3,197,414 United States Patent Office Patented July 27, 1965 2 fluid compositions containing in all cases a mixture of 3,97,434 TERAETHYLELEAD-TETRAMETHYLLEAD 50 mole percent of tetraethyllead and 50 mole percent ANTEKNOCK FLUDS of tetramethyllead were formulated. In one instance tri James M. Wood, Jr., Baton Rouge, La., assignor to Ethy (methylphosphate was co-present in amount such that the Corporation, New York, N.Y., a corporation of 5 phosphorus to lead atom ratio was 0.8:3. In another Wirginia instance methylcyclopentadienyl manganese tricarbonyl No Brawing. Fied June 26, 1961, Ser. No. 19,294 was present in amount such that the weight ratio of 6 CEainas. (C. 252-386) imanganese to lead was 0.04:1. The illustrative composi tion of this invention contained both the trimethylphos My object is to effectively inhibit redistribution reac 0 phate and the methylcyclopentadienyl manganese tricar tions which occur during storage of certain alkyl lead bonyl ingredients in the proportions just described, the antiknock fluid compositions. resulting antiknock fluid composition having density of Et has been discovered heretofore that certain mixtures 1.473. Each of these formulations was then stored for of alkyllead antiknock agents-e.g. tetraethylhead plus a period of 216 days at ambient conditions (approximate tetramethylead in various proportions-very effectively mean temperature: 26° C.). Periodically the formula improve the antiknock quality of certain modern gaso tions were subjected to standard chemical analyses to lines. However, concentrated antiknock fluid composi determine the extent to which redistribution had occurred. tions composed initially of tetraethylead and tetramethyl This involved the determination of the rate at which tri lead tend to redistribute during storage, even at room ethylmethylead-one of the initial redistribution prod temperatures. The result of such redistribution is the ucts-had been formed once the induction period had formation in the antiknock fluid composition of redis been passed. For this purpose, standardized vapor phase tribution mixtures of tetraalkyllead antiknock compounds chromatographic methods were employed. The results of --e.g. mixtures of tetraethylead, triethylmethyllead, di ethyldimethylead, ethyltrimethyllead and tetramethylead these tests are shown in the table. in various proportions. Such redistributed mixtures are 2; 5 Table.-Rates of redistribution in antiknock oftentimes less desirable as antiknock agents than the fluid mixtures initial mixtures consisting essentially of the tetraethylead and the tetramethyl lead. I have found that trimethylphosphate, a very effec Rate of Redistribution tive and useful antiknock fluid ingredient, e.g. as a pre 30 R Additive Triethyl- Tetra ignition suppressor, an alkyl lead thermal stabilizer in No. methylead methylead formation, consumed, gredient, etc., tends to accelerate the foregoing redis Inole per- wt. per tribution reactions during the storage period. In short, centino.1 centino.

trimethylphosphate acts as a redistribution accelerator. None------0.43 0.86 Hence a need has arisen for an effective means of Trimethylphosphate--- 1.0 2, O overcoming this accelerated redistribution. 3------Methylcyclopentadienyl manganese 0.36 0.72 tricarbonyl. I have found that cyclopentadienyl manganese tricar 4------Trimethylphosphate-methylcyclo- 0.27 0.54 bonyl compounds have the property of effectively com peratadienyl manganese tricar bating the redistribution reactions which would other bonyl. wise occur when tetraethylead-tetramethyllead antiknock fluids containing trimethylphosphate are subjected to stor 1 Relative to the total lead compounds present. age. My invention in part, then, is my discovery that these cyclopentadienyl manganese tricarbonyl compounds it will be noted that the rates of redistribution are ex have a new property and a new use in a new environment. pressed in several ways in the above Table. However, in Provided by this invention is an antiknock fluid com all cases the lower the number the lower the extent of position which consists essentially of redistribution. Accordingly, it will be seen by comparing (1) A mixture of tetraethylead and tetramethyllead, Run 2 with Run 1 that trimethylphosphate tended to sig from about 10 to about 90 mole percent of this mixture nificantly increase the rate of redistribution. However, being tetraethyllead, as seen from Run 4 the presence of a cyclopentadienyl (2) Trimethylphosphate present in amount such that manganese tricarbonyl compound in a trimethylphos the phosphorus to lead atom ratio is from about 0.1:3 to phate-containing antiknock fluid not only effectively Iabout 2:3, and squelched the adverse catalytic effect of the trimethyl (3) A cyclopentadienyl manganese tricarbonyl com phosphate but actually suppressed the redistribution rate pound present in amount such that the weight ratio of to a level below that occurring in any of the other sys manganese to lead is from about 0.005:1 to about 0.5:1. 