Method for preparing higher carbon esters of acetic acid from Fischer-Tropsch olefins and its product

Abstract

The present invention provides a method for preparing higher-carbon acetic esters from Fischer-Tropsch olefins and its products. The method includes: Step S1, subjecting the Fischer-Tropsch synthesis product to rectification cutting to obtain Cn single-carbon components, where n is any one or more of integers from 5 to 13; Step S2, under the action of a catalyst, introducing the Cn single-carbon components into a reactor respectively to carry out Markovnikov addition reaction with acetic acid, and obtaining the corresponding acetic esters through rectification. Using the Fischer-Tropsch synthesis product as a raw material to prepare carboxylic esters with different carbon chain lengths, since the Fischer-Tropsch synthesis product contains a large amount of odd-carbon α-olefins, carboxylic esters with different carbon chain lengths can be prepared, enriching the types of carboxylic ester products. Moreover, using the Fischer-Tropsch synthesis product as a raw material, the cost is relatively low, and the alkane components in the raw material dilute the reaction system, making the reaction easier to control, and solving the technical problem of high temperature control requirements for the system due to poor thermal stability of the catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of carboxylic ester synthesis, and in particular, to a method for preparing higher carbon acetic esters from Fischer-Tropsch olefins and its products. Background Art

[0002] Carboxylic ester compounds are a class of widely used chemical products, which can be used as solvents, plasticizers, surfactants, polymerization monomers, etc. Since higher carbon carboxylic esters have the aroma of rose, hyacinth, narcissus, jonquil, lilac, lily of the valley, jasmine, sweet pea flower, linden flower, primrose or honey fragrance and a sweet fruity taste, they are often used as fragrances in soap fragrances, food flavors and coatings.

[0003] Currently, the process for producing carboxylic esters mainly uses the acid-alcohol esterification method, and the acid-alcohol esterification method mostly uses concentrated sulfuric acid as a catalyst, resulting in serious equipment corrosion. And it is necessary to remove the sulfuric acid catalyst through neutralization and water washing steps, leading to a large amount of reaction waste liquid. For some higher carbon alcohols with large steric hindrance, more reactive acid anhydrides or acyl chlorides are required for the reaction. The acid-alcohol esterification method has problems such as equipment corrosion, many side reactions and difficult waste liquid treatment.

[0004] Jin Lie et al. (Synthesis of n-hexyl acetate catalyzed by nano-H3PW 12 O 40 / SiO2 composite heteropolyacid [J]. Applied Chemical Industry, 2011, 40(12): 2179-2181.) reported the synthesis of higher carbon carboxylic esters using glacial acetic acid and n-hexanol as raw materials. However, using heteropolyacid catalysts is prone to coking, accelerating the inactivation of the catalyst.

[0005] The Chinese patent application with the publication number CN101838198A uses ionic liquid as a catalyst and at the same time as an extractant. After catalyzing the esterification of olefins and carboxylic acids, the produced carboxylic esters are separated from the unreacted carboxylic acids. However, the recovery cost of ionic liquid as a catalyst is high.

[0006] The raw materials selected for carboxylic ester synthesis are higher carbon olefins and higher carbon alcohols. The carbon atoms of the α-olefins produced by the ethylene oligomerization method are all even numbers, and the types of corresponding carboxylic ester products are few, and the cost is very high at the same time. As a raw material, for some higher carbon alcohols with large steric hindrance, more reactive acid anhydrides or acyl chlorides are required for the reaction.

[0007] The middle product of Fischer-Tropsch synthesis, the oil-washed naphtha in the coal-to-oil project, has the characteristics of high α-olefin content and no sulfur, nitrogen, aromatics, etc. α-olefins are important raw materials for producing products such as olefin copolymers, plasticized alcohols, surfactants, oilfield chemicals, and lubricants, and are involved in multiple industries such as petrochemicals, light industry, metallurgy, textiles, pesticides, and pharmaceuticals. The direct synthesis of carboxylic acid esters from olefins and carboxylic acids has a raw material cost far lower than that of the esterification of higher carbon alcohols and carboxylic acids, can significantly reduce production costs. At the same time, the addition esterification is an atom-economic reaction, which can effectively reduce the emission of three wastes and conforms to the concept of low-carbon emissions. Summary of the Invention

[0008] The main object of the present invention is to provide a method for preparing higher-carbon acetic esters from Fischer-Tropsch olefins and its products to solve the problems of difficult synthesis and high cost of higher-carbon acetic esters in the prior art.

