US3539310A

US3539310A - Hydrocarbon gelling process using aluminum soap thickeners with surface active agents

Info

Publication number: US3539310A
Application number: US514135A
Authority: US
Inventors: Leo Finkelstein; Sidney J Magram; Leonard Cohen; William T Gregory
Original assignee: US Department of Army
Current assignee: US Department of Army
Priority date: 1955-06-08
Filing date: 1955-06-08
Publication date: 1970-11-10
Anticipated expiration: 1987-11-10

Description

3,539,310 Patented Nov. 10, 1970 Int. Cl. Cl 7/02 US. Cl. 44-7 9 Claims The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment to us of any royalty thereon.

The invention relates to the thickening of gasoline by aluminum soaps.

Gasoline, thickened or gelled by small quantities (about 1 to 12%) of aluminum soaps of the higher carboxylic acids, is important as an incendiary in warfare. Various aluminum soaps have been used, the best known being napalm, the aluminum soap of a mixture of oleic and naphthenic acids and coconut oil fatty acids disclosed and claimed in US. Pat. No. 2,606,107 to Louis F. Fieser. More recently, improved results have been obtained by the use of about 0.75 to 4% of aluminum octoates, notably aluminum hydroxy di-(2-ethyl hexoate) and the isooctoates disclosed in applications, Ser. Nos. 321,747 and 466,242, filed Nov. 20, 1952 and Nov. 1, 1954, respectively, by Leonard Cohen. These applications have ma tured into Pats. 2,741,629 and 2,718,462, respectively.

One advantage of these thickened gasolines over other incendiary fuel lies in the fact that they may be produced in the field by mixing the dry soap with gasoline. The proper amount of soap is added to a batch of gasoline and the mixture agitated until thickening occurs. The gel is then allowed to stand, or cure, for a certain length of time. During the curing period the gel develops elasticity.

It is desirable that the time of mixing, or vortex time, and the cure time be as short as possible, particularly to make it possible to use continuous rather than batch mixing and prompt use of filled bombs or flamethrowers. It is also desirable that the gel be as high in consistency as possible for a given amount of thickening agent, that it be highly elastic, and that it be stable over a long period of time.

We have found that the vortex time and the cure time can be shortened while retaining or enhancing the other desirable qualities by adding to the gasoline, prior to the r addition of the aluminum soap, a minor amount of nonionic surface-active agent, and that particular improvement can be obtained by the further addition, together with the surface-active agent, of certain small amounts of water. The improvement is particularly marked when the soap is aluminum hydroxy di-(2-ethyl hexoate).

While we do not wish to be bound by theory, we believe the explanation of the improved results to be as follows. In the process of formation of aluminum soaps by aqueous metathesis from sodium soap and aluminum salts in the presence of excess sodium hydroxide, aluminum hydroxide is formed together with the aluminum soap. This aluminum hydroxide is hydrophilic in nature and obstructs access of the hydrocarbons to the aluminum soap, thereby retarding gelation. It is believed that the addition of surface-active agents containing water causes hydration a hydrophilic group which is nonpolar. Suitable hydrophilic groups are hydroxy, polyhydroxy, and polyoxethylene. The hydrocarbon and hydrophilic groups should be so balanced that the compound is readily soluble in hydrocarbons in the proportions employed and, for ease in preparing the gel, it is desirable that the compounds be liquid. While the entire genus of non-ionic surfaceactive agents appears to be usable, we have found the subgenus consisting of those containing the polyoxyethylene group to be definitely superior in that they combine to the highest degree the various desirable properties set out above.

As stated earlier, we have found that further improvement in the vortex time and cure time is produced by employing water together with the surface-active agent. While commercial forms of the surface-active agents frequently contain varying amounts of Water, we have found that optimum results are secured by the use of a narrow critical range of ratios of water to agent, extending from 10:90 to 15:85, by weight.

In order to secure mutual solubility of water and agent over a wide temperature range, it has been found desirable to employ a cosolvent such as isopropanol or the diethyl ether of diethylene glycol. A blend of water, agent, and cosolvent is prepared and then added to the gasoline or other hydrocarbon.