5 5 tens tested. The cyclopentadienyi manganese tricarbonyl com Very similar results are achieved when using other pounds used in this invention are now well known com compositions of this invention. Examples of these are pounds (see U.S. Patents 2,818,416 and 2,818,417). (I) 10 mole percent of tetraethyl lead plus 90 mole Thus effective use can be made of cyclopentadienyl man percent of tetramethylead, trimethylphosphate (P: Pb ganese tricarbonyl, methylcyclopentadienyl manganese 60 tricarbonyl, ethylcyclopentadienyl manganese tricarbonyl, atom ratio=0.2:3) and methyl-tert-butylcyclopentadienyl tert-butylcyclopentadienyl manganese tricarbonyl, di manganese tricarbonyl (weight ratio, Min:Pb=0.5:1); methylcyclopentadienyl manganese tricarbonyl, indenyl (II) 90 mole percent of tetraethyllead plus 10 mole manganese tricarbonyi, and related compounds in which percent of tetramethylead, trimethylphosphate (P: Pb the cyclopentadienyl hydrocarbon group preferably con 65 atom ratio=1.5:3) and octylcyclopentadienyl manganese tains from 5 to about 17 carbon atoms. From a cost tricarbonyl (weight ratio, Mn:Pb=0.01:1); effectivness standpoint methylcyclopentadienyl manga (III) 20 mole percent of tetraethylead plus 80 mole nese tricarbonyl is particularly preferred. Cyclopenta percent of tetramethyllead, trimethylphosphate (P: Pb dienyl manganese tricarbonyl is also a highly efficient atom ratio=0.4:3) and cyclopentadienyl manganese tri additive for this invention. 70 carbonyi (weight ratio, Min:Pb=0.02: 1); To illustrate the practice and advantages of this inven (iv) 70 mole percent of tetraethylead plus 30 mole tion a series of storage tests was conducted. Antiknock percent of tetramethyllead, trimethylphosphate (P: Pb 3,197,414 3. 4. atom ratio=1:3) and indenyl manganese tricarbonyl 2. The antiknock fluid cornposition of claim a wherein (weight ratio, Mn:Pb=0.1:1); and the like. cyclopentadienyl manganese tricarbonyl compound is The compositions of this invention can contain known methylcyclopentadienyl manganese tricarbonyl. amounts of other additives such as dyes for identification 3. The antiknock fluid composition of claim where purposes, antioxidants (e.g. 2,6-di-tert-butyl phenol, 2,4,6- in Said cyclopentadienyl manganese tricarbonyl corn tri-tert-butyl phenol, 4-methyl-2,6-di-tert-butyl phenol, pound is cyclopentadienyl manganese tricarbonyl. etc.), inert diluents (e.g. kerosene, etc.), rust inhibitors, 4. The antiknock fluid composition of claim where anti-icing additives, metal deactivators, alkyllead thermal in said mixture of tetraethyllead and tetramethyllead is a stabilizers, and the like. Organic halide scavengers can mixture of 50 mole percent of tetraethyllead and 50 mole be used with advantage in the compositions of this in O percent of tetramethylead. vention. For example my compositions can contain such 5. The antiknock fluid composition of claim 1 where scavenger compounds as are described in U.S. Patents in said mixture of tetraethylead and tetramethylead is a 1,592,954; 1,668,022; 2,364,921; 2,398,281; 2,479,900 mixture of 50 mole percent of tetraethylead and 50 mole 903; 2,496,983; 2,661,379; 2,849,302-304; 2,869,993; percent of tetramethyllead and wherein said cyclopenta 2,822,252; etc. The concentrations and proportions of 5 dienyl manganese tricarbonyl compound is methyl cycio such scavengers are well known in the art as witness the pentadienyl manganese tricarbonyl. - foregoing patents. - 6. The antiknock fluid composition of claim where What is claimed is: - in said mixture of tetraethylead and tetramethyllead is a 1. An antiknock fluid composition which consists es mixture of 50 mcle percent of tetraethyllead and 50 mole sentially of 20 percent of tetramethylead and wherein said cyclopenta (1) An alkyllead mixture consisting of tetraethylead dienyl manganese tricarbonyl compound is cyclopenta and tetramethyl lead, from about 10 to about 90 mole dienyl manganese tricarbonyl. percent of this mixture being tetraethylead, (2) Trimethylphosphate present in amount Such that References Cited by the Examiner the phosphorus to lead atom ratio is from about 25 UNITED STATES PATENTS 0.1:3 to about 2:3, and (3) A cyclepentadienyl manganese tricarbonyl com 2,304,883 - 12/42 Campbell ------44-69 pound present in amount such that the weight ratio 2,818,417 12/57 Brown et al. ------44-68 of manganese to lead is from about 0.005:1 to about 3,021,350 2/62 Cook et al. ------260-437 0.5:1. 30 DANIEL E. WYMAN, Primary Examiner.