United States Patent (19) 11 Patent Number: 4,971,597 Gartner 45 Date of Patent: Nov. 20, 1990

(54). SOLID FUEL WITH Primary Examiner-Peter A. Nelson HYDRATION INHIBITING COATNG Attorney, Agent, or Firm-Leitner, Greene & 75 Inventor: Scott Gartner, Baltimore, Md. Christensen 73) Assignee: RA Investment Corporation, 57 ABSTRACT Baltimore, Md. There is disclosed a process for making a solid alcohol 21 App. No.: 281,672 fuel which comprises:p (1) forming an aqueous slurry of 21 pp O 9 an alcohol with a cellulosic derivative having a hydra 22 Filed: Dec. 9, 1988 tion inhibiting coating and (2) then adding an effective 51) Int. Cl...... C1OL 7/00 amount sufficient to increase the pH level above 8, of a 52 U.S. C...... 44/267; 44/313 caustic materialso as to affect hydration and solidifica 58 Field of Search ...... 44/7.1, 7.6, 7.4, 7.7 tion. The preferred alcohols are and , 56 References Cited however alcohols having from one carbon to ten car bon atoms may be used. The caustic material is prefera U.S. PATENT DOCUMENTS bly sodium hydroxide or potassium hydroxide. The 2,613,142 10/1952 Wiczer ...... 44/7.4 cellulosic derivative is typically a cellulose ether such as 2,838,384 6/1958 Sloan et al. 44/7.4 hydroxypropyl methyl cellulose. The hydration inhibit 3,072,467 1/1963 Wiczer ...... 44/7.4 ing coating on the cellulosic derivative is an acid coat 3,334,053 8/1967 Audrieth et al...... 44/7.4 ing or a glyoxylated surface. The composition further 3,754,877 8/1973 Klug ...... - ... 44/7.4 contains a smoke suppressant such as aluminium oxide 3,824,085 7/1974 Teng ...... 44/7.4 3,964,880 6/1976 Siegrist ...... 44/7.4 trihydrate. 4,141,766 2/1979 Cameron et al...... 149/2 4,575,379 3/i986 Browning ...... 44/7.4 38 Claims, No Drawings 4,971,597 1 2 ily converted to gel form. The present invention further SOLID ALCOHOL FUEL WITH HYDRATION contemplates a process for making a solid alcohol fuel INHIBITING COATING which comprises mixing an alcohol solution with a cellulose derivative having a hydration inhibiting coat TECHNICAL FIELD OF THE INVENTION 5 ing so as to form a slurry and then adding an effective This invention relates to methods of making solid amount sufficient to increase the pH level above 8, of a alcohol fuels which process uses a cellulose derivative caustic material so as to effect hydration and solidifica having a hydration inhibiting coating. This invention tion. Various carbon alcohols containing one carbon to further relates to improved methods of making solid the carbon atoms, and combinations thereof, may be alcohol fuels which allows for in-situ production. An 10 employed to provide a desired flame characteristic. other aspect of the invention relates to solid alcohol fuel Various salts may be added to similarly control flame compositions which incorporate a cellulose derivative color. In a preferred embodiment, a hydroxypropyl having a hydration inhibiting coating during the pro methyl cellulose having a hydration inhibiting coating cessing. A further aspect of the invention are solid alco such as an acid coating or a glyoxylated surface is uti hol fuels which do not produce any soot upon burning 15 lized to provide a low cost flammable fuel which is and therefore have more appeal to the consumer. The stable and conveniently packaged, stored and handled. present invention further relates to in-situ formation of The present invention further contemplates a solid solid alcohol fuels. alcohol fuel comprising: (1) an alcohol, (2) a cellulosic derivative having a hydration inhibiting coating; (3) a BACKGROUND OF THE INVENTION caustic material, and (4) a smoke suppressant such as The present invention relates generally to combusti alumina trihydrate. ble fuel compositions and is particularly directed to a The inhibition also provides an alcohol slurry con fuel composition in the form of a solid gel for use in prising: (1) an alcohol; (2) a cellulosic derivative having heating chafing dishes and the like, as flares, and for a hydration inhibiting coating. decorative lighting purposes. 