RU2185357C1 - Method of synthesis of polyalphaolefins - Google Patents

Abstract

FIELD: organic chemistry, chemical technology. SUBSTANCE: invention relates to the improved method of synthesis of polyalphaolefins that can be used as low-solidifying basic components of lubricant oils. Invention describes a method of synthesis of polyalphaolefins by oligomerization of C₈-C₁₀-alphaolefins in the presence of BF₃ and promoter at increased temperature and pressure. An aqueous 0.5-70-% solution of C₁-C₅-aliphatic alcohol is added as a promoter in amount 0.1-2 wt.% per reaction mixture. Oligomerization is carried out at 10-80 C and under pressure of BF₃ = 0.007-0.7 MPa. Method ensures to synthesized polyalphaolefins with improved combination of viscous-temperature indices. EFFECT: improved method of synthesis, improved properties. 2 cl, 1 tbl, 1 ex

Description

 The invention relates to the field of production of polyalphaolefins, which can be used as low-hardening base components of lubricating oils.

Known methods for producing polyalphaolefins by oligomerization of C ₆ -C ₁₄ alpha olefins in the presence of a BF ₃ catalyst introduced into the reaction mixture without a promoter (US patent 4956513, 1990, cl. 585-525), and with a promoter. As promoters can be used: water (US patent 5210346, 1992, CL 585-10), acetone (US patent 5817899, CL 585-510, 1998), methyl ethyl ketone and other ketones and esters: 2 -ethoxyethanol, 2-butoxyethanol (US patent 4902846, 1990, CL 585-525), 4-hydroxy-4-methyl-2-pentanol (US patent 5420373, CL 585-525, 1995).

The introduction of these promoters into the oligomerization reaction results in the synthesis of mainly alpha-olefin dimers with a yield of 50-80 wt.% Per oligomer, characterized by a low viscosity at 100 ^o C of not more than 1.7 mm ² / s, pour point - minus 63 ^o C.

Closest to the proposed technical solution is a method for producing polyalphaolefins by oligomerization of C ₈ -C ₁₄ alpha olefins at a temperature of 20-50 ^o C and a pressure of BF ₃ from 0.007 to 1.6 MPa. As a promoter, n-butanol is used, which is introduced either in pure form or dissolved in the feed. The amount of promoter introduced is 0.1-0.6% per reaction mixture, the reaction time is up to 3 hours (US patent 4902846, 1990, class 585-525).

However, according to the known method, it is not possible to obtain polyalphaolefins of the required viscosity level at 100 ^{° C.} in high yield, with an improved combination of viscosity-temperature characteristics.

 The objective of the invention is to develop a method for producing polyalphaolefins intended for use as a low-hardening component of base aviation and motor oils with an improved combination of viscosity-temperature properties.

To solve this problem, a method for producing polyalphaolefins by oligomerization of C ₈ -C ₁₀ alpha-olefins in the presence of BF ₃ and 0.5 - 70% aqueous solution of C ₁ -C ₅ aliphatic alcohol as a promoter introduced in an amount of 0.1-2 wt. % per reaction mixture. Moreover, oligomerization is carried out at a temperature of 10-80 ^o With and a pressure of BF ₃ - 0,007-0,7 MPa.

The difference of the proposed method is the use as a promoter of an aqueous solution of aliphatic alcohol C ₁ -C ₅ , which is introduced into the synthesis in the form of 0.5-70 wt.% Concentration in an amount of 0.1-2 wt.% Per reaction mixture.

This difference allows you to get polyalphaolefins with an improved combination of viscosity-temperature characteristics (viscosity at 100 ^o C - 3-4 mm ² / s, at minus 40 ^o C - 2500-3000, pour point - minus 65 ^o C - minus 70 ^o C) .

 The above combination of properties is necessary for the use of these polyalphaolefins as base low-setting components of lubricating oils.

 The essence of the method is illustrated by the following examples.

 Example 1

In the reactor with a stirrer, n-decene-1 is loaded, stirring is turned on, heated to 40 ^{° C.} , BF _{3 is} fed to a system pressure of 0.1 MPa, with these parameters, a 50% aqueous solution of n-butanol in an amount of 0.4 wt. % on alpha-olefin. Stirring of the reaction mixture was continued for 3 hours. Then the mixture is neutralized with a 5% aqueous NaOH solution, sedimented, the aqueous layer is drained, and the hydrocarbon layer is washed three times with water until the acid number in the product is not more than 0.05 mg KOH / 1 g, filtered, the monomer and dimer are distilled off, the residue is hydrogenated to obtain the target product. The quality of the target product is shown in the table.

Polyalphaolefins of similar quality were obtained by the described oligomerization method of n-decene-1, but aliphatic alcohols C ₁ -C ₅ introduced into the synthesis in the amount of 0.8 wt.% Per reaction mass were used as promoters. Their concentration in aqueous solution was 20 wt.%. Oligomerization was carried out in a flow type reactor.

For comparison, a polyalphaolefin was prepared by a known method — oligomerization of n-decene-1 on BF ₃ with the introduction of n-butanol (C ₄ ) dissolved in the feed in an amount of 0.6 wt.% Per reaction mass.

 The characteristics of the obtained polyalphaolefin are given in the table.

 From the data given in the table, it follows that compared with the known method, the proposed method allows to obtain the target product of the required quality with a high yield of 70-75 wt.%.

Claims (2)

1. The method of producing polyalphaolefins by oligomerization of C ₈ -C ₁₀ alpha olefins in the presence of BF ₃ and a promoter at elevated temperature and pressure, characterized in that a 0.5-70% aqueous solution of C ₁ -C ₅ aliphatic alcohol is introduced as a promoter in an amount of 0.1-2 wt. % per reaction mixture. 2. The method according to p. 1, characterized in that the oligomerization is carried out at a temperature of 10 ^o -80 ^o C and a pressure of BF ₃ 0,007-0,7 MPa.

Images