Suitable blends may contain the following ingredients in parts by weight:

Agent: Water: 15 10 Cosolvent: 100

A ratio of ten parts aluminum soap to one part of such a wetting agent blend has proved effective in the preparation of hydrocarbon gels ranging from 0.75 to 4% by weight of aluminum soap.

When all the desired characteristics are taken into accound, two of the most desirable surface-active agents employed to date are:

Trade name: Chemical nature Triton X-45 Octylphenoxypolyethoxy ethanol (average of about 5 ethoxy groups).

Atlas 6-125 6 Polyoxyethylene sorbitol esters of mixed fatty and resin acids (tall oil acids).

The following examples illustrate the improvement attained by use of our invention.

EXAMPLE I-(Control) In a laboratory mixer, four percent of aluminum hydroxy di-(Z-ethyl hexoate), which had been formed by reacting aluminum sulfate or aluminum chloride with sodium 2-ethyl-hexoate in an aqueous solution of sodium hydroxide, was added to gasoline and the electric stirrer rotated at a fixed speed. As the mixture thickens, the level of the vortex rises about the rod of the stirrer. The time was noted for the level to rise from a predetermined initial level to a fixed point on the rod. This time is used as the vortex time. While the test is empirical in its choice of conditions, it is useful because it gives a quantitative measure of the time a thickener must be mixed in the field before it is allowed to stand or cure. The cure time was then determined by allowing the mixture to stand and noting the point at which elasticity developed.

On a series of tests as described above, the following results were secured:

Vortex time-2 0 to 40 minutes Cure time- 24 hours Gardner consistency after 24 hrs-205 3 EXAMPLE n The tests were repeated a sdescribed in Example I, except that there was first added to the gasoline one part of a surface-active agent/water/cosolvent blend as described above for each ten parts of aluminum soap, and the soap was then introduced.

In a series of tests, using Atlas G-1256 and Triton X-45 as the agent, the following results were obtained:

Vortex time-less than 3 minutes Cure timeabout minutes Gardner consistency after 24 hrs.-65(l to 700 TABLES OF DATA said gasoline a nonionic surface active agent selected from the group consisting of polyoxyethylene sorbitol esters of mixed tall oil acids, octylphenoxypolyethoxy ethanol and higher fatty acid derivatives of polyoxyethylene sorbitan, then adding an aluminum hydroxy soap of at least one higher carboxyllic acid selected from the group consisting of higher fatty acids and mixtures of higher fatty acids and naphthenic acids, the amount of said soap being about one to twelve percent by weight of the gasoline and the amount of surface active agent being about five percent by weight of said soap, stirring the mixture of gasoline, soap and agent until it thickens and finally allowing the thickened mixture to stand until it develops elasticity.

2. A process as defined in claim 1 wherein the surfaceactive agent consists essentially of a higher fatty acid derivative of polyoxythylene sorbitan.

3. A process as defined in claim 1 wherein said agent-non-ionie] Vortex time,

minutes Trade name Chemical nature (at 77 F.)

(A) Polyoxyethylene sorbitan and sorbitol fatty acid derivatives Tween 85 Polyoxyethylene sorbitan trioleate 4. 0 Tween 8l Polyoxyethylene sorbitan monooleate 2. Tween 80. do 3. 0 Tween 65. Polyoxyethylene sorhitan tiistearate 4. 5 Tween Poiyoxyethylene sorbitan monostearate. t. 3. -3 Tween 40. lolyoxyethylene sorbitan monopalmitate 2. 8 Tween 20. a Polyoxyethylene sorbitan monolaurate 3, 5 Atlas G2854. lolyoxyethylene sorbitol tetraoleate. 5. 5 Atlas fir-2855" Polyoxyethylene sorbitol pentaoleate 7. 5

(The preferred agent Atlas G-1256 is closely related to this group) (B) Alkyl polyoxyethylene alcohols 0 0x0 alcohol-4.5 moles ethylene oxide. 4. 5

