CN103145553B - The Synthesis and application of 2,3-Hydrocarbyl-substituted succinic acid diesters - Google Patents

Abstract

The present invention relates to the Synthesis and application of 2,3-Hydrocarbyl-substituted succinic acid diesters. At low temperatures, carboxylicesters and highly basic LDA react and form enolate, and tetracol phenixin oxidative coupling prepares 2,3-dialkyl succinic acid diester. Adopting liquid nitrogen to lead to the novel method directly freezed into reaction system, liquid nitrogen has shielding gas and refrigeration two kinds of functions. Direct method of cooling has temperature of reaction energy-conservation, easy to control, substitutes the advantage of inert protective gas. 2,3-Hydrocarbyl-substituted succinic acid diesters can be used as the electron donor of polypropylene catalyst.

Description

Synthesis and application of 2,3-hydrocarbyl substituted succinic acid diesters

technical field

The invention belongs to the field of organic synthesis research and relates to a method for synthesizing organic compounds, in particular to the synthesis of 2,3-hydrocarbyl substituted succinic acid diesters and the preparation of 2,3-hydrocarbyl substituted succinic acid diesters synthesized by the method in the preparation of polypropylene catalysts application.

Background technique

Ziegler-Natta catalysts are the mainstream catalysts for industrial polypropylene catalysts and are widely used. Usually, organic bases are added as internal electron donors during the preparation of Ziegler-Natta catalysts; bases are added as external electron donors during the polymerization of propylene. The electron donor can significantly improve the performance of the catalyst, such as improving the activity of the catalyst, improving the isotacticity of polypropylene, improving the bulk density of the polymer, improving the relative molecular mass and relative molecular mass distribution of the polymer, etc. Searching for ideal internal electron donor compounds has always been a hotspot in the research of Ziegler-Natta catalysts. The existing patent CN00801123 and other patents disclose that succinate compounds are used as electron donors of catalysts, and their application to propylene polymerization has the following advantages. 1) Low catalyst cost, 2) High catalyst activity and polypropylene isotacticity, 3) Wide molecular weight distribution of polypropylene, 4) It can be used as an internal electron donor or an external electron donor, 5) It can be used as an internal electron donor When used as a body, it can be used alone, and can be used in combination with other internal electron donors to change the performance of the catalyst. 6) Polypropylene products have high impact resistance and flexural modulus.

In literature reports, the synthesis methods of 2,3-hydrocarbyl substituted succinic acid diesters include: esterification, electrolysis, condensation, oxidative coupling, etc. In the article of ActaChem.Scand.13 (1959) 40-49, EbersonL has prepared 2,3-hydrocarbyl substituted succinic acid diesters with electrolytic method, and the electrolytic condition of this method is selected is harsh, and the productive rate of target product is relatively low, only Limited to laboratory research, it is difficult to form industrialized production. U.S. Patent US20030181743A1 discloses a synthetic method. Under the action of a strong base, succinic acid diester is condensed with ketone or aldehyde to obtain 2,3-diene-based succinic acid diester. This route has many reaction steps and low yield , the post-processing is complicated. In the article of Russian Chemical Bulletin, International Edition, 58 (2009) 1672-1680, ALLyubimtsev selected isovaleric acid as a raw material, treated with LDA, oxidatively coupled to generate 2,3-dihydrocarbyl succinic acid, and then obtained by esterification 2,3-Dialkyl succinic acid diester, this route consumes more LDA, the synthesis route is long, and the operation process is complicated. Chinese patent CN200910077778.1 discloses that α-cyano-substituted esters are used as raw materials, and 2,3-dihydrocarbyl-2,3-dicyanosuccinates are generated by oxidative coupling with iodine, followed by hydrolysis and decarboxylation reactions 2,3-Dialkyl succinic acid is obtained, and then esterified to obtain a succinic acid diester. The raw materials used in this reaction route are not easy to obtain, the reaction route is long and has many steps, and the yield is low. IwaoOjima, in the Chemistryletters, 1992, 1592-1594 article, selected 2-hydrocarbyl acetate as a raw material, and obtained 2,3-dihydrocarbyl succinic acid diester through TiCl ₄ oxidative coupling. CN1313869A outlines various synthetic methods available for 2,3-dihydrocarbylsuccinic acid diesters. Among them, the route of using 2-hydrocarbyl acetate as a raw material and using TiCl ₄ as an oxidative coupling agent is relatively simple, and is more suitable for the preparation of 2,3-hydrocarbyl substituted succinic acid diesters. However, the reaction requires a temperature of -78°C, and the reaction system is cooled by an indirect coolant of a slurry mixture of liquid nitrogen and organic matter such as ethanol or acetone. The disadvantage is that the reaction temperature is not easy to adjust, wastes energy, and is difficult to realize industrial production. The invention innovatively uses liquid nitrogen to flow into the reactor to directly cool the reactants, so as to solve the refrigeration problem and realize industrial production.