25 The invention further provides a process for the in A well-known, commercially available gel fuel situ production of a solid alcohol fuel which comprises: widely used today is based on a lower molecular weight (1) forming an aqueous slurry of an alcohol with a hy alcohol such as ethanol or methanol gelled by special, droxyl propyl methyl cellulose which has a hydration proprietary techniques with, e.g., nitrocellulose. While inhibiting coating and (2) placing the slurry into a re materials of this type have enjoyed considerable com 30 ceptacle having an effective amount of a caustic mate mercial success, there is room for improvement over rial to increase the pH of the resulting solid fuel to about them. One obvious shortcoming of the prior caustic is 8 or above. that they exhibit syneresis upon standing for an ex In the preferred embodiment of the present invention, tended period of time. Thus, a freshly opened can of the preferred alcohols are methanol and ethanol or gelled fuel may contain a layer of free liquid alcohol on 35 combination thereof. The preferred cellulosic deriva its surface which must be discarded prior to igniting the tive is a hydroxypropyl methyl cellulose which has a fuel or a hazardous flare-up will be experienced. hydration inhibiting coating such as an acid coat or a OBJECTS AND SUMMARY OF THE glyoxylated surface. INVENTION The appended claims set forth those novel features Accordingly, it is an object of the present invention which characterize the invention. However, the inven to provide an improved fuel for heating and cooking. tion itself, as well as further objects and advantages It is another object of the present invention to pro thereof, will best be understood by reference to the vide a combustible fuel gel particularly adapted for following detailed description of the preferred embodi heating chaffing dishes. 45 nets. It is a further object of the present invention to pro DETALED DESCRIPTION OF THE vide a combustible fuel particularly adapted for use in PREFERRED EMBODIMENTS cooking which has a controllable burn rate, and a wide range of flame characteristics. The present invention is directed to a fuel composi Yet another object of the present invention is to pro 50 tion and method of preparation therefor. The fuel is a vide a combustible fuel which offers minimal noxious combustible fuel particularly adopted for use in cook combustion by-products and produces no soot and ing, specifically chaffing dishes. The fuel can also be ashes. used for additional purposes such as heating and as a A further object of the present invention is to provide decorative light source. a low cost, conveniently packaged and safe fuel gel. 55 The main chemical components of the present inven A still further object of the present invention is to tion are alcohols, substituted cellulose derivatives, a provide a combustible fuel in stable gel form which caustic material and alumina trihydrate. The alcohols provides increased safety in storage, handling and use. which are suitable for carrying out the present inven Another object of the present invention is to provide tion are straight chain, secondary or tertiary C1-C10 a high alcohol content combustible fuel in a stable gel alcohols. Typical alcohols include methanol, ethanol, form. propanol, isopropanol, butanol, isobutyl alcohol, tertbu It is a further object of the present invention to pro tyl alcohol, pentanol, isopentyl alcohol, neopentyl alco vide a fuel composition adopted for indoor use which hol, hexanol, heptanol, octanol, nonanol, and decanol as produces neither ashes nor smoke and is economical to well as all possible positional isomers of the above alco SC. 65 hols. Cyclic alcohols such as cyclopropanol, cyclobu The present invention contemplates a combustible tanol, cyclopentanol, , cycloheptanol, cy fuel comprised of alcohol, water and a cellulose deriva clooctanol, cyclononanol and cyclodecanol can also be tive having a hydration inhibiting coating which is eas used in the present invention. The preferred alcohols 4,971,597 3 4 for carrying out the present invention are the lower material is added so as to effect gelation of the alcohol carbon alcohols such as methanol, ethanol, propanol fuel. and isopropanol. The cellulosic materials can also be treated with The compositions of the present invention also con other C3-C8 dialdehydes as described above or can be tain a smoke suppressant. A typical smoke suppressant coated with an acid material such as polymers having which is suitable for carrying out the present