C oxo alcohol6.6 moles ethylene oxide. 8. 9

. Cm 0x0 alcohol-93 moles ethylene oxide- 9. 9

C13 oxo alcohol-3.3 moles ethylene oxide 6. 0

C 3 oxo alcohol5.2 moles ethylene oxide 5. 5

C13 0x0 alcohol-ea. 12 moles ethylene oxide 5. 2

Esso-l53 0 0x0 aleohol 5.9 moles ethylene oxide.-." 7. 1

(C) Alkyl-aryl polyether alcohols Igepal 00-630 Alkyl phenoxy polyoxyethylene ethanol..." 3. 8 Igepal (IA-630.. do 4. 0 Igepal C0430 o 4. U Oronite dispersant N I-C. Alkyl phenyl polyethoxyethanol. 3. 5 Triton X-l55 Alkyl aryl polyether alcohol 3.8 Triton Xl00 do 3. 8 Te1gitol-NPX.. Alkyl phenyl polyethylene glycol ether 2. 8 Tergitol-TMN Alkyl ether of polyethylene glycol 3.0 Tergitol-CW Alkyl aryl polyglyeol others 2. 7 (The preferred agent Triton X-45 belongs to this group. It contains fewer ethoxy groups than the other members and is therefore more readily soluble in gasoline.)

(D) Aliphatic polyoxyethylene ether type Sterox AJ Aliphatic polyoxyethylene ether type 3.0 Sterox SE Aliphatic polyoxyethylene thio ether. 3. 7 Sterox SK do 4. 0 The following non-ionic agents not belonging to the preferred subgenus were also found to be operative (E) Sorbitan fatty-acid derivatives Span Sorbitan monooleate 5. 0 Span 60. a Sorbitan monostearate 1.8 Span 40-.. Sorbitan monopalmitate. 2. 3 Span 20. Sorbitan monolaurate 2. 7 ArlaeeL... Sorbitan sesquioleate 0 (These gave satisfactory results, but arefspllids, retguiring a dissolving step before addition 0 e soap.

(F) Higher alcohols Undecanol. Pentadecanol I-Iep tadeeanol surface-active agent consists essentially of polyoxyethylene sorbitol esters of mixed tall oil acids.

4. A process as defined in claim 1 wherein said surface-active agent consists essentially of octylphenoxypolyethoxy ethanol having an average of about five ethoxy groups to the molecule.

5. A process as defined in claim 1 wherein water is added together with said agent, the ratio of water to agent ranging from 10:90 to 15:85.

6. A process as defined in claim 2 wherein water is added together with said agent, the ratio of water to agent ranging from 10:90 to 15:85.

7. A process as defined in claim 3 wherein water is added together with said agent, the ratio of water to agent ranging from 10:90 to 15:85.

8. A process as defined in claim 4 wherein water is added together with said agent, the ratio of water to agent ranging from 10:90 to 15:85.

9. A process as defined in claim 1 in which the aluminum soap is aluminum hydroxy di-(2-ethy1 hexoate).

6 References Cited UNITED STATES PATENTS 12/1945 Minich 252-316 12/ 1949 Mysels 447 X 8/1952 Fieser 447 9/1955 Cohen 447 FOREIGN PATENTS 4/ 1942 Great Britain.

BENJAMIN R. PADGETT, Primary Examiner US. Cl. X.R.

Claims

1. A PROCESS OF GELLILNG GASOLINE COMPRISING ADDING TO SAID GASOLINE A NONIONIC SURFACE ACTIVE AGENT SELECTED FROM THE GROUP CONSISTING OF POLYOXYETHYLENE SORBITOL ESTERS OF MIXED TALL OIL ACIDS, OCTYLPHENOXYPOLYETHOXY ETHANOL AND HIGHER FATTY ACID DERIVATIVESS OF POLYOXYETHYLENE SORBITRAN, THEN ADDING AN ALUMINUM HYDROXY SOAP OF AT LEAST ONE HIGHER CARBOXYLLIC ACID SELECTED FROM THE GROUP CONSISTING OF HIGHER FATTY ACIDS AND MIXTURES OF HIGHER FATTY ACIDS AND NAPHTHENIC ACIDS, THE AMOUNT OF SAID SOAP BEING ABOUT ONE TO TWELVE PERCENT BY WEIGHT OF THE GASOLINE AND THE AMOUNT OF SURFACE ACTIVE AGENT BEING ABOUT FIVE PERCENT BY WEIGHT OF SAID SOAP, STIRRING THE MIXTURE OF GASOLINE, SOAP AND AGENT UNTIL IT THICKENS AND FINALLY ALLOWING THE THICKENED MIXTURE TO STAND UNTIL IT DEVELOPS ELASTICITY.