PROCESS FOR PRODUCING ORI CONTROL ADDITIVES

Abstract: An ORI control additive is produced by reacting a polybutenyl succinic anhydride having a molecular weight of 500 to 10,000 with a polyoxyalkylene diamine. The anhydride and diamine are reacted at a temperature from 163 to 191°C, the infra red absorbancy of the reaction mixture is monitored, (preferably at 1705 cm⁻¹), and the reaction is stopped when the absorbancies are equivalent at two successive time periods.

Description: This invention relates to a method of producing an octane requirement increase (ORI) control additive for motor fuels such as gasoline. More particularly, it relates to an improved method of producing an ORI control additive. Modern internal combustion engines are designed to operate using a non-leaded gasoline as fuel. Some engines will, although initial operation on the design fuel was satisfactory, after a period of time develop a propensity to "knock" under load. As the problem increases in severity, the engine can continue to fire erratically after the ignition has been shut off, a behavior referred to as "dieseling". This reduced driveability can sometimes be corrected by adjusting ignition timing but may require the operator to switch to a higher octane fuel. The phenomenon observed is thus referred to as octane requirement increase (ORI). There have been additives produced which control the ORI and provide the ORI control necessary in fuels of lower octane. However, the process by which the ORI control additives have been made is more costly and requires excessive time to provide the desired ORI control additive. Thus, it is an object of the present invention to provide a means of producing these ORI control additives at less cost and in significantly less time while having a greater yield of product (i.e., ORI control additive). U. S. Patent 4,053,743 discloses a method for controlling the pH and other concentration variables of a controlled feed component, wherein when at least one desired outlet concentration or a function dependent on outlet concentration is given, initially the apparent output concentration of at least one other feed component is calculated with the aid of the inlet concentration and the residence time distribution of the controlled feed component from the inlet to the outlet flow thereof. Co-assigned U.S.-A-5 061 291 discloses a method for producing a motor fuel composition which inhibits engine ORI and intake valve deposit formation therein. European Application 90302384.4 discloses a method of predetermining the exact weight ratio of the reactants to produce a product and maintain the weight ratio of the reactants to obtain a maximum yield of the product. This invention provides an improvement in a method of producing an ORI control additive which is the reaction product of a polyoxyalkylene diamine and an alkenyl-succinic anhydride. The improvement comprises reacting solvent free the anhydride and diamine at a temperature ranging from 163°C (325°F) to 191°C (375°F) and monitoring the absorbances of the reaction product by infrared spectroscopy to determine the degree of reaction completion, whereby when the absorbances are equivalent in two successive time periods, the reaction is stopped/completed and the reaction product withdrawn. The reaction product produced according to this invention is a bis-succinimide of a polyoxyalkylene diamine. The present improvement in a method of preparing an ORI additive has been developed to facilitate and ease the production of an ORI control additive. The preparation of a composition useful in controlling ORI was disclosed in copending U.S.-A-5 061 291 In the present invention there is disclosed an improved procedure for the preparation of the composition. The processing improvement consists of eliminating the use of a solvent for the reaction, operating at an increased temperature and determining the degree of completion of the reaction using infrared spectroscopy. The advantages resulting from the application of this improvement include: 1) shortening of reaction time while permitting a higher batch yield, thus improving the economics of the operation; 2) reduction of the possibility of atmospheric hydrocarbon emissions during preparation of the composition as no hydrocarbon is refluxed; and 3) higher selectivity for the formation of the desired product. According to the present invention, an improvement is provided in a method of producing an ORI control additive which is the reaction product of a polybutenyl succinic anhydride having a molecular weight of 500-10,000 and a polyoxyalkylene diamine. The improvement comprising reacting solvent free anhydride and diamine at a temperature ranging from 163°C (325°F) to 191°C (375°F) and monitoring the absorbances of the reaction product by infrared spectroscopy to determine the degree of reaction completion, whereby when the absorbances are equivalent in two successive time periods, the reaction is stopped/completed and the reaction product withdrawn. In the method the preferred temperature at which the reaction takes place is about 177°C (350°F) The absorbance of the reaction product is measured at 1705cm⁻¹ according to the process described below in Table I. In the method set forth in Table I below, the absorbance of the imide carbonyl of the reaction product is periodically measured at 1705 cm⁻¹. The reaction product is a bis-succimide of a polyoxyalkylene diamine, and the reaction time of producing the reaction product is 5.0 to 12.0 hours. The advantages of operation using the present improvements can best be demonstrated by use of comparative examples as provided below. Preparation of the ORI controlling composition according to a procedure such as those discussed in the above cited references, especially in U.S.