[0009] To achieve the above object, according to one aspect of the present invention, a method for preparing higher-carbon acetic esters from Fischer-Tropsch olefins is provided. The method includes: Step S1, subjecting the Fischer-Tropsch synthesis product to rectification cutting to obtain Cn single-carbon components, where n is any one or more of integers from 5 to 13; Step S2, under the action of a catalyst, introducing the Cn single-carbon components into a reactor respectively to perform Markov addition reaction with acetic acid, and obtaining the corresponding acetic esters through rectification.

[0010] Further, the Fischer-Tropsch synthesis product is oil-washed naphtha;

[0011] Preferably, Step S1 includes first removing the oxygen-containing compounds in the Fischer-Tropsch synthesis product to obtain deoxygenated refined Fischer-Tropsch synthesis oil, and then performing rectification cutting on the deoxygenated refined Fischer-Tropsch synthesis oil;

[0012] Preferably, the oxygen-containing compounds in the Fischer-Tropsch synthesis product are removed by extraction, and the extractant is any one or more of 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. Preferably, the mass ratio of the extractant to the Fischer-Tropsch synthesis product is 3-4:1.

[0013] Further, the content of single-carbon olefins in the Cn single-carbon components is 50%-70%, the content of single-carbon alkanes is 30%-50%, and the content of oxygen-containing compounds is 3%-4.5%; preferably, the molar ratio of acetic acid to single-carbon olefins is 1.5-4:1.

[0014] Further, the catalyst is a strongly acidic cation exchange resin. Preferably, the strongly acidic cation exchange resin is selected from any one or more of D002-CC, D072, and NKC-9.

[0015] Further, the reactor is a fixed-bed reactor. Preferably, ceramic balls are installed at the bottom of the fixed-bed reactor, and the catalyst is arranged on the ceramic balls. Preferably, ceramic balls are also installed at the position between the upper wall of the reactor and above the catalyst.

[0016] Further, the pressure of the Markov addition reaction is 1 - 3 MPa. Preferably, the temperature of the Markov addition reaction is 120 - 160 °C. Preferably, the time of the Markov addition reaction is 1 - 2 h. Preferably, the feed mass space velocity of the Cn single-carbon component is 1 - 4 h -1 。

[0017] Further, the Markov addition reaction is carried out in an inert gas atmosphere.

[0018] Further, in step S2, the alkane by-product is separated by distillation. Preferably, the purity of the alkane by-product is ≥90%.

[0019] Further, in step S2, acetic acid is separated by distillation and fed into the reactor as a reaction raw material.

[0020] According to another aspect of the present invention, a higher-carbon acetate is provided, which is prepared by the method for preparing a higher-carbon acetate from Fischer-Tropsch olefins of any of the above.

[0021] Applying the technical solution of the present invention, using the Fischer-Tropsch synthesis product as a raw material to prepare carboxylic acid esters with different carbon chain lengths. Since the Fischer-Tropsch synthesis product contains a large amount of odd-carbon α-olefins, carboxylic acid esters with different carbon chain lengths can be prepared, enriching the variety of carboxylic acid ester products. Moreover, using the Fischer-Tropsch synthesis product as a raw material, the cost is relatively low. The alkane component in the raw material dilutes the reaction system, making the reaction easier to control, and solving the technical problem of high temperature control requirements for the system due to poor thermal stability of the catalyst. Further, since the alkane component that is difficult to separate in the Fischer-Tropsch synthesis product does not participate in the reaction, it is easy to effectively separate from the carboxylic acid ester product after addition esterification, obtaining a single alkane product with higher value, and solving the technical problem of difficult separation of alkane and alkene. Specific Embodiments

[0022] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0023] As analyzed in the background art of the present application, in the prior art, there are problems of high difficulty and high cost in synthesizing higher-carbon number acetate esters. To solve this problem, the present application provides a method for preparing a higher-carbon acetate from Fischer-Tropsch olefins and its product.

[0024] According to a typical embodiment of the present application, a method for preparing higher carbon esters of acetic acid from Fischer-Tropsch olefins is provided. The method includes: Step S1, subjecting the Fischer-Tropsch synthesis product to rectification cutting to obtain Cn single-carbon components, where n is any one or more of integers from 5 to 9; Step S2, under the action of a catalyst, introducing the Cn single-carbon components into a reactor respectively to carry out Markov addition reaction with acetic acid, and rectifying to obtain the corresponding acetic acid esters.

