Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/10—Liquid carbonaceous fuels containing additives
  • C10L1/14—Organic compounds
  • C10L1/18—Organic compounds containing oxygen

Definitions

• An object of this invention is to alleviate the thermal stability problems injet fuels. Another object is to provide new jet fuel compositions which are characterized by a high degree of thermal stability problems in jet fuels in a simple and inexpensive manner. A still further object is to provide processes of inhibiting deterioration of jet fuel normally tending to occur at elevated temperatures below the cracking temperatures of the fuel. Other objects will beapparent from theensuing description.
• thermore the additives of this invention do not introducesecondary problems in use, such as jet fuel foaming at high altitudes, emulsification difficulties, interference with low-temperature flows, and the like.
• the present invention represents a substantial contribution :to'the jet fuel art.
• the 2,6-dialkyl phenol jet fuel additives have the formula:
• R and R are alkyl groups which preferably contain up to about 12 carbon atoms.
• Preferred jet fuel additives of this invention are 26;
• dialkyl phenols in which at least one of the alkyl groups is secondary or tertiary i.e., is branched on the alpha carbon atom.
• Particularly preferred as-jet fuel additives are 2,6 di-tert-butyl phenol and 2-methyl-6-tert-buty1 phenol.
• the jet fuels whose thermal stability is greatly improved pursuant to this invention are principally hydrocarbon fuels which are heavier than gasoline, i.e., distilled liquid hydrocarbon fuels having a higher endpoint than gasoline.
• the jet fuels can be comprised of distillate fuels and naphthas and blends of the above, including blends with lighter hydrocarbon fractions, so long as the endpoint of the final jet fuel is at least 435 F. and preferably greater than 480 F.
• the" jet fuels which are employed according to this invention can contain certain other ingredientssuch asalcohols or the like, provided the resulting fuel-blend meets the specifications imposed upon jet fuels.
• Typical. jet fuels improved according to this invention include. JP-3, a mixture of about 70 percent gasoline and 30 percent light distillate having a 90 percent evaporated pointjof 470? F.; JP-4, a mixture of about 65 percent ⁇ gasoline and 35 percent light distillate, a fuel especiallydesignedfor high altitude performance; JP5, an especially fractionated kerosene; high flash point-low freezing point kerosene, etc.
• Example II To 100,000 parts of Fuel B is added 100 parts (0.1 percent) of 2-rnethyl-6-ethyl phenol disolved in 500 parts of methanol. The resulting fuel possesses improved thermal stability properties.
• Example Ill With100,000 parts ofFuel C is blended 50 parts (0.05 percent) of 2-methyl-6isopropyl phenol. The resulting fuel blend possesses superior thermal stability characteristics.
• Example V With 100,000 parts of Fuel E is blended 80 parts (0.08 percent) of 2,6-di-tert-butyl phenol. The resulting fuel blend possesses enhanced thermal stability properties.
• Example VI To 100,000 parts of Fuel F is added 200 parts (0.2' percent) of 2,6-diisopropyl phenol dissolved in" 1500 parts of isopropanol. After mixing, the resulting fuel blend is found to possess enhanced thermal stability properties.
• Example VII Fuel C is blended with a lighter hydrocarbon fraction to give a final jet fuel having an endpoint of 435 F. To 100,000 parts of the resultant fuel is added parts (0.09 percent) of 2,6-di(2-dodecyl)' phenol; The resulting fuel possesses improved thermal stability characteristics.
• Example VIII To 100,000parts of a liquid hydrocarbon jetfuel having an endpoint of 550 F. "is addedparts (0.15 percent) of 2-isopropyl-6-tert-butyl phenol dissolved in-1500 parts of mixed xylenes. The resulting jet fuel possesses superior. thermal stability properties.
• Example IX With 100,000 parts of Fuel'A is blended 60 parts (0.06 percent) of 2-methyl-6-tert-amyl phenol; This fuel after mixing possesses improved thermal stability characteristics.
• Example X Y parts of 2,6-di-(l,l,3,3-tetramethylbutyl) phenpl is blended with 100,000 parts of Fuel B. The resulting jet fuel containing 0.17 percent of the phenol possesses ir nproved thermal stability characteristics.
• Example Xl With 100,000 parts of Fuel C is blended 70 parts (0.07 perc nt) f 2 -ethyl-6-tert-butyl phenol. Theres'ulting jet fuel blend possesses superior thermal stability character: istics.
• thisCFR fuel coker was-operated: without; a filter and without'heatv onthe filterfurnace. Thispermits allof the-tests to-be of equal and predetermined-duration so that-a direct comparison of'deposits from a given quantity of: fuel is provided; -In this-series of tests, the .preheater temperature was 400 F.', fuel-flowwas at arateof six pounds per hour, and each individual run wascarn'ed out foraperiodfof .150minutes.
• a jet fuel of this invention was prepared by blending 2- methyl-6-tert-butyl phenol with the above fuel at a concentration of 80 pounds per 100 barrels (approximately 0.025 percent by weight of additive).
• the additive-free base fuel was also rated in manner.
• the extent of the deposit formation on the preheater surfaces is a direct measure of the thermal stability of the fuel subjected to the test. Hence, the greater the coverage of the preheater surfaces with deposits, the greater is the thermal instability of the fuel.
