DE889694C - Process for the production of polystyrene derivatives - Google Patents

Description

(WiGBl. P. 175)

ISSUED SEPTEMBER 14, 1953

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is used

The invention relates to the production of polystyrene derivatives, in particular for use are suitable as oil additives.

It is known that the viscosity index of lubricating oils can be increased by the incorporation of small amounts of alkylated polystyrenes can be improved into the same, and a number for this purpose suitable alkylated polystyrenes have already been described. In this way one can obtain suitable products, when condensing polystyrene with propylene polymers, however, various others can Alkylating agents can be used. In general, the condensation of the alkylating agent with the polystyrene are brought about by the action of such catalysts as aluminum chloride; depending on the type of polystyrene used and the precise nature of the alkylating agent, one can use the received a wide variety of products.

Possible alkylating agents include di-isobutylene and other poly-isobutylenes; ao their use is referred to in UK Patent Specification 640,566.

It has now been found that a particularly valuable product can be obtained if one Polystyrene with di-isobutylene or another poly-isobutylene under certain special conditions alkylated, namely in such a way that a polystyrene with an average molecular weight of 20,000 to 150,000 used and a special molar ratio between the poly-isobutylene and the monomeric styrene units in polystyrene, depending on the particular poly-iso used

butylene. In the case of di-isobutylene is this molar ratio (of di-isobutylene to the monomeric styrene units) 0.5: 1 up to 1.25: 1, and the limits in the case of other poly-isobutylenes, z. B. tri-isobutylene correspond to the same weight of poly-isobutylene such as the di-isobutylene weight which these molar ratios represent. With in other words, the amount of poly-isobutylene used is equal in weight to that amount of di-isobutylene, which is derived from the molar ratio of the Di-isobutylene to the monomeric styrene units in the range of 0.5: 1 to 1.25: 1 gives. Under In these circumstances, the product not only has a high degree of efficiency as a viscosity index improver, instead, a high yield is also obtained in the alkylation process.

The polystyrene used preferably has an average molecular weight of 50,000 to 100,000; Particularly good results are obtained with a material with an average molecular weight of about 70,000 achieved. When using di-isobutylene in particular, the above-mentioned molar ratio should preferably not below 0.7: 1; it has been found that ratios from 0.7: 1 to 1: 1 in the alias generally give the best results, in particular this is the case at around 0.75: 1.

In a series of experiments using different molar ratios of the di-isobutylene to the monomeric styrene units, the following results were obtained. The percentage yield reported is the yield of alkylated polystyrene based on the polystyrene originally used and the viscosity index is that of a SAE 10 grade lubricating oil containing 5% of the alkylated polystyrene product. A definition given by McKinney and Warner for such an oil can be found in Leighou's "Chemistry of Engineering Materials" (4th edition); P. 99, edited by the McGraw-Hill Book Co. 40

The alkylation can easily be carried out in such a way that the polystyrene is - ■ dissolves suitable organic solvent, adds a catalyst and then the di-isobutylene or another poly-isobutylene introduces and thereby a maintains a suitable reaction temperature. Typical Friedel-Crafts catalysts are suitable. Aluminum chloride is the most conveniently used catalyst, but also boron trifmoride, zinc chloride and Hydrogen fluoride can be used. It is also useful to use a catalysis modifier, such as z. B. nitrobenzene or aqueous acetic acid, in the Re-. to introduce action. .

In the alkylation of polystyrene by di-isobutylene you got very good results if

Molars Percentage Viscosity relationship yield index 0.5: i 66.2 I08 ..: .. 0.75: ι 73.8 III 0.85: ι 78.2 112 ι: ι 77- ¹ II5

one monochlorobenzene as solvent, aluminum chloride used as a catalyst and aqueous acetic acid as a catalyst modifier. The usage Monochlorobenzene is preferable as a solvent because of its considerable solubility of the alkylated polystyrene product in this solvent. Under such conditions and with Use of a molar ratio of 0.75 as defined above gives very satisfactory results obtain.

It is not necessary to separate the final alkylated polystyrene from the reaction mixture; if desired, it can be derived therefrom by means of a lubricating oil in that described in Example 1 below Way to form a concentrate, which can be mixed with more lubricating oil can to give the desired product of improved viscosity index. A lubricating oil that Class SAE 10 is ideally suited for use in extraction. The concentration of the alkylated Polystyrene in the final lubricating oil to be improved can vary within wide limits, from 0.1 percent by weight up to 5 or 10 percent by weight or even more, which will be appreciated by those skilled in the art will be readily understandable.

The present invention is accomplished by the following Examples illustrated in more detail:

example 1

Polystyrene (50 g) with an average molecular weight of about 70,000 was dissolved in monochlorobenzene (283 g) at room temperature. To the stirring solution was added a mixture of acetic acid (0.25 g) and water (0.13 g). Powdered anhydrous aluminum chloride (4.2 g) was then gradually added over a period of 10 minutes. Then it was allowed in the course of i ^x / ₂ hours with stirring di-isobutylene (40.4 g) run in, keeping the temperature of the reaction mixture to 25 to 30 ⁰ was maintained. Stirring was continued at this temperature for an additional hour.

