Dodecene synthesis method and product

Abstract

The invention discloses a dodecene synthesis method and a product, and the dodecene synthesis method comprises the following steps: S1, mixing isobutene, a solvent and C8 olefin according to a certain ratio, feeding into a tubular reactor, and controlling the reaction temperature to be 40-150 DEG C and the reaction pressure to be 1-5 MPa under the action of a catalyst; s2, distilling the reaction liquid, and recovering the solvent and C8 olefin; and S3, carrying out reduced pressure distillation to obtain the product dodecene, and returning the recovered solvent and C8 olefin to the reaction to participate in the reaction. The synthetic route is simple to operate, the reaction temperature is better to control, the reaction is safer, the raw material utilization rate is higher, the product quality is better, and the quality guarantee of downstream products is more facilitated.

Description

Technical Field

[0001] The invention belongs to the field of organic polymerization, and more specifically, relates to a synthesis method and product of dodecene. Background Art

[0002] With the promotion of ethanol gasoline, methyl tert-butyl ether (MTBE) will gradually withdraw from the market, and a large number of isobutylene resources need to consider future solutions. The oligomerization products obtained by oligomerization reaction with isobutylene as raw material mainly include dimerization products (DIB), trimerization products (TIB), and tetramerization products (hexadecene). They are all high value-added derivatives of isobutylene downstream, and are important intermediates for the preparation of surfactants, detergents and plasticizers. They can also be used in flavors, fragrances, medicines and dye industries. At the same time, using isobutylene as raw material to produce chemical raw material intermediates can effectively alleviate the unfavorable market situation of isobutylene oversupply.

[0003] There are generally two ways to use C8 olefins: one is to produce high-octane alkylated gasoline; the other is to produce plasticizers, mainly octylphenol and isononanol. Dodecene and hexadecene can be hydrogenated to produce isododecane and isohexadecane, respectively. Isododecane and isohexadecane have a large market demand and are mainly used in the fields of synthetic detergent surfactants, polyolefin production and processing, fuel additives, lubricant base oils, and cosmetics.

[0004] At present, the main problem with isobutylene polymerization is that the reaction releases a large amount of heat and is difficult to control the temperature, which has a great impact on the product quality and the activity and life of the catalyst, and can easily cause the catalyst activity to decrease. In particular, when isobutylene is polymerized to prepare dodecene, the conversion rate and selectivity are low when the temperature is too low; when the temperature is too high, the amount of hexadecene and even olefins with higher carbon numbers increases, and excessively high polymers are easily precipitated, blocking the pipeline, causing the distillation system to be disordered, and the product quality is not ideal.

[0005] Patent publication CN1137420A provides a catalyst and process for preparing C8 and C12 olefins by polymerization of butene. The reaction conditions of the butene polymerization process are temperature 80-220°C, pressure 2.0-5.0Mpa, and space velocity of the raw material liquid 0.5-5h -1 The catalyst is: Al 2 O 3 and X-amorphous aluminum silicate as a composite carrier, loaded with or without NiO. The process mainly produces C8 olefins, with dodecene as a by-product.

[0006] Patent document with publication number CN106938968A discloses a method and device for preparing diisobutylene, triisobutylene and tetraisobutylene by polymerization of isobutylene, with a reaction temperature of 120-180°C, a reaction pressure of 1-5MPa, a polymerization device of three-stage polymerization reaction device, equipped with a feed pump and a three-stage circulation device, and a catalyst prepared by mixing molecular sieve and other catalysts. The specific reaction results are not mentioned in the scheme.

[0007] The patent with publication number CN113636903A reports a method for preparing triisobutylene by polymerization of isobutylene, using a two-stage cascade reactor, the feed temperature of the raw material isobutylene is 60-90°C and 30-50°C, the pressure is 2-4MPa and 1-2MPa, and the space velocity is 4-8h -1 , 0.3-2h -1 The secondary reaction inlet material is a mixture of three materials (the primary reactor outlet material, the separation tower top circulating material and the added isobutylene) to prepare 40-60wt% of isobutylene, 30-50wt% of diisobutylene and 3-10wt% of triisobutylene. The final reaction product contains only isobutylene, diisobutylene and triisobutylene, and the content of triisobutylene is greater than 95%.