• An additional criterion of the thermal stability of the fuels is the coloration of these deposits. If a light-colored deposit is formed, only a small amount of high temperature deterioration of the fuel has occurred. Thus, the darker the deposits, the more thermally unstable is the fuel.
• the fuel of this invention containing Z-methyl- 6-tert-butyl phenol caused a 43 percent reduction in the extent of the preheater surfaces covered by deposits.
• the deposits produced by the additive-free fuel were very dark brown to black in color, whereas the smaller amount of deposits produced from the jet fuel of this invention were of a brownish coloration.
• Similar effectiveness is achieved by using 2,6-di-tert-butyl phenol instead of 2-methyl-6-tert-butyl phenol.
• the jet fuels of this invention without exception possess superior thermal characteristics as compared with the corresponding additive-free fuels.
• Typical additives which can be used in the practice of this invention include such compounds as 2,6-dimethyl phenol; 2,6-diethyl phenol; 2,6-dipropyl phenol; 2,6-dibutyl phenol; 2,6-dioctyl phenol; 2,6-didecyl phenol; 2,6- didodecyl phenol; 2-metl1yl-6-ethyl phenol; 2-methyl-6- propyl phenol; 2-methyl-6-octyl phenol; 2-ethyl-6-butyl phenol; 2,6-diisobutyl phenol, and the like.
• Preferred additives of this invention include 2-methyl-6-isopropyl phenol; 2-methyl-6-tert-amyl phenol; 2-ethyl-6-(2-dodecyl) phenol; 2-methyl-6-(l,l,3,3-tetramethylbutyl) phenol; 2 ethyl-6-(1,l-2,2-tetramethylpropyl) phenol; 2,6-diisopropyl phenol; 2-ethyl-6-tert-butyl phenol; 2,6 di-sec-but-yl phenol; 2,6-di-(3-heptyl) phenol; 2,6-di-(3-nonyl)phenol; 2,6-di-(2-dodecyl) phenol, and the like.
• the particularly preferred additives of this invention are 2-methyl-6-tert-butyl phenol and 2,6-di-tert -butyl phenol. The methods of preparing many of these 2,6-
• dialkyl phenols are well known to those skilled in the art and can be found in the literature. An especially elegant process for preparing 2,6-dialkyl phenols in which at least one of the alkyl groups is branched on the alpha carbon. atom is described in co-pending application, Serial No. 426,556, filed April 29, 1954, now Patent No. 2,831,898.
• the amount of the additive used in the jet fuels of this invention can range from about 0.01 to about 0.2 percent by weight. Ordinarily, amounts of 0.02 to about 0.15 percent are found to be satisfactory for present-day jet fuels. Variations from these concentration ranges are permissible. For example, in jet fuels initially possessing a fair degree of thermal stability, very small amounts of the additives are suificient to improve the thermal stability characteristics of such fuels and, in some cases, provide improved storage stability properties. On the other hand, where the jet fuel initially has a very poor thermal stability, larger amounts (about 0.05 to 0.2 percent by weight or more) can be effectively used.
• solvents for the 2,6-dialkyl phenols are frequently advantageous. While the solubility of these compounds in jet fuels is sufficiently high to provide the desired concentrations, blending procedures are simplified by predissolving these thermal stabilizers in a suitable solvent. The resulting formulations can then be conveniently and readily blended with the jet fuels.
• suitable solvents for this purpose include benzene, toluene, xylene, acetone, methylethyl ketone, methanol, ethanol, isopropanol, methyl isobutyl carbinol, and the like.
• ketones and alcohols containing up to about 6 carbon atoms and liquid aromatic hydrocarbons containing 6 to 18 carbon atoms are excellent solvents.
• Other materials that can be used in the jet fuels of this invention are anti-rust additives, dispersants, and, in general, additives which do not adversely affect the high temperature stability of the fuels,
• Distilled hydrocarbon jet fuel having an endpoint of at least about 480 F. containing from about 0.01 to about 0.2 percent by weight of a 2,6-dialkyl phenol having the formula:
• R and R are alkyl groups containing up to about 12 carbon atoms each.
• Distilled hydrocarbon jet fuel having an endpoint of at least about 480 F. containing from about 0.01 to about 0.2 percent by weight of a 2,6-dialkyl phenol in which at least one of the alkyl groups is branched on the alpha carbon, said phenol having the formula:
• R and R are alkyl groups containing up to about 12 carbon atoms each.
• composition of claim 2 wherein said phenol is 2-methyl-6-tert-butyl phenol.
• composition of claim 2 wherein said phenol is 2,6-di-tert-butyl phenol.
• R andR are alkyl groups containing up to about 12 carbon atoms each.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Health & Medical Sciences (AREA)
• Emergency Medicine (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Priority Applications (4)

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Cited By (6)

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Citations (1)

• 0
  • BE BE562478D patent/BE562478A/xx unknown
• 1956
  • 1956-11-21 US US623542A patent/US3019097A/en not_active Expired - Lifetime
• 1957
  • 1957-11-08 GB GB34859/57A patent/GB859259A/en not_active Expired
  • 1957-11-19 DE DEE14967A patent/DE1057383B/de active Pending

Patent Citations (1)

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