invention acidic groups. Polymers having acidic group can be is alumina trihydrate. Other smoke suppressant materi derived from monomers such as acrylic or methacrylic als can be interchanged with the alumina trihydrate and acid and maleic acid and they can be copolymerized they include the alkali metal borates alone or in combi with other ethylenically unsaturated monomers by stan nation with ammonium , ammonium chloride and O dard polymerization procedures well known in the ammonium phosphate. Other materials such as the anti prior art. A typical acid coating polymer would be mony oxide derivatives are also suitable. Aluminium polyacrylic acid. trihydrate sold by Solene Industries under the trade The caustic material which is needed to start hydra designations of SB-30, Onyx Elite series, FRE, Micral tion can be any alkaline material which is effective to 932, Micral 855, SB-805, SB-331/SB-332, SB-631/SB 5 raise the pH to a level of 8 or above. Typical caustic 632, SB-431/SB-432, SB-335/SB-336 and Micral 632 materials include lithium hydroxide, sodium hydroxide, can all be used in the compositions and method of the potassium hydroxide, cesium hydroxide, lithium car present invention. bonate, sodium carbonate, potassium carbonate, cesium The cellulosic derivatives which are useful in carry carbonate, rubidium carbonate, calcium hydroxide, ing out the present invention are cellulosic alkyl ethers magnesium hydroxide, strontium hydroxide, strontium and hydroxyalkyl alkyl ethers. The cellulosic deriva carbonate, barium hydroxide, barium carbonate, beril tives of the present invention have a special coating lium carbonate or any other useful material which im present on their surface which retards their hydration parts alkalinity to the alcohol slurry. when mixed with the alcohol solution. A typical coat 25 In the process of the present invention, for example, ing on the cellulose derivatives is an acid coating such 200 ml. of alcohol and 50 ml. of water are mixed first as a polyacrylic acid coating. The cellulosic derivative and then 10 grams of Methocel J75MS is added to ob can also be surface treated with glyoxal as shown in tain a very aqueous slurry, which stays aqueous for a U.S. Pat. No. 3,072,635. long period because of the coating that is present in the Typical cellulosic ether derivatives include methyl Methocel. The coating material on the Methocel inhib cellulose, ethyl cellulose, propyl cellulose and buty its hydration. To the above solution there is added an cellulose. Among the preferred cellulose derivatives are alkaline material to start hydration and to raise the pH the hydroxyalkyl alkyl celluloses. Typical hydroxyalkyl level to 8 or above. The use of a specially treated cellu alkyl celluloses include hydroxypropyl methyl cellu lose derivative allows for solidification of the alcohol in lose, hydroxyethyl ethyl cellulose, hydroxypropyl ethyl 35 individual cans. While the solution is still very aqueous cellulose, hydroxyethyl methyl cellulose, hydroxypro it is poured into a can containing a caustic material and pyl propyl cellulose, hydroxyethyl propyl cellulose. hydration and solidification occurs instantaneously. The preferred cellulose derivative for carrying out the The process of the present invention avoids the prob present invention is a hydroxypropyl methyl cellulose lems of pumping and pouring which are associated with sold by the Dow Chemical Company under the name other cellulosic materials not having a hydration inhib Methocel J75MS. The Methocel J75MS has a coating iting coating. which inhibits hydration. The coating is of an acid na The alcohol solution containing the cellulosic deriva ture or glyoxylated. The coating which inhibits the tive having a hydration inhibiting coating solidifies hydration allows for the manufacture of an all solid fuel immediately upon contact with the caustic material in a fast and effective manner. 