US3591524A

US3591524A - Oil absorbent

Info

Publication number: US3591524A
Application number: US778319A
Authority: US
Inventors: Knut Emil Eriksen
Original assignee: Mo och Domsjo AB
Current assignee: Mo och Domsjo AB
Priority date: 1967-11-29
Filing date: 1968-11-22
Publication date: 1971-07-06
Anticipated expiration: 1988-07-06
Also published as: DK127921B; DE1811023A1; NO118786B; NL6817041A; SE306981B; GB1221476A

Abstract

AN OIL ABSORBENT IS PROVIDED THAT IS CAPABLE OF PREFERENTIALLY ABSORBING OIL IN THE PRESENCE OF WATER, AND THAT WILL FLOAT ON WATER FOR A CONSIDERABLE PERIOD OF TIME WHEN LOADED WITH OIL, COMPRISING AN ABSORBENT CARRIER HAVING THEREON THE HYDROPHOBIC RESIDUE OF A HEAT-DECOMPOSED AMMONIUM OR AMINE SALT OF AN ALIPHATIC OR CYCLOALIPHATIC CARBOXYLIC ACID AND AN OIL.

Description

nited States Patent 3,591,524 01L ABSURBENT Knut Emil Eriksen, Enhorna, Sweden, assignor to M0 och Domsjo Aktiebolag, Ornskoldsvilr, Sweden No Drawing. Filed Nov. 22, 1968, Ser. No. 778,319 Claims priority, application Sweden, Nov. 29, 1967, 16,347/67 Int. Cl. Ctllb 1/14 US. Cl. 252-427 12 Claims ABSTRACT OF THE DISCLOSURE An oil absorbent is provided that is capable of preferentially absorbing oil in the presence of water, and that will float on water for a considerable period of time when loaded with oil, comprising an absorbent carrier having thereon the hydrophobic residue of a heat-decomposed ammonium or amine salt of an aliphatic or cycloaliphatic carboxylic acid and an oil.

This invention relates to an oilabsorbent, and to a method for preparing the same, that is capable of absorbing oils preferentially in the presence of water, and of floating on water when loaded with oil, and more particularly to an oil absorbent comprising an absorbent carrier having thereon a hydrophobic residue of a heatdecomposed ammonium or amine salt of an aliphatic or cycloaliphatic carboxylic acid, and an oil.

The recovery and disposal of petroleum that is spilled at sea, whether wilfully or accidentally, is rapidly becoming a very serious problem, that is encountered throughout the world. As the amounts of petroleum oil transported become larger and larger, in tankers of everincreasing size, the volumes of spilled oil become ever larger, and failure to control the spilled oil can lead to the contamination of miles of shoreline, with destructive damage to natural flora and fauna, as well as all types of man-made installations that are built into the water. Since the Torrey Canyon disaster, intensive efforts have been made to develop ways of controlling and disposing of the spilled oils.

Emulsifiers have been dumped in the sea, but these are so rapidly diluted by the sea currents that they are virtually ineffective. If indeed the spilled oil is emulsified initially in the surrounding water, the emulsion eventually is diluted to the point where the oil again precipitates, and the oil may in fact be transported only a short distance through the sea before this occurs.

It has been suggested that absorbent materials could be added which are heavier than Water, and which after the oil is absorbed, sink to the bottom and retain the oil at the bottom of the sea. These are not very satisfactory, however, because the oil is slowly liberated, and may cause damage to the flora and fauna at the sea bottom, besides polluting the water over great distances.

In addition to these difficulties, there is the problem, heretofore insurmountable, that the absorbent materials that have been employed are capable not only of absorbing oil, but also of absorbing water, and in fact in many cases they preferentially absorb water, with the result that only a small amount of oil is absorbed, when the oil phase is immediately adjacent to the water phase. These agents are therefore most effective when they are completely surrounded by oil. However, even if they absorb the oil initially, if they are preferentially wetted by water the water may displace the oil after the oil-loaded material sinks. Thus, the oil is usually only poorly bound to the absorbent, and is liberated slowly thereafter, if it is allowed to remain in the water. If the material sinks when loaded with oil, of course it can hardly be collected thereafter.