[0008] Patent publication number CN116514626A reports a method for preparing trimerization products by highly selective polymerization of isobutylene. The method uses a Cu-loaded molecular sieve as a catalyst, and the mixed C4 raw gas reacts at a temperature of 50-80°C and a pressure of 0.5-3MPa. After the reaction, the selectivity of dodecene is greater than 70%, and the selectivity of hexadecene is about 14%. Summary of the invention

[0009] The object of the present invention is to provide a method for synthesizing dodecene, which realizes the synthesis of dodecene, makes the reaction temperature easier to control, and reduces catalyst deactivation and loss; at the same time, effectively improves the conversion rate of dodecene and reduces the content of hexadecene, the synthesis route is simple, and the operation is safer; in addition, another invention object of the present invention based on the method for synthesizing dodecene is to obtain dodecene with higher product quality.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A method for synthesizing dodecene of the present invention comprises the following steps:

[0012] S1. Add isobutylene, solvent and C8 olefin into a tubular reactor, and control the reaction temperature to 40-150°C and the reaction pressure to 1-5MPa under the action of a strong acid resin catalyst;

[0013] S2. The reaction solution is distilled to recover the solvent and C8 olefins;

[0014] S3. The product dodecene is obtained by vacuum distillation, and the recovered solvent and carbon octaolefin are returned to the reaction to participate in the reaction;

[0015] The solvent in step S1 is selected from one or more alkanes having 5 to 10 carbon atoms.

[0016] The synthetic chemical formula for preparing dodecene according to the present invention is as follows:

[0017]

[0018] As a further improvement of the present invention, the solvent of step S1 is an alkane with 5 or 6 carbon atoms; more preferably, cyclopentane or n-hexane is used as the solvent.

[0019] As a further improvement of the present invention, the molar mass ratio of isobutylene, solvent and C8 olefin in the above step S1 is 50:1-50:0-49; further preferably 50:1-50:0-45; the solvent is in excess relative to the C8 olefin to fully dissolve the raw materials and improve the purity of the final dodecene product.

[0020] As a further improvement of the present invention, the reaction temperature in step S1 is further preferably 50-120°C.

[0021] As a further improvement of the present invention, the reaction pressure in step S1 is further preferably 2.5-3.5 MPa.

[0022] As a further improvement of the present invention, the above step S1 adds the solvent, C8 olefin and isobutylene into the raw material tank in sequence for premixing, which can effectively reduce the compression risk of isobutylene gas phase compressed feed and make storage safer; it can also make it easier to control the reaction temperature and will not produce many side reactions in the tubular reactor due to excessive local temperature; after premixing, it is pumped to the reactor for reaction.

[0023] As a further improvement of the present invention, the amount of catalyst in step S1 is set according to the size of the reactor, and the liquid space velocity is controlled to be 0.5-6h -1 ; More preferably 3.5-4.5h -1 .

[0024] As a further improvement of the present invention, the reaction in step S1 is carried out under intermittent protection of an inert gas; the inert gas comprises any one of nitrogen, helium or argon or a mixture of at least two of them; and is used to increase the pressure when the reaction pressure is reduced.

[0025] As a further improvement of the present invention, the solvent and C8 olefin in the above step S2 are condensed and recovered after being distilled at 80-180° C. under normal pressure.

[0026] As a further improvement of the present invention, in the above step S3, the residual liquid from the distillation of step S2 is subjected to reduced pressure distillation at 85-95° C. to obtain the product dodecene.

[0027] Dodecene is prepared by any of the above-mentioned preparation methods.

[0028] As a further improvement of the present invention, the main component of the dodecene is a mixture of various isomers such as 2,4,4,6,6-pentamethylheptene-2 ​​and 2,4,4,6,6-pentamethylheptene-1.

[0029] As a further improvement of the present invention, the above-mentioned dodecene mixture is a light yellow to colorless oily liquid with a boiling point of 175-185°C and a density of about 0.7-0.8 g / cm 3 .