Contents of the invention

The purpose of the present invention is to provide a synthesis method for directly cooling the reaction system of 2,3-hydrocarbyl substituted succinic acid diester compound, so as to solve the problem that the low temperature conditions in the synthesis process are not easy to control, thus making industrial production difficult.

To achieve the above object, the present invention adopts the following technical solutions:

A method for preparing a 2,3-hydrocarbyl substituted succinic acid diester compound having the structure of general formula I, comprising the process of reacting a carboxylate with a strong base in a solvent to form an enol metal salt and then oxidatively coupling it with an oxidant, It also includes passing liquid nitrogen into the reactor to directly cool the reaction liquid so that the reaction temperature is -100°C to 25°C; the liquid nitrogen can be used as an inert protective gas after gasification during the reaction. The carboxylate used in the method is at least one of the carboxylate with general structural formula II;

in,

R ₁ and R ₂ are each independently selected from H or a C ₁ -C ₂₀ hydrocarbon group, and the hydrocarbon group is a straight chain hydrocarbon group, a branched chain hydrocarbon group, a cyclohydrocarbyl group, a chain hydrocarbon group, a cyclohydrocarbyl group, a cyclohydrocarbyl chain hydrocarbon group, an aryl group, or a chain hydrocarbon group Aryl, aryl chain hydrocarbon group; the 2,3-hydrocarbyl substituted succinic acid diester synthesized therefrom is 2,3-unsubstituted succinic acid diester, 2,3-one hydrocarbon substituted succinic acid diester, 2,3- Dihydrocarbyl substituted succinic acid diester, 2,3-trihydrocarbyl substituted succinic acid diester and 2,3-tetrahydrocarbyl substituted succinic acid diester.

R ₃ is selected from C ₁ -C ₂₀ hydrocarbon groups, and the hydrocarbon groups are straight-chain hydrocarbon groups, branched-chain hydrocarbon groups, cyclic hydrocarbon groups, chain hydrocarbon groups, cyclohydrocarbyl groups, cyclohydrocarbyl chain hydrocarbon groups, aryl groups, chain hydrocarbon aryl groups, and aryl chain hydrocarbon groups.

When the carboxylic acid esters are different esters for cross-coupling, the two R ₁ , two R ₂ , and two R ₃ in the synthesized 2,3-hydrocarbyl substituted succinic acid diester structure are the same or different, and R ₁ and _R2 may be the same or different.

In the method provided by the present invention, in a preferred solution, each of R ₁ and R ₂ is independently selected from H or a C ₁ -C ₁₀ hydrocarbon group, and the hydrocarbon group is a straight chain hydrocarbon group, a branched chain hydrocarbon group, a cyclic hydrocarbon group, or a chain hydrocarbon group Cyclic hydrocarbyl, cyclohydrocarbyl chain hydrocarbyl, aryl, chain hydrocarbyl aryl, aryl chain hydrocarbyl; _R3 is selected from C ₁ ~C ₁₀ hydrocarbyl, said hydrocarbyl is straight chain hydrocarbyl, branched chain hydrocarbyl, cyclohydrocarbyl, chain hydrocarbyl Cyclohydrocarbyl, cyclohydrocarbylalkanyl, aryl, alkanylaryl, arylalkanyl. From the viewpoint of ecology and environmental protection, when R ₁ , R ₂ , and R ₃ are hydrocarbon groups, the hydrocarbon groups of C ₁ -C ₁₀ are preferably straight chain hydrocarbon groups, branched chain hydrocarbon groups, cyclohydrocarbyl groups, chain hydrocarbon groups, cyclohydrocarbyl groups, and cyclohydrocarbyl chain hydrocarbon groups.