Patented July 6, 1971 Some absorbent materials that have been proposed have a highly porous structure of a capillary nature. These materials are capable of absorbing rather large amounts of liquids, due to capillary attraction. Such materials include peat, sawdust, cork, ground foamed plastic, shredded plastic, cellulosic materials, paper, bark, and ground or particulate cellulose. With the exception of hydrophobic plastics, however, all of these materials are hydrophilic, and preferentially absorb water. Moreover, all of them when loaded with oil and water tend to sink to the bottom, making recovery of the oil-loaded material impossible.

Petroleum oil tends to float, and if it can be destroyed in this condition, there is a minimum of damage to the flora and fauna of the sea. However, virtually the only way to destroy surface petroleum oil is by fire, and this is not only dangerous, particularly offshore, but it also can hardly be regarded as harmless to the sea fauna in the vicinity.

It would be highly desirable if a material could be provided that would make it possible to confine and collect the petroleum oil on the surface of the sea, and remove it by surface-skimming or surface-collection methods, for destruction on shore. Such techniques are not practical with the oil, so long as the oil is in a liquid condition. However, such materials have not been available.

In accordance with the invention, a free-flowing particulate oil absorbent is provided that is capable of absorbing oil preferentially in the presence of water, and that is also capable of floating on the surface of the water when the oil has been absorbed. Accordingly, the oilloaded absorbents of the invention can be collected on the surface of the water, and because the oil has been absorbed, and the materials are particulate solids, the collection is rather easy, and can be accomplished by relatively coarse sieves or filters. The collected material can be destroyed on shore, by burning, or can be used as a fuel.

The oil absorbent of the invention comprises a carrier of absorbent material that is capable of floating on water, and the carrier has absorbed thereon the heat-decomposed hydrophobic residue of an ammonium or amine salt of an aliphatic or cycloaliphatic carboxylic acid, and an oil.

The oil absorbent is prepared by impregnating an absorbent carrier with an emulsion of an oil in water, emulsified by an ammonium or amine salt of an aliphatic or cycloaliphatic carboxylic acid that can be decomposed by heating at an elevated temperature above 35 C. to form a hydrophobic residue in the presence of the oil.

The heating of the ammonium or amine salt of the carboxylic acid imparts a hydrophobic character to the carrier, after which it is water-repellent, so that water will not be absorbed to a significant degree. The ammonium or amine salt is thought to be decomposed in part, liberating ammonia or the amine and free carboxylic acid, and in part forming the amide. The free acid and the amide are each hydrophobic, and after the decomposition, the emulsifying properties are of course destroyed. The free acid may dissolve in the oil, while the ammonia or amine are volatilized with the water.

The amide and the carboxylic acid aid the spreading of the oil on the carrier, probably by decreasing the interfacial tension between the two phases. The carboxylic acid and amide groups, which are polar groups, aid in anchoring the oil to the carrier, by hydrogen bonding of polar groups to hydroxyl groups of the carrier, in the case of cellulosic and hydroxyl group containing resinous carriers. The result is that oil will be absorbed preferentially, even after long contact with and in the presence of water. The oil-loaded carrier is still sufficiently light to float on water, and because of its water-repellent property, the

3 floating characteristic is in fact enhanced, despite the added weight of the oil. The hydrophobic material is free-flowing, and it remains so in the presence of Water. However, when loaded with oil, it may form agglomerates, but these float as well as the nonagglomerated particles.

The carrier can be any light weight material having a density of less than water, and of a highly absorbent nature. Cellulosic material is particularly useful, and is preferred. Examples are sawdust, wood shavings, wood chips, cork, straw, cellulose pulp, cellulose flux shredded cellulose, cellulose linters, and bark, and paper, tissue paper, cardboard and hardboard, preferably in particulate form.

Also useful is sponge and foam material of various kinds, including regenerated cellulose sponge and resinous or plastic sponge, such as polyurethane, polyvinyl chloride, polyethylene, polypropylene, polystyrene, nylon, and vinyl chloride-vinyl acetate copolymer sponge and foam material. This material is preferably in particulate form, such as shredded, powdered, disintegrated, chopped, ground, and granular foam material. The preferred plastics are hydrophobic, but hydrophilic materials can be used.