[0030] As a further improvement of the present invention, the content of the main component of dodecene is not less than 99.95%.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) By using isobutylene to directly react with C8 olefins to obtain dodecene, the raw material utilization rate is high and the reaction process is simpler. At the same time, isobutylene itself undergoes polymerization to generate C8 olefins, so that the raw material C8 olefins are continuously replenished, effectively reducing the production cost; at the same time, the solvent and the reactants are premixed evenly, so that the reaction temperature is easier to control, the catalyst activity and selectivity are higher, and the conversion rate of dodecene is improved;

[0033] (2) By using a mixture of isobutylene, solvent and C8 olefins, the compression risk of isobutylene gas phase compressed feed is reduced, storage is safer, and the material mixing is more uniform and the reaction is more complete;

[0034] (3) By using a strong acid resin catalyst, it is not only simple and easy to obtain, but also can effectively reduce the damage and deactivation of the catalyst under this operating condition, which belongs to the category of green and safe chemistry;

[0035] (4) The by-products generated after the reaction can be distilled and purified and then reused in the reaction system, thus achieving comprehensive recycling and meeting the requirements of clean chemical production. DETAILED DESCRIPTION

[0036] The synthetic chemical formula for preparing dodecene according to the present invention is as follows:

[0037]

[0038] Example 1: n-hexane (24 mol, 2068.4 g), C8 olefin (16 mol, 1760 g) and isobutylene (40 mol, 2248 g) were added to an 8 L raw material tank in sequence and premixed. -1 The reaction mixture was pumped into a tubular reactor filled with a strong acid resin catalyst at a liquid space velocity of 1.5 %; nitrogen was intermittently introduced at a constant volume for protection, and the reaction was continued at a temperature of 70°C and a pressure of 3 MPa. After the reaction was stabilized, a light yellow to colorless oily liquid was obtained. 4000 mL of the reaction solution was weighed and added to a distillation tower for distillation at room temperature of 130°C, and mixed C8 olefins were obtained by condensation and recovery; the distillation residue was subjected to reduced pressure distillation at 90°C, and the product dodecene was obtained by distillation; after liquid phase detection and analysis, the proportion of isobutylene raw materials was 0.96%, the proportion of C8 olefins was 23.5%, the proportion of dodecene was 69.2%, and the proportion of hexadecene was 4.2%. Therefore, the conversion rate of isobutylene was 99.04%, the selectivity of dodecene was 76.5%, and the yield of dodecene was 75.8%. The obtained dodecene was weighed and analyzed by gas chromatography, and the purity of dodecene was 99.96%.

[0039] Comparative Example 1: n-hexane (24 mol, 2068.4 g), C8 olefin (16 mol, 1760 g) and isobutylene (40 mol, 2248 g) were added to an 8 L raw material tank in sequence and pre-mixed. -1 The reaction mixture was pumped into a tubular reactor filled with a composite oxide catalyst at a liquid space velocity of 100°C; nitrogen was intermittently introduced at a constant volume for protection, and the reaction was continued at a temperature of 100°C and a pressure of 3MPa, and a light yellow to colorless oily liquid was obtained after the reaction was stabilized. 4000mL of the reaction solution was weighed and added to a distillation tower for distillation at room temperature of 130°C, and mixed C8 olefins were obtained by condensation and recovery; the distillation residue was subjected to reduced pressure distillation at 90°C, and the product dodecene was obtained by distillation; after liquid phase detection and analysis, the proportion of isobutylene raw materials was 2.5%, the proportion of C8 olefins was 23.9%, the proportion of dodecene was 67.4%, and the proportion of hexadecene was 4.1%, so the isobutylene conversion rate was 97.5%, the selectivity of dodecene was 75.6%, and the yield of dodecene was 73.7%. The purity of dodecene was 99.95% after gravimetric analysis by gas chromatography.

[0040] By comparing Example 1 with Comparative Example 1, the preferred strong acid resin catalyst of the present invention is compared with the composite oxide catalyst, and the product dodecene selectivity and yield are higher, and the isobutylene raw material conversion rate is also higher. Therefore, the preferred strong acid resin catalyst of the present invention can improve the catalytic effect.