45 which has been placed in the can. No excess liquid The hydroxypropyl methyl cellulose derivative of remains after solidification. the present invention contains from about 5 to 12 per The process of the present invention is carried out as cent by weight of hydroxypropoxy groups and from follows: A solution containing 200 mi. of alcohol and 50 about 27 to 30 percent by weight of the cellulose ether. ml. of water is mixed with 10 grams of Methocel J.75MS Advantageously, the cellulose ether derivative that is 50 to form a fluid slurry and then the resulting slurry is employed contains from about 7 to 12 percent by placed into a receptacle having an effective amount of a weight hydroxypropoxyl groups and from about 28 to caustic material to increase the pH of the resulting com 30 per cent by weight of methoxyl groups. Any viscos position to about 8 or above. The amount of sodium ity grade of the cellulose ether that is available may be hydroxide is typically 2 to 4 grams. utilized satisfactorily. The preferred derivative is one 55 sold by the Dow Chemical Company under the trade The solid fuels of the present invention typically designation Methocel J75MS. The Methocel J75MS has contain 60-80% by weight alcohol, 5-35% by weight a special coating which inhibits the hydration of the water, 1-4% by weight of the cellulosic derivative, and cellulosic derivative. up to 1% of a smoke suppressant material such as alu The preferred methocel material for carrying out the mina trihydrate. present invention is prepared by methods described in EXAMPLES U.S. Pat. No. 3,072,635 and more specifically as shown in Examples 6 and 7 of the aforementioned patent. As Example 1 shown in the 635 patent, the preferred materials for A solution containing 170 grams of isopropanol and carrying out the present invention are glyoxylated with 65 50 grams of water is mixed with 10 grams of Methocel small amounts of glyoxal to give the cellulosic material J75MS. To the resulting slurry there is added 3 grams of easy dispensibility. The treatment with glyoxal also sodium hydroxide wherein immediate gelation and hy inhibits the hydration of the material until a caustic dration takes place. 4,971,597 5 6 30 per cent by weight of methoxy groups, based on the Example 2 weight of the cellulose ether. A solution containing 170 grams of methanol and 50 7. A process according to claim 1 wherein the alcohol grams of water is mixed with 10 grams of Methocel is selected from the group of straight chain C1-C10 J75MS. To the resulting slurry there is added 4 grams of 5 alcohols. sodium hydroxide wherein immediate hydration and 8. A process according to claim 7 wherein the alcohol solidification takes place. is selected from the group consisting of methanol, etha nol, propanol and butanol. Example 3 9. A process according to claim 1 wherein the alka A solution containing 170 grams of isopropanol and 10 line material is selected from the group consisting of 50 grams of water is mixed with 10 grams of Methocel sodium hydroxide and potassium hydroxide. J75MS. To the resulting slurry there is added 2 grams of 10. A process according to claim 1 wherein the hy sodium hydroxide wherein immediate hydration and dration inhibiting coating on the cellulosic derivative is solidification occurs. of an acid nature or a glyoxylic coating. 5 11. A process according to claim 1 wherein the hy Example 4 dration inhibiting coating reacts instantaneously with A masterbatch solution containing 1700 grams of said caustic material. ethanol and 500 of water is mixed with 100 grams of 12. A process according to claim 11 wherein the Methocel J75MS. The resulting slurry is quite fluid and hydration inhibiting coating reacts with the caustic is easily poured into individual cans (approximately 20 material to instantaneously form a solid alcohol fuel. 8-ounce containers) which contain 2-4 grams of sodium 13. A process for the instantaneous production of a hydroxide. The solution hydrates and gels immediately solid alcohol fuel which comprises: (1) forming slurry upon contact. The cans are sealed and then ready for of a liquid alcohol with a cellulosic derivative having a shipment. hydration inhibiting coating and (2) placing the slurry 25 into a receptacle having an effective amount of a caustic Examples 5 to 8 material to increase the pH of the resulting solid fuel to about 8 or above. Examples 1 through 4 are repeated as shown above 14. A process for the in-situ production of a solid except amounts ranging from 0.1% to 1% by weight of alcohol fuel which comprises: (1) forming an aqueous alumina trihydrate are added. The resulting solid alco 30 slurry of an alcohol with a hydroxypropylmethyl cellu hol fuels