-A-5 061 291 is described below in Example A. Operation of the improved process of the present invention is described in Example B. In Examples A and B, the completeness of the conversion being effected was determined by monitoring the absorbance of the infrared peak occurring at 1705 cm⁻¹. The procedure for this is as set forth above in Table I. The reaction was considered to be complete when two consecutive hourly samples exhibited equivalent absorbances when measured using the spectroscopic method of Table I. EXAMPLE A A ten gallon stainless steel reactor equipped with a motor driven turbine agitator, a ring sparger for gas delivery, a heating jacket and a cooled condenser for condensation of overhead vapors was charged with a mixture of mixed xylenes (50 parts by weight), a polyoxyalkylene diamine exhibiting an effective molecular weight of 3402, as calculated from a total base number determined using ASTM D2896 (21.3 parts by weight), and a polyisobutenylsuccinic anhydride having a molecular weight of 2123 (28.7 parts by weight). The stirrer was started and nitrogen introduced through the sparger at a rate of 75.4 std H/m³ (1.06 SCFH/gallon). The mixture was heated under total reflux and samples periodically withdrawn and their infrared spectra taken. The results of these analyses are presented below in Table III. The absorbance at 1705 cm⁻¹ was still increasing slowly after 10 hours at reflux, at which time external application of heat was stopped and the product withdrawn from the reactor through a cartridge filter. EXAMPLE B A ten gallon reactor as described in Example A; above, was charged sequentially with a polyoxyalkylene diamine exhibiting an effective molecular weight of 3402, as calculated from a total base number determined using ASTM D2896 (42.5 parts by weight), and a polyisobutenylsuccini anhydride having a molecular weight of 2123 (57.5 parts by weight). The stirrer was started and nitrogen introduced through the sparger at a rate of 75.4 std m³/H (1.06 SCFH/gallon). Heat was applied and the reaction mass brought to a temperature of 177°C (350°F). Samples were periodically withdrawn and their infrared spectra taken. The results of these analyses are presented below in Table IV. Reaction was judged complete after 8 hours at 177°C (350°F), at which time external application of heat was stopped. The product was withdrawn from the reactor through a cartridge filter. Below, in Table II, the process for making the infrared analysis is set forth. The results i.e., infrared spectra, of (1) the mixture of Example A under total reflux, and (2) the samples of Example B heated to 177°C (350°F) are, respectively, provided below in Table III and Table IV. In the process of preparing for commercialization, larger batches were made in a 1892 litre (500 gallon) reactor equipped with a motor driven turbine agitator, a ring sparger or gas delivery, a heating jacket and a cooled condenser for condensation of overhead vapors. A summary of these preparations is given below in Table V. The infrared spectrophotometric analysis technique (Table II, above) used to monitor the reaction was slightly different. The comparison of these results shows a significant advantage for using the present process. These larger scale batches dramatically demonstrate the advantage of using our improvement in reaction time required to prepare the ORI suppressant. Use of the improved procedure does not compromise the effectiveness of the product. Suppressants made using the technology disclosed in U.S-A-5 061 291 (i.e. such as in Examples A and C, above) and the improved process (i.e., as in Examples B and D above) both result in an octane requirement increase of ca 5 octane numbers at a dose of 30 PTB. In comparison, testing of a fuel blended without the suppressant results in an octane requirement increase of 10 or more octane numbers.

Claims: A method of producing an ORI control additive by reacting a polybutenyl succinic anhydride having a molecular weight of 500 to 10,000 with a polyoxyalkylene diamine, characterized by reacting in the absence of a solvent the anhydride and diamine at a temperature from 163 to 191°C monitoring the infra red absorbance of the reaction mixture, and stopping the reaction when the absorbances are equivalent at two successive time periods. A method according to Claim 1 characterized in that the temperature is about 177°C. A method according to Claim 1 or 2 characterized in that the absorbance is measured at 1705 cm⁻¹. A method according to any one of Claims 1 to 3 characterized in that the reaction time is 5.0 to 12.0 hours.

Inventors: ERICKSON, ROBERT WOODROW, LEONG, MARIAN FAY, MATTHEWS, LEONARD-ANTHONY, POWERS, WILLIAM JOSEPH POWERS III
Applicants: TEXACO DEVELOPMENT CORPORATION
Application year: 1990
Main classification: C10L1
IPC codes: C10L1, C08F8