[0041] Comparative Example 2: C8 olefin (16 mol, 1760 g) and isobutylene (40 mol, 2248 g) were added to an 8 L raw material tank in sequence and premixed. -1The reaction mixture was pumped into a tubular reactor filled with a strong acid resin catalyst at a liquid space velocity of 100°C; nitrogen was intermittently introduced at a constant volume for protection, and the reaction was continued at a temperature of 100°C and a pressure of 3MPa, and a light yellow to colorless oily liquid was obtained after the reaction was stabilized. 4000mL of the reaction solution was weighed and added to a distillation tower for distillation at room temperature of 130°C, and mixed C8 olefins were obtained by condensation and recovery; the distillation residue was subjected to reduced pressure distillation at 90°C, and the product dodecene was obtained by distillation; after liquid phase detection and analysis, the proportion of isobutylene raw materials was 1.5%, the proportion of C8 olefins was 23.7%, the proportion of dodecene was 69.4%, and the proportion of hexadecene was 4.7%, so the conversion rate of isobutylene was 98.5%, the selectivity of dodecene was 75.9%, and the yield of dodecene was 74.7%. The obtained dodecene was weighed and analyzed by gas chromatography, and the purity of dodecene was 99.95%.

[0042] By comparing Example 1 with Comparative Example 2, the n-hexane selected as the reaction solvent in the present invention is compared with the direct reaction without selecting a solvent. The addition of a solvent can avoid local overheating during the reaction, thereby reducing the by-product hexadecene in the reaction. Therefore, the n-hexane selected as the reaction solvent in the present invention can improve the selectivity of dodecene and reduce the production of the by-product hexadecene.

[0043] Example 2: n-hexane (15 mol, 1292.5 g), C8 olefin (9 mol, 990 g) and isobutylene (63 mol, 3540.6 g) were added to a 9 L raw material tank in sequence and premixed. -1 The reaction mixture was pumped into a tubular reactor filled with a strong acid resin catalyst at a liquid space velocity of 100°C; nitrogen was intermittently introduced at a constant volume for protection, and the reaction was continued at a temperature of 100°C and a pressure of 3MPa, and a light yellow to colorless oily liquid was obtained after the reaction was stabilized. 4000mL of the reaction solution was weighed and added to a distillation tower for distillation at room temperature of 130°C, and mixed C8 olefins were obtained by condensation and recovery; the distillation residue was subjected to reduced pressure distillation at 90°C to distill out the product dodecene; after liquid phase detection and analysis, the proportion of isobutylene raw material was 1%, the proportion of C8 olefins was 24.2%, the proportion of dodecene was 68.9%, and the proportion of hexadecene was 4.1%, so the conversion rate of isobutylene was 99%, the selectivity of dodecene was 76.1%, and the yield of dodecene was 75.3%. The obtained dodecene was weighed and analyzed by gas chromatography, and the purity of dodecene was 99.96%.

[0044] Example 3: n-hexane (24 mol, 2068.4 g), C8 olefin (16 mol, 1760 g) and isobutylene (40 mol, 2248 g) were added to an 8 L raw material tank in sequence and premixed. -1The reaction mixture was pumped into a tubular reactor filled with a strong acid resin catalyst at a liquid space velocity of 1.5 %; nitrogen was intermittently introduced at a constant volume for protection, and the reaction was continued at a temperature of 90°C and a pressure of 3 MPa. After the reaction was stabilized, a light yellow to colorless oily liquid was obtained. 4000 mL of the reaction solution was weighed and added to a distillation tower for distillation at room temperature of 130°C, and mixed C8 olefins were obtained by condensation and recovery; the distillation residue was subjected to reduced pressure distillation at 90°C, and the product dodecene was obtained by distillation; after liquid phase detection and analysis, the proportion of isobutylene raw materials was 0.93%, the proportion of C8 olefins was 23.2%, the proportion of dodecene was 69.6%, and the proportion of hexadecene was 4.3%. Therefore, the conversion rate of isobutylene was 99.07%, the selectivity of dodecene was 76.7%, and the yield of dodecene was 76%. The obtained dodecene was weighed and analyzed by gas chromatography, and the purity of dodecene was 99.96%.