[0025] The present application uses the Fischer-Tropsch synthesis product as a raw material to prepare carboxylic acid esters with different carbon chain lengths. Since the Fischer-Tropsch synthesis product contains a large amount of odd-carbon α-olefins, carboxylic acid esters with different carbon chain lengths can be prepared, enriching the variety of carboxylic acid ester products. Moreover, using the Fischer-Tropsch synthesis product as a raw material, the cost is relatively low, and the alkane components in the raw material dilute the reaction system, making the reaction easier to control, and solving the technical problem of high temperature control requirements for the system due to poor thermal stability of the catalyst. Further, since the alkane components that are difficult to separate in the Fischer-Tropsch synthesis product do not participate in the reaction, they are easily separated from the carboxylic acid ester product after addition esterification, obtaining a single alkane product with higher value, and solving the technical problem of difficult separation of alkanes and alkenes.

[0026] The above Fischer-Tropsch synthesis product can be selected from the prior art without special requirements. In some embodiments of the present application, the above Fischer-Tropsch synthesis product is washed naphtha. The carbon number distribution of washed naphtha is mainly concentrated in 4-12, which is a specific preferred raw material for addition esterification. After being cut into single carbon, it can realize the production of acetic acid ester products in the whole distillation section.

[0027] Since there is generally a certain content of oxygen-containing compounds in the Fischer-Tropsch synthesis product, in order to further improve the purity of the target product, it is preferably to separate the oxygen-containing compounds in the olefin raw material participating in the esterification reaction first. The treatment of separating oxygen-containing compounds can be carried out before or after the rectification cutting of single carbon. In some embodiments of the present application, in order to improve the treatment efficiency, the oxygen-containing compounds in the Fischer-Tropsch synthesis product are first removed to obtain deoxygenated refined Fischer-Tropsch synthesis oil, and then the deoxygenated refined Fischer-Tropsch synthesis oil is subjected to rectification cutting.

[0028] The method for removing oxygen-containing compounds from the Fischer-Tropsch synthesis product can be selected from the prior art. In some embodiments of the present application, the oxygen-containing compounds in the Fischer-Tropsch synthesis product are removed by extraction. The extractant is any one or more of 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. Not only is the oxide removal efficiency relatively high and the oil loss rate is relatively low, but also the residual extractant is easily separated by subsequent rectification cutting. Preferably, the mass ratio of the extractant to the Fischer-Tropsch synthesis product is 3-4:1, which can further improve the removal efficiency of oxygen-containing compounds. In some embodiments of the present application, the oxide content of the oil after extraction is 800-1000 ppm, and the oil loss rate is 3-5%.

[0029] Those skilled in the art can determine the implementation methods and devices for the above rectification cutting according to the prior art, and will not be described in detail here. In some embodiments of the present application, the content of monocarbon olefins in the Cn monocarbon component is 50%-70%, the content of monocarbon alkanes is 30%-50%, and the content of oxygenates is 3%-4.5%. The subsequent Markov addition reaction has better effects, good product selectivity, and the reaction is easier to control.

[0030] In some typical embodiments of the present application, the above catalyst is a strongly acidic cation exchange resin. Since the alkane component in the raw material dilutes the reaction system, the reaction of the present application is easier to control, solving the technical problem of high temperature control requirements for the system due to the poor thermal stability of the strongly acidic cation exchange resin. Therefore, it is not only convenient for process control, but also can significantly improve the yield of the target product. At the same time, using a strongly acidic cation exchange resin as the catalyst solves the problems of equipment corrosion, many side reactions, and difficult treatment of a large amount of waste liquid when using sulfuric acid as the catalyst.

[0031] The above strongly acidic cation exchange resin can be selected from the prior art. In some preferred embodiments of the present application, when the above strongly acidic cation exchange resin is selected from any one or more of D002-CC, D072, and NKC-9, the yield of the target product is significantly improved. Preferably, the strongly acidic cation exchange resin is soaked in acetic acid for 24-48 h before use, which is beneficial to further improving the catalytic effect.

