JPS6027655B2 - Method for producing esters of hydrocarbon-substituted succinic anhydrides - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for producing esters of hydrocarbon-substituted succinic anhydrides and to the esters so produced.

Esters of hydrocarbon-substituted succinic anhydrides are known products and are useful for many purposes, for example as dispersing additives for lubricating oils (UK No. 981,850), UK No. 10
55337 and US 3,576,743).

Particularly useful esters are those made by reacting a hydrocarbon-substituted succinic anhydride with pentaerythritol. The reaction product is usually a complex mixture of polyesters. The general manufacturing method of these estels is
It is described in UK No. 1055 Spot No. 7. This general method involves esterification of a hydrocarbon-substituted succinic anhydride with pentaerythritol at elevated temperatures. Water vapor is produced during the reaction and is removed from the reaction zone as the reaction progresses. A solvent may be used in the method to facilitate removal of water vapor from the reaction mixture. Additionally, removal of water vapor can be facilitated by passing an inert gas such as nitrogen through the reaction mixture (see US 3,576,743). In all known methods of esterifying hydrocarbon-substituted succinic anhydrides with pentaerythritol, the water of esterification is removed from the reaction zone as the reaction proceeds.

This is an obvious desire since the esterification reaction is an equilibrium reaction, and removal of water is believed to be necessary to obtain satisfactory conversion of the hydrocarbon-substituted succinic anhydride. A problem associated with water removal is that some of the ventaerithritol is picked up overhead along with the steam.

Thus, venting such vapors into the atmosphere is environmentally unacceptable. Instead, the reaction vessel is equipped with a condenser to condense water vapor and solvent vapor (if a solvent is used). However, the cooling required to condense such vapors may cause the pentaerythrite present in the vapor to sublimate on various parts of the reactor equipment, such as the top of the reaction vessel, overhead tubes, and condenser. It turns out. Pentaerythritol, which has a melting point of about 2600°, is deposited as such or as its polycondensate. This fouling of the reactor equipment is highly undesirable since periodic cleaning is required. Surprisingly, we have found and presented that the reaction of hydrocarbon-substituted succinic anhydride with pentaerythritol can be carried out in a closed reaction vessel, which substantially overcomes the drawbacks of the above-mentioned known processes. .

This discovery shows that esterification water is transferred from the reaction zone during the reaction process.
This is considered surprising since it has been found that removal of hydrocarbon-substituted succinic anhydrides is unnecessary to achieve satisfactory conversion.

Therefore, vapor condensation is no longer necessary during the reaction process, which means that the amount of bentaerythritol sublimated is substantially reduced. A further surprising finding is that the pressure build-up inside a closed container is quite low, i.e. typically 5 or 6
This is based on the rationale that the pressure build-up is not expected to be too high for a glass or glass-lined closed reaction vessel, and that the reaction is carried out in such a vessel. It means to get. Glass or glass-lined closed reaction vessels are desirable because the reactants and certain by-products are acidic. Accordingly, the present invention provides a method for producing an ester of a hydrocarbon-substituted succinic anhydride and pentaerythritol, which comprises reacting the hydrocarbon-substituted succinic anhydride and pentayrytrit. The above-mentioned method is characterized in that it is carried out in a reaction vessel.
The hydrocarbon-substituted succinic anhydride from which the ester is produced is a known product and can be represented by the general formula below.

where R is an alkyl or alkenyl group having from 30 to 700, suitably from 50 to 400, preferably from 50 to 20 carbon atoms.

The hydrocarbon substituents may contain non-hydrocarbon groups such as chloro or bromo groups, provided that such groups are not present in a sufficiently large amount to alter the hydrocarbon nature of the substituent. The anhydride is prepared by reacting an olefin, such as a C2 to C5 olefin polymer, such as polybutylene, polyisobutylene or polypropylene, or a chloride thereof, with maleic anhydride.
Alternatively, it may be prepared by known techniques, such as by contacting a mixture of the polymer and maleic anhydride with chlorine. A preferred method involves contacting a mixture of the olefin polymer and maleic anhydride with a molar deficit of chlorine based on the maleic anhydride. The anhydride produced from chloride or using chlorine is
They usually contain small amounts of residual chloro groups and are particularly corrosive since hydrogen chloride is formed during the reaction. Instead of the anhydride, the corresponding succinic acid can be placed in the reaction vessel. Such acids are easily dehydrated to form anhydrides at temperatures above 100° C. and then esterified with pentafluorite. The molar ratio of pentaerythritol to hydrocarbon-substituted succinic anhydride used in the present invention can vary within a wide range.

Suitably, the molar ratio of bentaerytrit to hydrocarbon-substituted succinic anhydride is from 0.25:1 to 4:1.
Preferably 0.5:1 and 3.0:1. Commercially obtained pentaerythritol may contain up to 10% w diventaerythritol. The reaction temperature may also vary within a wide range, and reaction temperatures from 140 to 2590 degrees Celsius are suitable, and 170 to 230 degrees Celsius are preferred. The reaction time may also vary within a wide range, and reaction times of 2 to 4 glue hours are suitable. A solvent may also be present in the reaction mixture. Examples of solvents include hydrocarbons such as xylene, toluene and key oil, ethers such as diphenyl ether, ketones and chlorobenzene. An esterification catalyst may also be added. As previously described, the reaction is carried out in a closed reaction vessel.