[0045] Example 4: Cyclopentane (24 mol, 1683.1 g), C8 olefin (16 mol, 1760 g) and isobutylene (40 mol, 2248 g) were added to an 8 L raw material tank in sequence and premixed. -1 The reaction mixture was pumped into a tubular reactor filled with a strong acid resin catalyst at a liquid space velocity of 1000 μg / min; nitrogen was intermittently introduced at a constant volume for protection, and the reaction was continued at a temperature of 110°C and a pressure of 3 MPa, and a light yellow to colorless oily liquid was obtained after the reaction was stabilized. 4000 mL of the reaction solution was weighed and added to a distillation tower for distillation at room temperature of 130°C, and mixed C8 olefins were obtained by condensation and recovery; the distillation residue was subjected to reduced pressure distillation at 90°C to distill out the product dodecene; after liquid phase detection and analysis, the isobutylene raw material accounted for 0.92%, the C8 olefin accounted for 22.9%, the dodecene accounted for 69.7%, and the hexadecene accounted for 4.4%, so the isobutylene conversion rate was 99.08%, the dodecene selectivity was 76.6%, and the dodecene yield was 75.9%. The obtained dodecene was weighed and analyzed by gas chromatography, and the purity of dodecene was 99.7%.

[0046]

[0047] The results in the above table show that in the method for synthesizing dodecene of the present invention, isobutylene exhibits a high conversion rate and selectivity in terms of selective polymerization. It can be seen from the results in the table that as the proportion of C8 olefins increases within a certain range, the isobutylene conversion rate and the selectivity of dodecene can be effectively improved; as the temperature increases within a certain range, the catalyst exhibits better activity, and the selectivity of dodecene increases accordingly. At the same time, the yield of dodecene can be maintained at a high level within a certain range of temperature changes, so the reaction temperature is also easier to control; the purity of dodecene synthesized by the method for synthesizing dodecene of the present invention can reach more than 99.95%, which improves the product quality compared to the dodecene obtained by the prior art, and provides raw material guarantee for downstream products.

[0048] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for synthesizing dodecene, Features: The following steps are involved: S1. Add isobutylene, solvent and C8 olefin into a tubular reactor, and control the reaction temperature to 40-150°C and the reaction pressure to 1-5MPa under the action of a strong acid resin catalyst; S2. The reaction solution is distilled to recover the solvent and C8 olefins; S3. The dodecene product is obtained by vacuum distillation, and the recovered solvent and the eight carbon olefins are returned to the reaction to participate in the reaction; The solvent in step S1 is selected from one or more alkanes having 5 to 10 carbon atoms.

2. A method for synthesizing dodecene according to claim 1, Features: In step S1, the solvent is an alkane with 5 or 6 carbon atoms.

3. A method for synthesizing dodecene according to claim 1, Features: In the step S1, the molar mass ratio of isobutylene, solvent and C8 olefin is 50:1-50:0-49.

4. A method for synthesizing dodecene according to claim 1, Features: In step S1, the solvent, C8 olefin and isobutylene are sequentially added into a raw material tank for premixing, and then pumped to a reactor for reaction.

5. A method for synthesizing dodecene according to claim 1, Features: The amount of catalyst in step S1 is set according to the reactor size, and the liquid space velocity is controlled to be 0.5-6h -1 .

6. A method for synthesizing dodecene according to claim 1, Features: In step S1, an inert gas is intermittently introduced into the tubular reactor; the inert gas includes any one of nitrogen, helium or argon, or a mixture of at least two of them.

7. Dodecene, It is characterized in that The invention is prepared by the preparation method according to any one of claims 1 to 6.

8. Dodecene according to claim 7, It is characterized in that The main component of dodecene is a mixture of multiple isomers such as 2,4,4,6,6-pentamethylheptene-2 ​​and 2,4,4,6,6-pentamethylheptene-1.

9. Dodecene according to claim 7, It is characterized in that The dodecene mixture has a boiling point of 175-185°C and a density of about 0.7-0.8 g / cm 3 .

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