The heat-decomposable ammonium or amine salt of an aliphatic or cycloaliphatic carboxylic acid is defined by the formula:

R is hydrogen or a saturated or unsaturated aliphatic or cycloaliphatic hydrocarbon radical having from one to about twenty-five carbon atoms.

R R and R can be the same or different, and are hydrogen or a saturated or unsaturated aliphatic hydrocarbon radical having from one to about twenty-two carbon atoms.

The R, R R and R radicals can, for example, be methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, amyl, isoamyl, hexyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, myristyl, palmityl, stearyl, oleyl, ricinoleyl, linoleyl, linolenyl, behenyl, allyl, hexenyl, nonenyl, and decenyl.

Thus, exemplary fatty acids include formic, acetic, propionic, butyric, valeric, capric, caprylic, caproic, lauric, myristic, palmitic, stearic, oleic, ricinoleic, linoleic and linolenic acids, as Well as the mixed fatty acids derived from tallow, coconut oil, linseed oil, cottonseed oil, corn oil, fish oil, tung oil, soyabean oil, and safilower oil, and

other vegetable and animal oils.

The natural resin acids obtained from pine Wood and other woods, including abietic acid, the naphthenic acids, and tall oil fatty acids, can also be employed.

The carboxylic acid salt can be an ammonium or amine salt. Any organic aliphatic amine can be used, including hydroxylamines, such as for instance, trimethylamine, triethylamine, tripropylamine, methyldiisopropylamine, tributylamine, triisopropylamine, trihexylamine, dihexylamine heptylamine, butylamine, propylamine, diisopropylamine, dibutylamine, tri(decyl)amine, di(decyl)amine, mon(decyl)amine, laurylamine, stearylamine, myristylamine, behenylamine, oleylamine, dioleylamine, trioleylamine, ricinoleylamine, linoleylamine, linolenylamine, tripalmitylamine, dilaurylamine, lauryldimethylamine, and dioctylamine. The amine is advantageously volatile at the decomposition temperature.

The ammonium and/or amine salt can be formed in situ, by reaction in aqueous solution of the acid and ammonia (ammonium hydroxide) or the amine.

The ammonium or amine salt is employed with an oil, which also aids in imparting a hydrophobic character to the heat-decomposed residue of the ammonium or amine salt. As the oil, there can be mentioned, as exemplary refined petroleum oils, such as No. 1 fuel oil, No. 2 fuel oil,

No. 3 fuel oil, No. 4 fuel oil and No. 5 fuel oil, bunker C-oil, wax oil, diesel oil, motor oil, machine oil, spindle oil, paraffinic hydrocarbons, such as octane, decane, nonane, dodecane, hexane and pentane; mineral oils, such as petroleum oil; vegetable oils, such as cottonseed oil, corn oil, linseed oil, soybean oil, tung oil, coconut oil, safflower oil, and sesame seed oil, and animal oils, such as mutton tallow and beef tallow, as well as fish oil, such as menhaden oil, tunafish oil, whale oil, and cod liver oil.

The oil is normally employed in a major proportion, and the ammonium or amine salt of the carboxylic acid in a minor proportion. Preferably, the composition includes from about 50 to about oil, and from about 50 to about 5 amine or ammonium salt of the carboxylic acid, added as the salt, or formed in situ. The ammonium or amine salt serves as an emulsifier for the oil, and consequently the amount is at least sufiicient to emulsify the oil in water.

The oil and ammonium or amine salt are dispersed or dissolved in water to form an emulsion of the oil in water. The amount of water is not critical, but of course the more water that is added to the absorbent carrier, the more water that must be removed by evaporation. Therefore, it is preferred to prepare a concentrated oil emulsion, containing at least 5% oil, and preferably from about 10 to about 40% oil, and from about 0.25 to about 20% salt.