Further, the carboxylate having the general structural formula II is selected from ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, 2-ethylhexyl acetate, ethyl propionate, Propyl propionate, isopropyl propionate, butyl propionate, isobutyl propionate, 2-ethylhexyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, isopropyl butyrate Esters, Butyl Butyrate, Isobutyl Butyrate, Amyl Butyrate, Isoamyl Butyrate, 2-Ethylhexyl Butyrate, Ethyl Isobutyrate, Propyl Isobutyrate, Isopropyl Isobutyrate ester, butyl isobutyrate, isobutyl isobutyrate, 2-ethylhexyl isobutyrate, ethyl valerate, propyl valerate, isopropyl valerate, butyl valerate, isobutyl valerate Ester, Isopentyl Isovalerate, Ethyl Isovalerate, Propyl Isovalerate, Isopropyl Isovalerate, Butyl Isovalerate, Isobutyl Isovalerate, Isoamyl Isovalerate, Ethyl Caproate ester, propyl caproate, isopropyl caproate, butyl caproate, isobutyl caproate, 2-ethylhexyl caproate, ethyl isocaproate, isopropyl isocaproate, butyl isocaproate, isohexane Isobutyl Acetate, Ethyl 3-Methylhexanoate, Butyl 3-Methylhexanoate, Isobutyl 3-Methylhexanoate, Ethyl 2-Ethylhexanoate, Propyl 2-Ethylhexanoate , Isopropyl 2-ethylhexanoate, Butyl 2-ethylhexanoate, Isobutyl 2-ethylhexanoate, Ethyl phenylacetate, Propyl phenylacetate, Isopropyl phenylacetate, Butyl phenylacetate , Isobutyl phenylacetate, ethyl naphthalene acetate, propyl naphthalene acetate, isopropyl naphthalene acetate, butyl naphthalene acetate, isobutyl naphthalene acetate, methyl cyclohexyl acetate, ethyl cyclohexyl acetate, propyl cyclohexyl acetate Esters, Isopropyl cyclohexyl acetate, Butyl cyclohexyl acetate, Isobutyl cyclohexyl acetate, Methyl cyclopentyl acetate, Ethyl cyclopentyl acetate, Propyl cyclopentyl acetate, Isopropyl cyclopentyl acetate , Butyl cyclopentyl acetate, Isobutyl cyclopentyl acetate, etc.

In the method provided by the invention, the strong base is an organometallic compound, including potassium alkoxide, sodium alkoxide, lithium alkoxide, lithium amide, sodium amide, and potassium amide. Compounds preferably selected from the group consisting of potassium methoxide, potassium ethoxide, potassium propoxide, potassium butoxide, potassium isobutoxide, potassium tert-butoxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, sodium isobutoxide, tert Sodium Butylate, Lithium Diethylamide, Lithium Dipropylamide, Lithium Diisopropylamide (LDA), Lithium Dibutylamide, Lithium Diisobutylamide, Sodium Amide, Potassium Amide. Considering the convenience and safety of use, lithium diisopropylamide (LDA) was chosen. The strong base used in the method of the present invention can be its pure substance, or the reaction mixture obtained when preparing the strong base.

In the method provided by the invention, the solvent is an aprotic solvent with a low melting point; the aprotic solvent with a low melting point is selected from one or more of ethers, nitriles, halogenated hydrocarbons, aromatic hydrocarbons, paraffins, and naphthenes mixture of species. The aprotic solvent is further selected from ether, isopropyl ether, 1,2-dimethoxyethane, tetrahydrofuran, acetonitrile, methylene chloride, ethylene dichloride, toluene, ethylbenzene, pentane, hexane, A mixture of one or more of heptane, cyclopentane, methylcyclopentane, methylcyclohexane, and dimethylcyclohexane.

In the method provided by the present invention, the oxidant is an oxidized transition metal compound, such as titanium tetrachloride.

In the method provided by the invention, carboxylate:strong base:oxidant can be selected in a wide range, preferably 1:1~5:1~5; reaction temperature -100~20°C, preferably -90~-20°C . The present invention prepares the reaction of 2,3-hydrocarbyl substituted succinic acid diester, the initial concentration of each raw material can be carried out in a very wide range, and the concentration of carboxylate is generally preferred to be 0.05-10M, and the concentration of strong base is 0.05-10M , the concentration of the oxidizing agent is 0.05-10M.

