 80 59% I.D.P.G. 20 5 oléoCétyle -CH2OH 6 T.A. 60 I.D.P.G. 20 35% Water 20 6 C8H17/C10H21 R'-O#CH2CH-O#CH2-/CH2OH 1/2 9 "B" 100 72% # 0,5 CH2OH R' = mixture of radicals C18H17/C10H21 7 " " " 9 "B" 90 80% I.D.P.G. 10 8 C8H17/C10H21 " " 9 "B" 70 55% I.D.P.G. 30 9 " " " 9 "B" 70 72% Water 30 10 " " " 9 "B" 60 52% Water 40 RESULTS OF EXAMPLES 11 AND 12

Exam- COMPOSITION Efficacy ple N R T n Nature % 10' 11 C8H17/C10H21 R'-O#CH2-CH-O-#/CH2OH:1/2 9 "B" 34# # 0,5 # CH2OH # # 50% R' : C8H17/C10H21 # C12H25 CH2OH 4 "C" 66# 12 "B" 32,2# "C" 6,3# Sodium dodecyl # benzene sul- # phonate 5 # 70% B.D.G. 34,2# Salts 2,4# Water 19,5#

Claims

1. A composition comprising a mixture of at least one surfactant with either or both of an organic solvent and water, for use in the disperson of hydrocarbons in water, in which the mixture contains, by weight, 20% to 80% of a surfactant of the formula: R-O-C-C,H,O(T)-I-H, wherein R is a hydrocarbon group, optionally carrying one or more substituents, T is a group or chain carrying at least one hydroxyl group and n is a number from 1 to 30, and in which the solvent comprises 0% to 80% and the water comprises 0% to 60% by weight of the mixture.

2. A composition according to claim 1, in which the solvent comprises 5% to 60% by weight of the mixture.

3. A composition according to claim 1 or 2, in which the surfactant is a glyceryl polyether in which R is a straight or branched, saturated or unsaturated C8 to C22 alkyl or hydroxyalkyl group, optionally carrying one or more aryl groups, n is a number from 1 to 10 and T is a -CH2OH group.

4. A composition according to claim 1 or 2, in which the surfactant is a polyether in which R is a straight or branched, aliphatic or cycloaliphatic group containing 4 to 30 carbon atoms, n is an integral or fractional number from 1 to 25 and T comprises a group A and at least one group CH2XR', where R' is a C5 to C20 alykl group and X is -CH-, -O-, -S- or = SO and where A is -CH2OH, -CH2SCH2CH2OH,

-CH2SCH2CHOHCH2OH or

and the proportion of A groups in T is at least 50%.

5. A composition according to claim 1 or 2, in which in the surfactant R is a straight or branched, saturated or unsaturated, aliphatic, cycloaliphatic, aromatic or alkyl-aromatic hydrocarbon group comprising 1 to 30 carbon atoms, n has an average statistical value of 1 to 20 and T is a group A and/or at least one group R"O [ C2H3(A)O ] m-CH2 where R" is a hydrocarbon group having 8 to 30 carbon atoms and m has an average statistical value of 0.5 to 10 and where A is -CH2OH, -SCH2CH2OH,

-SCH2CHOHCH2OH or

6. A composition according to any preceding claim, in which the solvent is selected from C4 to C8 straight or branched alcohols, glycols and ether alcohols.

7. A composition according to claim 6, in which the solvent is selected from butanols, hexanols, 2-ethyl-hexanol, butylene glycol, hexylene glycol, 2-butoxy-ethanol, 2-hexyloxy-ethanol, butyl diglycol, the isobutyl ether of dipropylene glycol or the butyl ether of dipropylene glycol.

8. A composition according to any preceding claim, which contains, by weight, 30% to 60% of a nonionic surfactant of the formula and 30% to 60% of solvent, the balance being water.

9. A composition according to any preceding claim, which also contains one or more anionic surfactants.

10. A composition according to claim 9, in which the one or more anionic surfactants is/are selected from alkali metal salts of alkyl-sulphuric, alkyl-ether-sulphuric, alkane-sulphonic, alkylaryl-sulphonic acids or alkoxy-polyethoxy-methylene-carboxylic acids and of sulphonic acids derived from alpha-olefins.

11. A composition according to any preceding claim, in which water is present and contains in solution one or more electrolytes in an amount of 0.01 to 5 moles per litre.

12. A composition according to claim 11, in which the one or more electrolytes is/are selected from alkali metal and alkaline earth metal salts of inorganic or organic anions.

13. A composition according to claim 1, substantially as hereinbefore described.

14. A process of dispersion of hydrocarbons spread upon the surfaces of water, rocks, beaches or present in receptacles after containing petroleum, in which a composition according to any preceding claim is applied to petroleum slicks or in soiled receptacles.

15. A process according to claim 14, in which a composition according to any of claims 1 to 13 or an aqueous composition of a compound of the formula is first subjected to dilution with sea-water and is then used for hydrocarbon dispersal.