The aqueous emulsion is readily prepared by first mixing the oil and the acid, and then adding the oil to water containing ammonia or amine. The emulsion can be prepared at room temperature. In some cases, particularly when concentrated emulsions are prepared, emulsification is enhanced by warming the mixture.

The emulsion can be applied to the absorbent carrier in particulate form by any known technique, such as spraying the carrier With the emulsion, or impregnating the carrier in a tank or reservoir. A good hydrophobic character is obtained if the emulsion is applied to provide from about 4 to about 30 grams of oil, and from about 0.2 to about 15 grams of ammonium or amine salt of carboxylic acid, per grams of carrier. More than this can be applied, if desired, but is not necessary.

After application of the emulsion, the water is removed by drying, and at the same time the ammonium or amine salt of the carboxylic acid is decomposed, so as to develop the hydrophobic character on the carrier. The temperature employed will depend upon the decomposition temperature of the ammonium or amine salt. These salts decompose at a temperature in excess of 100 C., but considerably higher temperatures can be used, if desired, to speed up the process. Temperatures up to 200 C. and even higher can be used, provided the carrier, the oil, and the salt residue are not damaged at such temperatures. The decomposition is normally complete in about onehalf hours time, but the heating can be continued for as long as ten hours, if desired.

The carrier can be dried and the ammonium or amine salt decomposed in separate steps, carrying out the drying at a low temperature, below a temperature at which the ammonium or amine salt is decomposed. This, however, requires a longer time, and is normally not practical, in a commercial operation,

The completion of the decomposition can be tested by testing the hydrophobic character of the carrier. When watenis no longer absorbed, or is absorbed only to an insignificant amount, the decomposition has proceeded far enough. even if it is incomplete, and the heating can be discontinued.

When the decomposition is sufficient, the oil will not be reemulsified when the carrier is put in contact with water, nor will the emulsifier itself be leached out.

The finished material is free-flowing, and will remain floating on the surface of water for a very long time. The material will preferentially absorb oil, to water, besides repelling the water, due to its hydrophobic surface. Ac-

cordingly, the material can be used simply by spreading it on the surface of water or over the ground. The spreading can be carried out manually, or by means of mechanical spreading apparatus. When spread on the surface of water, it can be spread some distance away from the oil, and allowed to drift towards the oil, or to be blown towards the oil by the wind. When it comes in contact with the oil, it will absorb the oil, and after the oil has been fully absorbed the oil-containing carrier can be collected by suitable sieving or filtering equipment, and then destroyed, or used as a fuel. It may also be possible to burn the oil-loaded absorbent on the surface of the water, particularly when the oil slick is far from shore. It is very easy to burn the oil-loaded absorbent, even in the presence of water, because of the very small amount, if any, of water that is absorbed.

The relative waterand oil-absorbing characteristics of the absorbent of the invention is determined in accordance with the following test, which is employed in the evaluations of the working examples.

Two grams of the absorbent are weighed into a cylindrical separating funnel 32 mm. in diameter, having a small plug of glass fiber in the drainage tube, so as to retain the absorbent in the funnel. Above the absorbent is placed a perforated plastic disk, so as to keep the absorbent in a stable bed in the funnel.

The water absorbability is determined by adding 20 ml. of distilled water, with the drain cock of the separating funnel closed. The water is allowed to stand over the absorbent material for five minutes, after which the drain cock is opened, and the water that has not been absorbed is allowed to run out. This usually takes less than five minutes, and is arbitrarily cut off at the end of this time. The volume of collected water is measured, and the difference between the water added and the measured amount of Water that runs out is reported as the waterabsorbing capacity, and is indicated in ml. of water per gram of absorbent.

The oil-absorbability is then determined in the same way, using 20 ml. of fuel oil No. 1. The oil is added after the water has been drained out, with the drain cock closed, and allowed to stand over the absorbent for five minutes. The drain cock is then opened, and the oil not absorbed collected over five minutes drain time, and its volume determined. The difference between the oil volume supplied and the volume of oil that runs out is stated as the oil-absorbing capacity, in ml. of absorbed oil per gram of absorbent.

The following examples in the opinion of the inventors represent preferred embodiments of the invention.