In the prior art, the synthesis of 2,3-hydrocarbyl substituted succinic acid diester needs to be carried out under low temperature conditions, and the indirect cooling method with complex operation and difficult industrialization is adopted. And the realization of the low temperature condition of the method of the present invention is to use the liquid nitrogen which is inert to the chemical reaction as a refrigerant, and the liquid nitrogen is directly passed into the reactor to directly cool the reaction liquid to reach the low temperature condition required for the reaction. The reaction temperature is easy to control, and at the same time Energy is saved, and industrial production is easily realized; the liquid nitrogen directly fed into the reaction system in the present invention can also be used as an inert protective gas after vaporization, replacing other inert protective gases, reducing operating costs, simplifying the reaction device, and simplifying the operation. The method for preparing 2,3-hydrocarbyl substituted succinic acid diester of the present invention does not require separation and purification of the intermediate product enolate, and can directly add an oxidant to carry out the next step of oxidative coupling reaction, and has the advantages of simplified operation, simple reaction device, and the like. In addition, because olefin polymerization catalysts often require two or more internal electron donors to make the catalyst have new properties, starting from the 2,3-hydrocarbyl substituted succinic acid diester compound as the electron donor of olefin polymerization catalysts, it is possible to use Mixtures of different 2,3-hydrocarbyl substituted succinic acid diesters as electron donors. The method provided by the invention can adopt the cross-oxidative coupling of two or more carboxylates with different structures, and the obtained product is a mixture of different 2,3-hydrocarbyl substituted succinates, which can meet the requirements of olefin polymerization catalysts for different electron donors. need. The method of the present invention can directly synthesize compounds containing different 2,3-hydrocarbyl substituted succinates, such as when a single fatty acid ester is used for oxidative coupling to obtain 2,3-non-hydrocarbyl substituted succinates, or 2,3-identical Dihydrocarbyl substituted succinates, or 2,3-identical tetrahydrocarbyl substituted succinates; when two fatty acid esters are used for oxidative coupling, 2,3-monohydrocarbyl substituted succinates and/or 2, 3-trihydrocarbyl substituted succinates (three different hydrocarbyl groups), even two _R3 can be different from each other. Since the hydrocarbon groups in the structure of the general formula I are the same or different, it is of great significance for the synthesis of olefin polymerization catalysts; a method for synthesizing succinic acid esters with various structures is very useful for industrial production. Therefore, another object of the present invention is to use the 2,3-hydrocarbyl substituted succinic acid diester prepared by the method of the present invention as an electron donor for olefin polymerization catalysts.

detailed description

The following examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

Example 1

Preparation of dibutyl 2,3-diisopropylsuccinate

In a stainless steel reactor with a vacuum insulation interlayer, add 135ml of LDA synthesis reaction solution with a concentration of 1.3mol/L and 135ml of tetrahydrofuran (THF), and directly pass liquid nitrogen into the mixed solution under stirring. When the temperature is -80 At about ℃, drop the mixed solution of 0.15mol butyl isovalerate and 150ml THF into the reactor, adjust the amount of liquid nitrogen to maintain the reaction temperature, and continue to stir for 1h. At this temperature, a mixed solution of 0.27mol TiCl ₄ and 240ml CH ₂ Cl ₂ was added dropwise to the reaction liquid, and the reaction was stirred for another 2h. After the reaction was completed, 50 ml of water was added to quench the reaction. During the reaction, liquid nitrogen was vaporized as a protective gas for the reaction system.

After the reaction, the temperature of the reactor was slowly raised to room temperature, the reaction solution was extracted with 20ml×3 ethyl acetate, and the combined organic phase was neutralized and washed with 60ml of ₅ % NaHCO solution, and then washed with water until the organic phase Neutral. Dry with anhydrous magnesium sulfate, filter, and distill off the solvent under normal pressure; then distill the product under reduced pressure, collect the 2,3-diisopropyl dibutyl succinate fraction at 140°C/2mmHg, and obtain 15.28g of yellow viscous oil , Gas chromatograph analysis, the purity is 95.5%. The yield of dibutyl 2,3-diisopropylsuccinate was 83.6%.

Embodiment 2-7

In Examples 2-7, replace Example 1 with ethyl isovalerate, isobutyl isovalerate, isopropyl isovalerate, butyl butyrate, butyl isobutyrate and isobutyl propionate respectively Butyl isovalerate in, other steps are with embodiment 1. The results are shown in Table 1.

Table 1

Example 8

Toluene was used instead of tetrahydrofuran as the solvent, and other steps were the same as in Example 1. The yield of dibutyl 2,3-diisopropylsuccinate was 44.56%.

Example 9

The tetrahydrofuran solution mixed with butyl isovalerate and butyl butyrate was used to replace the tetrahydrofuran solution of isobutyl isovalerate, and the other steps were the same as in Example 1. Gas chromatographic analysis shows that the yield of 2,3-diethylsuccinic acid dibutyl ester is 5.80%, the yield of 2,3-diisopropyl succinic acid dibutyl ester is 32.18%, 2-ethyl-3-isopropyl The yield of dibutyl succinate is 31.28%.