[0032] The method for preparing higher carbon esters of acetic acid from Fischer-Tropsch olefins in the present application has no special requirements for the reactor. In some embodiments of the present application, when the catalyst is a strongly acidic cation exchange resin, a fixed-bed reactor is used, which is beneficial to further improving the reaction efficiency. In some preferred embodiments of the present application, ceramic balls are installed at the bottom of the fixed-bed reactor, and the catalyst is arranged on the ceramic balls. Preferably, ceramic balls are also installed at the position between the catalyst and the upper wall of the reactor, which is convenient for the reaction raw materials to fully contact with the catalyst and improves the catalytic efficiency.

[0033] In some typical embodiments of the present application, the pressure of the above Markov addition reaction is 1-3 MPa. Too high or too low pressure is not conducive to the progress of the reaction. In some preferred embodiments of the present application, the temperature of the Markov addition reaction is 120-160 °C, the raw materials have a high conversion rate, and the selectivity of the target product is good. Preferably, the time of the Markov addition reaction is 1-2 h, and the feed mass space velocity of the Cn monocarbon component is 1-4 h -1 。

[0034] The molar ratio of the two reaction raw materials, acetic acid and monocarbon olefin, in the above-mentioned Markov addition reaction can be determined according to the stoichiometric ratio of the reaction. In some preferred embodiments of the present application, in order to further improve the conversion rate of the olefin, the molar ratio of acetic acid to monocarbon olefin is 1.5 - 4:1.

[0035] In order to further improve the selectivity of the reaction, the above-mentioned Markov addition reaction is carried out in an inert gas atmosphere.

[0036] In some embodiments of the present application, the conversion rate of the olefin in step S2 is ≥90%, or ≥92%, or ≥94%, or ≥96%, or ≥97%, and the selectivity of the product acetate is ≥90%, or ≥92%, or ≥94%, or ≥96%, or ≥97%, or ≥98%, or ≥98.5%, or ≥99%.

[0037] The main components in the material after the reaction are the corresponding acetate products, alkanes, and unreacted acetic acid. Through rectification, the above components can be easily separated. In some typical embodiments of the present application, the alkane by-product is separated by rectification in step S2, and preferably the purity of the alkane is ≥90%.

[0038] In some embodiments of the present application, acetic acid is separated by rectification, and the obtained acetic acid is recycled as a reaction raw material and fed into the reactor again for recycling.

[0039] According to another typical embodiment of the present application, a higher-carbon acetate is provided, which is prepared by the method for preparing a higher-carbon acetate from Fischer-Tropsch olefin of any one of the above.

[0040] The present application uses Fischer-Tropsch synthesis products as raw materials to prepare carboxylic acid esters with different carbon chain lengths. Since the Fischer-Tropsch synthesis products contain a large amount of odd-carbon α-olefins, carboxylic acid esters with different carbon chain lengths can be prepared, enriching the variety of carboxylic acid ester products. Moreover, using Fischer-Tropsch synthesis products as raw materials has a lower cost. The alkane components in the raw materials dilute the reaction system, making the reaction easier to control, and solving the technical problem of high temperature control requirements for the system due to poor thermal stability of the catalyst. Further, since the alkane components that are difficult to separate in the Fischer-Tropsch synthesis products do not participate in the reaction, they are easily separated from the carboxylic acid ester products after addition esterification, obtaining higher-value single-alkane products, and solving the technical problem of difficult separation of alkanes and alkenes. The higher-carbon acetate of the present application has a relatively simple process, greatly reducing the production cost.

[0041] The beneficial effects that can be achieved by the present application will be further described below in conjunction with examples and comparative examples.

[0042] Example 1

[0043] Preparation of C5, C6, C7, C8, C9 monocarbon components

[0044] The Fischer-Tropsch synthetic oil-washed naphtha, whose composition is shown in Table 1, has a hydrocarbon content of 96.83% and an oxygenate content of 3.1%, with the rest being impurities. First, 1,2-propanediol is used as an extractant, and the mass ratio of the extractant to the oil is 3:1. Under normal temperature and pressure, the oxygenates in the oil-washed naphtha are removed. After the oil-washed naphtha is deoxygenated, the oxide content is 900 ppm. Then, under atmospheric pressure, the oil-washed naphtha is rectified to cut it into single-carbon components of C5, C6, C7, C8, and C9, and the content of the single-carbon components is 99%.