upon burning do not produce undesirable lose which has a hydration inhibiting coating and (2) smoke or unpleasant odors. placing the slurry into a receptable having an effective The present invention thus provides an improved fuel amount of a caustic material to increase the pH of the composition and method of preparation therefor. The resulting solid fuel to about 8 or above. gel form of the fuel composition of the present invents 15. A process according to claim 14 wherein the tion offer various advantages such as retarding of fuel alcohol is selected from the group consisting of metha evaporation particularly with respect to alcohol-based nol and ethanol. fuels, increased safety due to elimination of spill ha 16. A process according to claim 15 wherein the zards, and a controllable burn rate as determined by the caustic material is sodium hydroxide. amount of alcohol in the fuel. Reduced amounts of 40 17. A solid alcohol fuel comprising: alcohol will result in lower combustion temperatures (1) an alcohol; and reduced burn rates. In addition, the present inven (2) a cellulosic derivative having a hydration inhibit tion provides a fuel in gel form having a uniform viscos ing coating; and ity throughout which also ensures a more uniform burn (3) an alkaline material. rate throughout combustion of the entire fuel sample. 45 18. An alcohol slurry comprising: The addition of alumina trihydrate further eliminates ((1) an alcohol; and undesirable smoke and unpleasant odors. (2) a cellulosic derivative having a hydration inhibit What is claimed and desired to be secured by this ing coating. patent of the United States is: 19. The solid fuel of claim 17 wherein the alcohol is 1. A process for preparing a solid alcohol fuel which 50 methanol. comprises: mixing an alcohol solution with a cellulose 20. The solid fuel of claim 17 wherein the alcohol is derivative having a hydration inhibiting coating ethanol. thereby forming a slurry and then adding an effective 21. The solid alcohol fuel of claim 17 wherein the amount sufficient to increase the pH level above 8, of a cellulose derivative is hydroxypropyl methyl cellulose. caustic material so as to effect hydration and solidifica 55 22. The solid alcohol fuel of claim 17 wherein the tion. alkaline material is sodium hydroxide. 2. A process according to claim 1 wherein the cellu 23. The slurry of claim 18 wherein the alcohol is losic derivative is a cellulose ether. methanol. 3. A process according to claim 2 wherein the cellu 24. The slurry of claim 18 wherein the alcohol is lose ether is selected from the group consisting of 60 ethanol. methyl cellulose, ethyl cellulose and propyl cellulose. 25. The slurry of claim 18 wherein the alcohol is 4. A process according to claim 1 wherein the cellu methanol. losic derivative is a hydroxyalkyl alkyl cellulose. 26. The solid alcohol fuel produced by the method of 5. A process according to claim 4 wherein the cellu claim 1. losic derivative is hydroxypropyl methyl cellulose. 65 27. The solid alcohol fuel produced by the method of 6. A process according to claim 5 wherein the hy claim 13. droxypropyl methyl cellulose has 5 to 12 per cent by 28. The solid alcohol fuel produced by the method of weight of hydroxypropoxy groups and from about 27 to claim 14. 4,971,597 7 8 29. The composition of claim 17 produced the effective amount of a cellulose derivative having a hy dration inhibiting coating. method of claim 1. 35. A solid alcohol fuel comprising: 30. The composition of claim 17 produced by the (1) an alcohol; method of claim 13. 5 (2) a glyoxylated cellulose derivative; and 31. The composition of claim 17 produced by the (3) an alkaline material. method of claim 14. 36. The fuel of claim 35 further including an effective 32. The composition of claim 17 wherein the hydra amount of a smoke suppressant. tion inhibiting coating is an acid coating. 37. The fuel of claim 36 wherein the smoke suppres 10 sant is alumina trihydrate. 33. The slurry of claim 18 wherein the hydration 38. An alcohol slurry comprising: inhibiting coating is an acid coating. (1) an alcohol; and 34. A composition comprising an aliphatic alcohol (2) a glyoxylated cellulose derivative. having from one to ten carbon atoms and containing an xx 15

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