Terpolymer Alkylated Phenol

This invention relates to phenols alkylated with high molecular weight terpolymers and to the preparation of such alkylated phenols. More particularly this invention relates to phenols alkylated with ethylene-propylene-diene terpolymers which are novel and useful intermediates for the preparation of multifunctional additives for lubricating oils.

The alkylation of phenol with low molecular weight polymers, particularly with homopolymers of C.sub.3 - C.sub.5 olefins, is well known in the art. For example, U.S. Pat. No. 2,398,253 discloses alkylation of phenol with C.sub.8 - C.sub.12 polymers of n-butene in the presence of BF.sub.3 catalyst, with short reaction time, and at a reaction temperature not exceeding about 160.degree. F. The patent further teaches that use of high temperatures, long contact times, and more than equal molar proportions of phenol lead to formation of low molecular weight products and/or dialkyl phenols.

U.S. Pat. No. 2,655,544 discloses the alkylation of phenol with propylene polymer at about 85.degree. to 125.degree. F with 3% BF.sub.3 as catalyst to obtain a yield of about 85% of alkyl phenol having about 21 carbon atoms in the alkyl group. Use of polymers of isobutylene in the alkylation, for example tetraisobutylene, resulted in fragmentation of the polymer, and the princial product obtained was octyl-phenol rather than the expected C.sub.16 alkyl phenol.

British Pat. No. 1,159,368 discloses the alkylation of phenol with C.sub.50 and higher polymers and copolymers of propylene and butylene in the presence of BF.sub.3 catalyst and at a temperature below about 150.degree. F. Yields of alkylated phenol, based on polymer, care substantially below 100% because the double bond required for the alkylation reaction is present in about only 75% of the polymer molecules. In addition, polymer fragmentation during reaction is a problem and is controlled, but not eliminated, by conducting the reaction at temperatures preferably not above about 120.degree. F.

We have now found that phenol can be alkylated with a high molecular weight ethylene-propylene-diene terpolymer to a hydroxylphenyl-substituted terpolymer in essentially quantitative yields based on terpolymer and with essentially no terpolymer fragmentation by treating the terpolymer with about 50 to about 100 moles of phenol for each mole of terpolymer, in the presence of BF.sub.3 as a catalyst in amounts ranging from about 0.05 to about 0.20 moles of BF.sub.3 for each mole of phenol, at a reaction temperature of about 170.degree. to about 300.degree. F and thereafter removing unreacted BF.sub.3 and phenol. The use of diene-containing terpolymer assures that a least one double bond will be present in each polymer molecule and will be available for the alkylation reaction. Thus, under the above-specified reaction conditions each polymer molecule will react with at least one phenol molecule, thereby providing an essentially quantitative yield of alkylation product based on polymer. Preferably, the terpolymers for use in this invention contain multiple olefinic reaction sites, advantageously about 2 to about 5 double bonds for each 1000 carbon atoms in the polymer chain. Suitable terpolymers contain about 35- 65 mole percent propylene, 35- 70 mole percent ethylene, and up to about 10 mole percent of an aliphatic diolefin containing from about 4 to about 25 carbon atoms, for example 1,4-butadiene, 1,3-hexadiene, 1,4-pentadiene, 2-methyl-1,5-hexadiene, 1,7-octadiene, dicyclopentadiene, etc. The preferred terpolymers contain about 35- 45 mole percent propylene, about 65- 55 mole percent ethylene, and about 1.0 to about 2.5 mole percent of 5-alkenyl-2-norbornene, for example 5-ethylidene-2-norbornene, and have number average molecular weights (hereinafter M.sub.n) in the range of about 20,000 to about 25,000. Surprisingly, we have found that with such terpolymers alkylation temperatures as high as 300.degree. F can be employed with no evidence of terpolymer fragmentation.

Preparative methods for suitable ethylene-propylene-diene terpolymers are well known in the art. For example, preparation of an ethylene-propylene-aliphatic diolefin terpolymer, such as ethylene-propylene-hexadiene terpolymer, is taught in U.S. Pat. No. 2,933,480. The preparation of ethylene-propylene-dicyclopentadiene terpolymers is taught in U.S. Pat. No. 3,000,866. The preferred ethylene-propylene- 2-alkenyl-5-norbornene terpolymers, particularly ethylene-propylene- 2-ethylidene-5-norbornene terpolymer, are prepared by copolymerizing ethylene, propylene, and the 2-alkenyl-5-norbornene in tetrachlorethylene solution at a temperature of 20.degree.- 60.degree. C in the presence of catalytically effective amounts of (iso-butyl).sub.3 Al and VOCl.sub.3 as disclosed in U.S. Pat. No. 3,093,620.

The terpolymer alkylated phenols have utility as intermediates in the preparation of various multifunctional addition agents for lubricating oils by methods well known in the art. For example, effective detergent-dispersants can be prepared by sulfurizing the terpolymer alkylated phenol followed by neutralization with a metal oxide or hydroxide to form the metal salt. Advantageously, alkaline earth salts such as barium and calcium salts can be prepared and utilized in this manner.

Alternatively, the terpolymer alkylated phenols can be converted to ashless dispersants by the Mannich Reaction with formaldehyde and a polyamine. For example, terpolymer alkylated phenol, formaldehyde, and a polyamine, such as bis-aminopropyl piperizine, in molar proportions of 1:30:20, react at a temperature in the range of about 120.degree. F to about 300.degree. F to provide a novel ashless dispersant for lubricating oils.

Lubricant addition agents derived from terpolymer alkylated phenols of this invention have the additional benefit of improving the viscosity index of the lubricant since the M.sub.n of the terpolymer is in the range of about 20,000 to about 40,000 which is sufficiently high for viscosity index improving purposes.

The preferred method for alkylating phenol with terpolymer comprises the steps of:

a. dissolving about 5% by weight of terpolymer in a solventextracted SAE 5W lubricating oil by heating the mixture at 300.degree. - 320.degree. F under a blanket of nitrogen,

b. cooling the terpolymer solution to about 180.degree. F and adding rapidly thereto a 100 mole excess of phenol.sup.. BF.sub.3 complex wherein the mole ratio of phenol to BF.sub.3 is about 1:0.1,

c. heating the reaction mixture for two hours at 180.degree.- 200.degree. F, and

d. stripping unreacted phenol and BF.sub.3 by heating the mixture to 440.degree. - 460.degree. F while passing a stream of nitrogen through the reaction mixture.

The data for a number of alkylation runs utilizing an ethylene-propylene- 5-ethylidene-2-norbornene terpolymer having a M.sub.n between about 20,000 and 25,000 dissolved in a solvent-extracted SAE 5W oil having a viscosity at 210.degree. F of 45SSU are listed in Table 1.

The data show that yields, based on terpolymer, in excess of 100% were obtained in the process of this invention. In addition, the viscosity data indicate that no measurable fragmentation of the terpolymer occurred.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it is understood that variations and modifications can be effected within the spirit and scope of the appended claims.