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, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/10—Liquid carbonaceous fuels containing additives
  • C10L1/103—Liquid carbonaceous fuels containing additives stabilisation of anti-knock agents
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
  • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
  • C07F7/24—Lead compounds

Definitions

• This invention relates to tetramethyllead associated with a specific hydrocarbon complement which confers upon the resultant composition an unusually great re sistance against the adverse consequences of thermal decomposition such as might occur upon exposure to heat.
• essentially pure i.e., highly concentrated-tetramethyllead is stabilized against thermal decomposition during its recovery from a reaction product mixture by associating with the tetramethyllead from about 20 to about 45 weight percent, based on the total weight of said composition, of a hydrocarbon having a boiling point at atmospheric pressure in the range of from about 90 to about 150 C., said hydrocarbon being selected from the group consisting of alkanes and mononuclear aromatics containing only aromatic unsaturation.
• This hydrocarbon can be a single material such as toluene, isooctane (i.e., 2,2,4-trimethylpentane) or other similar material.
• toluene or isooctane i.e., 2,2,4-trimethylpentane
• thermal stabilizers i.e., thermal stabilizers.
• both of these materials are of considerable value as blending stocks in the finished gasolines for which the tetramethyllead concentrates find their predominant usage.
• Another preferred embodiment of this invention is to use hydrocarbons as above defined which are liquids at room temperature and at least a portion of which boils at or above 110 C. Very desirably only minor portions of such preferred hydrocarbons boil below 110 C.
• thermal stabilizers for the tetramethyllead
• amounts as low as about 3,515,739 Patented June 2, 1970 ice percent give good results in many cases (e.g., when using toluene or isooctane).
• the invention is not intended to be limited to the precise concentration range specified above although it will be understood that marked departures from the foregoing range of the concentrations are undesirable from a number of standpoints including cost effectiveness, ease of processing, and the like. Thus, if the concentration is significantly less than about 15 percent on a weight basis inadequate thermal stability is very likely to be encountered.
• hydrocarbon concentrations ranging from about 20 up to about 45 weight percent are the most suitable for use in accordance with this invention.
• compositions are preferably prepared via the process described in our prior application Ser. No. 809,609, filed Apr. 29, 1959, now U.S. 3,049,558.
• a particular advantage of forming the compositions by conducting that process technique is that the tetramethyllead so-produced is intimately associated with the thermal stabilizer complement from the time that the tetramethyllead is formed. Accordingly, the tetramethyllead is continuously protected against the potential ravages of thermal decomposition not only during its formation but during all subsequent handling and storage operations involving the resultant compositions.
• compositions may, however, be prepared by mixing the appropriate diluent with tetramethyllead formed by other procedures.
• use can be made of conventional tyms of reaction vessels, proportioning pumps, or the like.
• the present thermal stabilizersi.e., the alkanes and mononuclear aromatics containing only aromatic unsaturation as described above are substantially more effective for this purpose than naphthalene and styrene which were among the most effective thermal stabilizers heretofore known for alkyllead antiknock compounds (see U.S. Pats. 2,660,591 through 2,660,596, inclusive).
• the autoclave was charged with monosodium lead alloy flakes in the proportion of approximately 22 pounds per cubic foot of reaction space.
• approxi mately percent by Weight based upon the alloy, of graphite was introduced as a reaction lubricant, plus approximately 0.2 percent of aluminum, as trimethylaluminum.
• Toluene in the proportion of percent of the alloy weight, was introduced.
• the reactor and contents were heated to approximately 80 C., and a feed of liquid methyl chloride was then started at a rate of about 10 parts per minute per 100 parts of alloy charge. Reaction occurred promptly, as shown by a further significant rise in operating temperature.
• the pressure was also allowed to rise to 180 p.s.i.g., and at this time reflux of vapor, principally methyl chloride, was initiated to maintain the pressure at this level.
• the temperature of the reaction mixture was thus controlled in the range of 95 to about 80 C. by variation of the degree of cooling for refluxing purposes.
• the methyl chloride feed was continued until a total of approximately 5 8 parts by Weight per 100 parts by weight of alloy charged had been introduced, this corresponding to approximately 160 percent excess of the theoretical requirement.
• the reaction conditions continued for several hours after termination of the feed, and then the temperature stopped rising and began to drop slightly.
• the excess pressure was vented shortly thereafter and the autoclave contents cooled to approximately ambient temperature.
• the charge was then discharged from the autoclave into ta pool of water in a steam distillation vessel, and the tetramethyllead and toluene were recovered in high yield.
• EXAMPLE II In this operation, substantially the same procedure was employed as in Example I above, except that the sodium lead alloy was charged in the proportions of about 40 pounds per cubic foot of reaction volume.