EXAMPLE 1 An emulsion was prepared by mixing 8.5 g. of fuel oil No. 1 with 1.5 g. of oleic acid. This mixture was added, with stirring, to 89.65 g. of a 25% aqueous ammonia solution, thus forming ammonium oleate in situ. The resulting aqueous emulsion was sprayed with a nozzle as a mist over 100 g. of sawdust, which was rotated by means of a mixer having counter-rotating heaters to ensure homogeneous absorption of the aqueous emulsion throughout. The moist sawdust was then transferred to a 30 x 40 cm. drying frame, with a bottom made of fine 270 mesh wire cloth. The sawdust was then dried in a drying oven at 120 C. to constant weight. This required three hours.

The absorbent showed good water-resistance, and good oil-absorbing capacity.

EXAMPLE 2 An absorbent was prepared in the same way as in example No. 1, but instead of fuel oil No. 1, fuel oil No. 5 was used. A hydrophobic absorbent having very good oil-absorbing capacity was obtained.

EXAMPLE 3 Example 1 was repeated, except that waste oil, i.e., used motor oil, was used in place of fuel oil No. l. A hydrophobic absorbent having very good oil-absorbing capacity was obtained.

EXAMPLE 4 Example 1 was repeated, except that in place of fuel oil No. 1, a mineral oil, Caltex 735, was used. A hydrophobic oil absorbent having very good oil-absorbing capacity was obtained.

EXAMPLE 5 To a drying plant constructed for the continuous drying of material according to the fluidized bed principle, sawdust was supplied at the rate of 200 kg. per hour. Above the conveying belt for the sawdust were mounted two spray nozzles, through which were supplied, per hour, 20 kg. of an aqueous emulsion of fuel oil containing 3 kg. of tall oil fatty acids emulsified in l. of water mixed with 0.7 kg. of a 25% aqueous ammonia solution. After the spraying step, the wet sawdust was fed through a screw conveyer, which simultaneously mixed the mass, and fed it through a fluidized bed entering an oven. In this bed, the sawdust was heated by passing hot drying air through the bed, and this air was so heated that the temperature of the outgoing dried heat-treated sawdust was at 125 to 130 C.

The waterand oil-absorbing capacities of the treated sawdust were determined in accordance with the standardized test. The sawdust had a water-absorbing capacity of 0.5 ml. per g., and an oil-absorbing capacity of 3.8 ml. per g. This compares with 4.5 ml. per g. of water-absorbing capacity, and 2.0 ml. per g. of oil-absorbing capacity, for the untreated sawdust.

EXAMPLE 6 To g. of finely shredded cellulose, so-called cellulose fluff, there was added by mechanical working 25 g. of an emulsion of 10 g. of herring oil emulsified with 1 g. of ammonium soap of technical stearic acid (Safacid 18/ 20- 60-3), and 14 g. of water. The resulting mass of cellulose fiutf was dried for three hours in an oven at to C EXAMPLE 7 To '10 kg. of peat of the usual commercial grade was added by mechanical mixing in a kneader 10 kg. of an aqueous emulsion composed of 1 kg. of fuel oil No. 5, emulsified with 0.2 kg. of ammonium soap of tall oil fatty acids having a 10% resin content, in 3.8 kg. of water. After anixing for ten minutes, the peat was spread as a 5 cm. thick layer in a heating chamber, and dried for two hours at to C. The waterand oil-absorbing capacities were then determined, using the standardized test. The water-absorbing capacity was 2.8 ml. per g., and the oil-absorbing capacity 7.0 ml. per g. This compares with a water-absorbing capacity of 4.6 ml. per g., and an oil-absorbing capacity of 3.1 ml. per g., for the untreated peat.