Example 10

Referring to the conditions of document CN1313869A, a polymerization catalyst using dibutyl 2,3-diisopropylsuccinate as an internal electron donor was prepared, and the results of propylene polymerization are shown in Table 2.

The succinic acid ester prepared by the present invention is that the catalyst polymerization test value of the internal electron donor compares with the literature value

Succinate content/% Ti content/% Activity/gPP/g Bulk density of polypropylene g/ml Polypropylene isotacticity/% Literature value 17.4 4.60 62000 - 98.5 test value 13.75 3.28 62500 0.42 97.3

Claims (4)

1. The synthetic method of the 2,3-hydrocarbyl substituted succinic acid diester of preparation tool general formula I structure, comprises the process that carboxylate and strong base react in solvent to form enol metal salt and then oxidative coupling with oxidizing agent, its It is characterized in that: the liquid nitrogen is directly passed into the reactor, the reaction liquid is directly cooled, and the reaction temperature is -100°C to 25°C, and the liquid nitrogen is vaporized in the reaction process and used as an inert protective gas for the reaction system; the carboxyl The acid ester is at least one of the carboxylate esters with the general formula II structure; the strong base is pure lithium diisopropylamide, or the reaction mixture for preparing lithium diisopropylamide; the The solvent is an aprotic solvent with a low melting point, selected from one or more mixtures in ether, nitrile, halogenated hydrocarbon, aromatic hydrocarbon, paraffin, cycloalkane; the oxidant is titanium tetrachloride; the carboxylic acid Ester: strong base: oxidizing agent is 1:1～5:1～5; the concentration of the carboxylate is 0.05～10M, the concentration of strong base is 0.05～10M, and the concentration of oxidizing agent is 0.05～10M; in, R ₁ and R ₂ are each independently selected from H or a C ₁ -C ₂₀ hydrocarbon group, and the hydrocarbon group is a straight chain hydrocarbon group, a branched chain hydrocarbon group, a cyclohydrocarbyl group, a chain hydrocarbon group, a cyclohydrocarbyl group, a cyclohydrocarbyl chain hydrocarbon group, an aryl group, or a chain hydrocarbon group Aryl, aryl chain hydrocarbon group; R ₃ is selected from C ₁ -C ₂₀ hydrocarbon groups, and the hydrocarbon groups are straight-chain hydrocarbon groups, branched-chain hydrocarbon groups, cyclic hydrocarbon groups, chain hydrocarbon groups, cyclohydrocarbyl groups, cyclohydrocarbyl chain hydrocarbon groups, aryl groups, chain hydrocarbon aryl groups, and aryl chain hydrocarbon groups. 2. The method according to claim 1, characterized in that: the R ₁ and R ₂ are independently selected from H or C ₁ -C ₁₀ hydrocarbon groups, and the hydrocarbon groups are straight-chain hydrocarbon groups, branched-chain hydrocarbon groups, cyclic Hydrocarbyl, chain hydrocarbyl cyclohydrocarbyl, cyclohydrocarbyl chain hydrocarbyl, aryl, chain hydrocarbyl aryl, aryl chain hydrocarbyl; R ₃ is selected from C ₁ -C ₁₀ hydrocarbon groups, and the hydrocarbon groups are linear hydrocarbon groups, branched chain hydrocarbon groups, cyclic hydrocarbon groups, chain hydrocarbon groups, cyclohydrocarbyl groups, cyclohydrocarbyl chain hydrocarbon groups, aryl groups, chain hydrocarbon aryl groups, and aryl chain hydrocarbon groups. 3. The method according to claim 1, characterized in that: the aprotic solvent is selected from ether, isopropyl ether, 1,2-dimethoxyethane, tetrahydrofuran, acetonitrile, dichloromethane, dichloroethane One or more mixtures of alkanes, toluene, ethylbenzene, pentane, hexane, heptane, cyclopentane, methylcyclopentane, methylcyclohexane, dimethylcyclohexane. 4. The method according to any one of claims 1 to 3, characterized in that: the liquid nitrogen is passed into the reactor to directly cool the reaction liquid, so that the reaction temperature is -90°C to -20°C, and the reaction process After the liquid nitrogen is vaporized, it is used as an inert protective gas for the reaction system.