• the reactor was charged with toluene in the proportions of about 10 parts per 100 parts of the alloy, and trimethylaluminum in proportions providing about 0.2 weight percent aluminum based on the sodium lead alloy.
• the autoclave and contents were heated to about 90 C., and then methyl chloride feed was initiated. Reaction started almost immediately and the pressure rose rapidly, condensation of vapor and reflux being started by condenser cooling at about 130 pounds per square inch pressure. The bulk of the reaction was conducted at a pressure of about 210 pounds per square inch gauge.
• the temperature during the feeding and in the reaction zone was readily controlled in this manner, rising in one short period to about 113 C., but the mean temperature was about 100 C.
• the reacted mixture was discharged from the autoclave to a steam distillaiton operation, and a yield of approximately 70-75 percent of tetramethyllead was obtained, admixed with about weight percent toluene.
• the operation during the entire reaction period was smooth and readily controlled.
• EXAMPLE III In this operation the alloy was charged to an autoclave in proportions of 57 pounds per cubic foot of reaction space.
• a mixture of toluene and methyl aluminum sesquichloride catalyst was charged to the reactor, in the proportions of 10 parts of toluene per 100 parts of alloy and methyl aluminum 4 sesquichloride in the proportions of about 0.8 part based on 100 parts of alloy.
• methyl chloride liquid in the proportions of 94 pounds per 100 parts of alloy was fed at the very start. This charge corresponded to proportions of about 4.3 times the stoichiometric requirements of the reaction.
• the vessel was then heated by circulating hot water at C. through a jacket, while agitating the contents.
• the temperature was raised to about 70 C. and reaction started smoothly and continued without any difliculty of control, until the reaction was essentially complete.
• the temperature of the reaction mixture during this period rose from 70 to 100 C., the mean temperature being 85 C.
• the pressure of operating during the reaction period was maintained at about 205 pounds per square inch gauge.
• the excess pressure was vented and the autoclave charge was cooled by circulating a cooling medium in the jacket.
• the contents were then discharged and subjected to a steam distillation, and a yield of about 70 percent tetramethyllead was obtained, accompanied by toluene in a concentration of about 35 percent.
• EXAMPLE IV The same procedure as employed in Example III above was used in charging the autoclave, except that the meth-- refluxing of liquefied vapors, at about 170 p.s.i.g. Reac-.
• the toluene or other inert hydrocarbon should not be used in proportions significantly above 11 or 12 weight percent of the alloy, in order to be below the preferred upper limit of 50 volume percent of the methyl chloride provided.
• EXAMPLE VI Generally, the same procedure as described in Example I was followed, the loading of the reaction zone or autoclave being about 37 pounds of alloy per cubic foot. :Instead of providing toluene in the proportions of about 10 parts to parts of alloy, however, the concentration was lowered to about only 7 parts per 100 parts of alloy. The catalyst employed was in the proportions of .44 part of trirnethylaluminum per 100 parts of alloy.
• the inert hydrocarbon concentration can be specimen in a closed steel vessel having a wire passing iiivi lfl ioli s iafififi iii? 521355 1523"?
• the upper limit of the amount of iso- 25 fifi%%" ⁇ ' j5; 'gfig 1 5 165 100 50 octane should be reduced, desrrably, to not over about /2 toluene 105 80 5 the liquid volume of the methyl chloride reactant.
• mixtures or foregQmg Shows effect of the Presence Of toluene blends can be employed, and in some cases are preferred, on improving the stability of tetramethyllead. It is seen as shown by the following example. that an increase 1n stability of from 175 to .500, at least,
• One of the particular beneficial efiects of the present invention is the fact that a highly stable system is achieved and maintained. It is found that the inert materials emof Runs A and B was to be over 200 percent as great as the thermal stability of a corresponding composition which contained styrene as the thermal stabilizer. Furthermore, the maximum pressure produced in Runs A and B were far less than that developed in Run C. By the same token the compositions of Runs A and B were vastly superior from the thermal stability standpoint as compared to the composition composed of tetramethyllead and naphthalene used in Run D.
• compositions of Runs A and B had decomposition times that were at least 15 times as long as the decomposition time of the naphthalene-containing composition. Moreover, the maximum pressure developed was far less with the compositions of Runs A and B than it was in the case of the naphthalene-containing composition.
• tetramethyllead in a method of recovering tetramethyllead, the improvement according to which the tetramethyllead is steam distilled While associated with a hydrocarbon have ing a boiling point at atmospheric pressure in the range 1 of from about to about 150 C. in amount sufiicie'nt to stabilize the tetramethyllead against thermal decomposition, said hydrocarbon being selected from the group consisting of alkanes and mononuclear aromatics containing only aromatic unsaturation.
• hydrocarbon is an aromatic type solvent having an initial boiling pointof about C. and a final boiling point of about C.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Lubricants (AREA)

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Citations (2)

• 1962
  • 1962-02-09 DE DE19621420940 patent/DE1420940A1/de active Pending
• 1969
  • 1969-02-06 US US797260A patent/US3515739A/en not_active Expired - Lifetime

Patent Citations (2)

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