EXAMPLE 8 Upon 100 kg. of straw as it was fed through a straw chopping machine there was sprayed 40 kg. of an aqueous emulsion of 10 kg. of fuel oil No. 5 emulsified with 1.5 kg. of tall oil fatty acids having a 10% resin content and 0.4 kg. of a 25% aqueous ammonia solution in 38.1 kg. of water. The straw was chopped in the chopping machine to a length of approximately cm. The resulting emulsionimpregnated chopped straw was heat treated in a belt drying plant, where it was heated to 120 to 130 C. The water was thereby removed, and the emulsifier was decomposed. The resulting straw showed good water-resistance and a good oil-absorbing capacity, even after having first been moistened with water. In spite of the water treatment, the straw could be burned easily, after it had absorbed oil from atop a water surface.

The waterand oil-absorbing capacities were determined, using the standardized test. The water-absorbing capacity was 1.7 ml. per g., and the oil-absorbing capacity 2.9 ml. per g., as compared to 2.3 ml. per g. water-absorbing capacity and 1.9 ml. per g. oil-absorbing capacity, for the untreated straw.

EXAMPLE 9 200 g. of polyurethane foam Waste material from the manufacture of wall insulations, matresses and the like, was mixed by mechanical working in a dough mixer with 150 g. of an emulsion composed of g. of tallow, mixed with 5 g. of the monomethyl amine salt of tall oil fatty acids having a 10% resin content in 125 g. of water. The emulsion was prepared at C., so as to melt the tallow. After mixing for five minutes with the aqueous emulsion, the treated polyurethane foam material was transferred to a drying oven, Where it was heat-treated for six hours at to C. The absorbent floated well on water, and had a very good oil-absorbing capacity, while it showed very little tendency to absorb water.

EXAMPLE 10 EXAMPLE 1 1 A spool of absorbent paper weighing 100 g. was led over a plane disk while being wound on a second spool. Above the plane disk was placed a mist spray nozzle, and at a distance therefrom of approximately 1 m., in the direction of movement of the paper. A smooth 20 x 40 cm. plate heated by an electric heating element was disposed below the plane disk. The surface temperature of the plate was maintained at 150 to 170 C. Over the paper there was sprayed through the spray nozzle a mist of 100 g. of an aqueous emulsion composed of 10 g. of fuel oil No. 5 emulsified by 2 g. of the ammonium soaps of tall oil fatty acid having a 22% resin content in 88 g. of

water. The paper was then slowly passed along the disk over the heating plate, whereupon the water was evaporated, and the emulsifier was decomposed. The treated paper showed a very good resistance to water, and was well adapted to absorb oil spilled from a water or ground surface. The paper even after lying on a water surface for a long time could absorb oil, and thereafter could easily be ignited to destroy the oil.

EXAMPLE 12 200 g. of cork waste was mixed in a dough mixer with 100 g. of an emulsion composed of 20 g. of fuel oil No. 5 mixed with 5 g. of stearyl amine, which solution with stirring was caused as a thin jet to run down into 72 g. of water mixed with 3 g. of acetic acid. The cork waste treated with this emulsion was worked mechanically for ten minutes, after which it was heat-treated as a 2 cm. thick layer in an oven at to C. The resulting cork mass was water-repellent, and showed very good oilabsorbing capacity, even after having first been wetted with water.

EXAMPLE 13 10 kg. of bark waste was spread in a layer approximately 5 cm. deep, after which 20 kg. of emulsion was sprayed over it by a spray nozzle. This emulsion was prepared by adding to 1 kg. of fuel oil, 0.15 kg. of coconut oil fatty amine reacted with 2 moles of ethylene oxide per mole of coconut fatty amine; the resulting solution then was poured slowly, with stirring, into 18.75 kg. of water mixed with 0.10 kg. of formic acid.

The bark treated with this emulsion was placed in an oven as a layer approximately 10 cm. thick. The oven was held at to C. for three hours, after which the absorbent was taken out. The absorbent was water-repellent, and showed a very good oil-absorbing capacity, even after it had been subjected to treatment with water.

EXAMPLE 14 For comparison purposes, sawdust was treated in three different ways to prepare it as a carrier for oil, while a sample was reserved untreated, as a control (Control A).

Control B Another sample was treated with 10% of its weight of fuel oil No. 5, dissolved in isopropanol, after which the isopropanol was distilled off by heating.