The term "closed reaction vessel" is well understood by those skilled in the art, and as far as the present invention is concerned, means that substantially no steam, particularly water vapor, produced during the reaction is removed from the reaction zone during the course of the reaction. Such vapors are thus neither vented nor liberated by condensation during the reaction process. Therefore, the only water present in the reaction zone is substantially that dissolved in the reaction mixture and that present in the vapor phase. Therefore, there is no need to cool any part of the reaction vessel during the reaction process, and substantially the reaction vessel can be thermally insulated, which means that the internal temperature of the reaction vessel is substantially the same as the temperature of the reaction mixture. It means that. Since the interior of the reaction vessel has no communication with the outside atmosphere, automatic pressure build-up occurs. Suitably between 40 and 85% of the volume of the closed reactor is filled with the reaction mixture. At the end of the reaction, ie, when the desired conversion of anhydride has been achieved, the closed reaction vessel is opened and water vapor containing no or substantially no pentaerythritol is vented. The reaction product obtained by the process of the invention may be worked up by conventional techniques such as centrifugation or filtration and washing.

The esters are used in a variety of applications, but are particularly suitable as additives to fuels and crude oils, including oil additives such as gasoline and medium distillate fuels.

The esters are particularly suitable as additives in lubricating oils such as mineral lubricating oils. The invention will be described in connection with the following examples.

In the example, polyisobutylene substituted succinic anhydride was obtained by passing chlorine through a mixture of polyisobutylene (MWIOOO) and maleic anhydride. Example 1 (comparison) In a 1 liter open gas reaction vessel, 500 molar polyisobutylene-substituted succinic anhydride (acid value 1.63 meqK) was added.
OH/water), 112 pentaerythritol (molar ratio of pentaerythritol to anhydride 2:1) and 37
Add xylene in the evening.

This mixture was esterified at a temperature of 20,000°C for two hours. The water of esterification was continuously removed with xylene acting as a water transport agent. The water was supplied using a Dean and Stark apparatus.
separated from xylene by The reaction product was cooled to ambient temperature, diluted with an equal volume of gasoline, and unconverted pentaerythritol was removed by centrifugation. The anhydride conversion was 96% w based on the amount of anhydride placed in the reaction vessel (product acid number 0.06 meq KOH/polymer). During the reaction, bentaerythritol sublimated onto the top of the reaction vessel and onto the overhead system.
The amount of sublimed material was measured and found to be 4% w based on the amount of pentaerythritol placed in the reaction vessel. Example 2 In a 2 liter sealed stainless steel autoclave, 81
Polyisobutylene-substituted succinic anhydride (acid value 16)
3 heq KOH/night) and 184 heq. pentaerythritol (molar ratio of pentaerythritol to anhydride: 2:
1) (approximately 6% cough volume).

This mixture was esterified for 2 hours at 200% overflow, after which the autoclave was opened, the reaction product was cooled to ambient temperature, diluted with an equal volume of gasoline and the unconverted pentane The erythritol was removed by centrifugation. During the esterification reaction, the pressure build-up was approximately 4 bar (
The theoretical pressure build-up is about 15 degrees, which is 200q0
is the vapor pressure of water at Anhydride conversion is 90%
It was found that the acid value of the product was 0.1 heqKOH'. The amount of substance sublimated to the top of the reaction vessel is
was measured and found to be less than 0.1% w based on the amount of pentaerythritol placed in the reaction vessel.
Example 3 Example 2 was repeated using a glass-lined autoclave, a molar ratio of bentaerythritol to anhydride of 1.3:1, and a reaction time of 9 hours.

Substantially the same results as Example 2 were obtained, except that no sublimed material was observed in the reactor at the end of the reaction. Example 4 Example 3 was repeated using a molar ratio of bentaerythritol to anhydride of 1.3:1, a reaction temperature of 220° C., and a reaction time of 1 hour.

Claims (1)

[Scope of Claims] 1. A method for producing an ester of hydrocarbon-substituted succinic anhydride and pentaerythritol, which comprises reacting a hydrocarbon-substituted succinic anhydride with pentaerythritol, wherein the reaction is a closed reaction. The above method, characterized in that it is carried out in a container. 2. A patent claim characterized in that the anhydride has a general formula ▲A mathematical formula, a chemical formula, a table, etc.▼ [wherein R is an alkyl or alkenyl group having 50 to 200 carbon atoms] The method described in Scope 1. 3 The molar ratio of pentaerythritol to anhydride is 0
．． Claim 1 from 025:1 to 4.0:1
Or the method described in 2. 4. The method according to any one of claims 1 to 3, wherein the reaction temperature is 140 to 255°C.