Concentrated hydrochloric acid (1.67 g of a 32 weight percent solution) was then added; to destroy the activity of the catalyst. The product was stirred for 15 minutes and then treated with a suspension of lime (6.7 g) in SAE 10 lubricating oil (300 g) sufficient to dissolve the alkylated polystyrene. The neutralization was finished ₂ hours by slowly adding a 5o ° / ₀ aqueous solution of sodium hydroxide (4.4 g) with stirring during the course of I ¹ Z, where the temperature was maintained at 25 to 40 ^0th They then added a filter aid (diatomaceous: rde - diatomaceous earth) is added, followed by stirring at 60 to 70 hours ^0th The product was filtered and the monochlorobenzene removed by distillation under reduced pressure until the retort temperature was between 160 and 165 ^° at a pressure of: 0 mm of mercuric acid.

The end product, consisting of a solution of di-isobutylene alkylated polystyrene in lubricating oil SAE 10, remained as a blister residue.

Example 2

Polystyrene with an average molecular weight of 70,000 has been mixed with di-isobutylene in the same way Way as in Example 1 alkylated, except that as a catalyst modifier instead of aqueous Acetic acid nitrobenzene was used. The amounts of reagents used were the same as in Example 1, except that the amount of aluminum chloride was increased to 9.9 g and that 20 g Nitrobenzene was added as a catalyst modifier in place of the aqueous acetic acid.

That from a solution of alkylated with di-isobutylene Polystyrene end product existing in SAE 10 lubricating oil remained similar to the bubble residue Way back.

Example 3

Using the same procedure as in Example 1, polystyrene having an average molecular weight was obtained of 70,000 (50 g) alkylated with tri-isobutylene (40.4 g), with 5.2 g aluminum chloride as Catalyst were used. The other reagents remained the same in amount.

The end product was a solution of tri-isobutylene alkylated polystyrene in SAE 10 lubricating oil.

Example 4

Example 1 was repeated except that no lubricating oil was added when the alkylation was complete became. After neutralization and filtration, the solution of alkylated polystyrene in monochlorobenzene was found added to a large excess of commercial alcohol denatured by methyl alcohol, whereby the alkylated polystyrene was precipitated.

The precipitate was filtered and dried in vacuo.
A non-sticky white powder was obtained.

Example 5

Polystyrene (approx. 94 kg) with an average molecular weight of about 70,000 was converted into monochlorobenzene (approx. 530 kg) dissolved by adding the polystyrene to the monochlorobenzene at a temperature of 20 to 25 ° slowly added over a period of 1 hour.

To the stirred solution yo ° _[0 strength acetic acid (approx. 0.93 kg) followed by powdered anhydrous aluminum chloride (approx. 5 kg) added. Then was allowed during the course of i ¹ ^ hours di-isobutylene (approx. 106 1) run in, the temperature being maintained at 25 to 30 ^0th The mixture was stirred at this temperature for 1 hour and then concentrated hydrochloric acid (approx. 5.7 kg of a solution of 32 percent by weight) was added in order to destroy the activity of the catalyst.

Around 22.7 kg of lime, suspended in around 560 kg of SAE10 lubricating oil, was added to the mixture, thereby partially neutralizing it, and then a 50% solution of sodium hydroxide (approx. 9.1 kg) was added slowly and with stirring during the Added over the course of I ¹ Z ₂ hours at a temperature of up to 40 °.

They then added a filter aid (approx. 13.6 kg diatomaceous earth) is added, followed by stirring for 2 hours at 65 ^0th The product was filtered and the monochlorobenzene removed by distillation.

The final product consisting of a solution of alkylated polystyrene in SAE 10 lubricating oil remained as Bubble residue back.

Claims (3)

PATENT CLAIMS: 1. Process for the production of polystyrene derivatives, characterized by the alkylation of a polystyrene which is an average Molecular weight from 20,000 to 150,000, suitably from 50,000 to 100,000, preferably from has about 70,000, with a poly-isobutylene, z. B. di-isobutylene or tri-isobutylene, the amount of isobutylene used by weight is equal to the amount of di-isobutylene, which is derived from the molar ratio of the di-isobutylene to the monomeric styrene units in the polystyrene in the range of 0.5: 1 to 1.25: 1, expedient from 0.7: ι to 1: 1, preferably from about 0.75: ι would result. 2. The method according to claim 1, characterized in that that the alkylation by dissolving the polystyrene in an organic solvent, z. B. monochlorobenzene, adding a catalyst, e.g. B. aluminum chloride, as well as subsequent Introduce the di-isobutylene or another poly-isobutylene and maintain an appropriate one Reaction temperature is carried out. 3. The method according to claim 1 or 2, characterized in that nitrobenzene or aqueous Acetic acid is present as a catalyst modifier. © 5389 9.