Control C Another sample was treated with 10% of its weight of stearic acid, in place of fuel oil. The stearic acid was dissolved in isopropanol, and the isopropanol was distilled off by heating.

The last sample (Example 14) of the sawdust was treated with 10% of its weight of fuel oil No. 5, emulsified with the ammonium salt of tall oil fatty acids, and then heat-treated as in Example 5.

The time required before the four sawdust materials sank in water was determined, as also was the amount of oil absorbed, using the standardized test. The following results were obtained:

weight 01' fuel oil No. 5 emulsified with the ammonium salt of tall oil fatty acid, thereafter heat treatment.

It is apparent that Example 14, the sawdust treated in accordance with the invention, was extraordinarily waterrepellent, as compared to the other samples. Also, its oilabsorbability was increased, being nearly double that of the untreated sawdust (Control A), and also exceeding that of the other two samples (Controls B and C) which had the disadvantage of a very high water-absorbability.

Having regard to the foregoing disclosure, the following is claimed as the inventive and patentable embodiments thereof:

1. A process for preparing an oil absorbent capable of preferentially absorbing oil in the presence of water, and that will float on water when loaded with oil, which comprises impregnating an absorbent carrier that is capable of floating on water with an emulsion of a mineral, animal or vegetable oil in water, emulsified by a heat-decomposable ammonium or amine salt of an aliphatic or cycloaliphatic carboxylic acid having the formula:

wherein R is selected from the group consisting of hydrogen and aliphatic and cycloaliphatic hydrocarbon radicals having from one to about twenty-five carbon atoms, and R R and R are the same or different, and are selected from the group consisting of hydrogen and aliphatic and cycloaliphatic hydrocarbon groups having from one to about twenty-two carbon atoms, and heating the impregnated carrier at an elevated temperature above 35 C. to decompose the salt and form a hydrophobic residue thereon in the presence of the oil, thereby rendering the carrier hydrophobic and water-repellent, so that Water is not absorbed in a significant amount, and oil is absorbed preferentially, even in the presence of water.

2. A process according to claim 1, in which the heating is at a temperature between about 100 and about 200 C.

3. A process according to claim 1, in which the salt is of an amine volatile at the decomposition temperature.

4. A process according to claim 1 in which the emulsifier is a salt of ammonia or of a mono-, dior trialkyl amine having from one to five carbon atoms in the alkyl groups and of a saturated or unsaturated fatty acid having from twelve to twenty-five carbon atoms.

5. A process according to claim 1, in which the emulsifier is a salt of a monoor dialkyl amine having from eight to twenty-two carbon atoms in the alkyl groups and formic acid or acetic acid.

6. A process according to claim 1, in which the emulsion is incorporated in the carrier in an amount up to 30% by weight of the carrier, and the water is evaporated at a temperature exceeding the decomposition temperature of the emulsifier.

7. A process according to claim 1 in which the carrier is a light-weight material having a density of less than water and of a highly absorbent nature, selected from the group consisting of cellulosic material and sponge and foam plastic material.

8. A process according to claim 7 wherein the cellulosic material is selected from the group consisting of sawdust, Wood shavings, wood chips, cork, straw, cellulose pulp, cellulose fluff, shredded cellulose, cellulose linters, bark, paper, cardboard and hardboard.

9. A process according to claim 7 in which the plastic material is selected from the group consisting of regenerated cellulose sponge, polyurethane, polyvinyl chloride, polyethylene, polypropylene, polystyrene, nylon and vinyl chloride-vinyl acetate copolymer sponge and foam material, in particulate form.

10. A process according to claim 1 in which from two to three of the R R and R radicals is hydrogen, and the third is hydrogen or alkyl.

11. A process according to claim 1 in which the R radical is aliphatic.

12. An oil absorbent capable of preferentially absorbing oil in the presence of water and that will float on water when loaded with oil, prepared in accordance with the process of claim 1.

References Cited UNITED STATES PATENTS 2,464,204 3/1949 Baker 21040X 3,382,170 5/1968 Pape 210-40X 3,464,920 9/1969 Pirson et al 2l040X PATRICK P. GARVIN, Primary Examiner US. Cl. X.R.