[0045] Table 1

[0046]

[0047] Example 2

[0048] Preparation of 1-methylbutyl acetate

[0049] 20 g of a strongly acidic cation exchange resin D002-CC catalyst is loaded into a φ32×6×700 mm fixed-bed reactor 1, and the upper and lower ends of the catalyst loading section are filled with porcelain balls. The fixed-bed reactor is purged with nitrogen to a nitrogen environment, the reactor pressure is controlled at 1 MPa, and the temperature is controlled at 120 °C. Glacial acetic acid raw materials with a purity of 98% are fed into the fixed-bed reactor at a feeding rate of 30 g / h. The raw materials are the C5 single-carbon components separated in Example 1 and are fed into the fixed-bed reactor at a feeding rate of 20 g / h for a 1-hour addition esterification reaction. After the reaction, the material is cooled to 40 °C by a cooler and then separated by atmospheric distillation into C5 alkanes, acetic acid, and 1-methylbutyl acetate. The olefin conversion rate is 96.3%, and the selectivity of ethyl acetate is 99%. The purity of 1-methylbutyl acetate is greater than 99.5%, and the purity of C5 alkanes is 93.2%.

[0050] Example 3

[0051] Preparation of 1-methylpentyl acetate

[0052] 20 g of strongly acidic cation exchange resin D002-CC catalyst was loaded into the φ32×6×700 mm fixed-bed reactor 1, and the upper and lower ends of the catalyst loading section were filled with porcelain balls. The fixed-bed reactor was replaced with nitrogen to create a nitrogen environment. The reactor pressure was controlled at 1.5 MPa and the temperature was controlled at 125 °C. The glacial acetic acid raw material with a purity of 98% was fed into the fixed-bed reactor at a feeding rate of 30 g / h. The raw material was the C6 single-carbon component separated in Example 1 and was fed into the fixed-bed reactor at a feeding rate of 22 g / h for a 1-hour addition esterification reaction. After the reaction, the material was cooled to 40 °C by a cooler and then subjected to atmospheric distillation separation, separated into C6 alkane, acetic acid, and 1-methylpentyl acetate. The olefin conversion rate was 96.5%, and the ester selectivity was 99.3%. The purity of 1-methylpentyl acetate was greater than 99.5%, and the purity of C6 alkane was 93.1%.

[0053] Example 4

[0054] Preparation of 1-methylhexyl acetate

[0055] 20 g of strongly acidic cation exchange resin D072 catalyst was loaded into the φ32×6×700 mm fixed-bed reactor 1, and the upper and lower ends of the catalyst loading section were filled with porcelain balls. The fixed-bed reactor was replaced with nitrogen to create a nitrogen environment. The reactor pressure was controlled at 1.5 MPa and the temperature was controlled at 125 °C. The glacial acetic acid raw material with a purity of 98% was fed into the fixed-bed reactor at a feeding rate of 30 g / h. The raw material was the C7 single-carbon component separated in Example 1 and was fed into the fixed-bed reactor at a feeding rate of 24 g / h for a 1-hour addition esterification reaction. After the reaction, the material was cooled to 40 °C by a cooler and then subjected to atmospheric distillation separation, separated into C7 alkane, acetic acid, and 1-methylhexyl acetate. The olefin conversion rate was 97%, and the ester selectivity was 99.2%. The purity of 1-methylhexyl acetate was greater than 99.5%, and the purity of C7 alkane was 92.9%.

[0056] Example 5

[0057] Preparation of 1-methylheptyl acetate

[0058] Load 20 g of strongly acidic cation exchange resin D072 catalyst into the φ32×6×700 mm fixed-bed reactor 1, and fill the upper and lower ends of the catalyst loading section with porcelain balls. Replace the air in the fixed-bed reactor with nitrogen to create a nitrogen environment, control the reactor pressure at 2 MPa, and the temperature at 130 °C. Feed the glacial acetic acid raw material with a purity of 98% into the fixed-bed reactor at a feeding rate of 30 g / h. The raw material is the C8 single-carbon component separated in Example 1, and feed it into the fixed-bed reactor at a feeding rate of 25 g / h for 1 h of addition esterification reaction. After the reaction, the material is cooled to 40 °C by a cooler and then separated by atmospheric distillation into C8 alkane, acetic acid, and 1-methylheptyl acetate. The olefin conversion rate is 96.8%, and the ester selectivity is 99.3%. The purity of 1-methylheptyl acetate is greater than 99.5%, and the purity of C8 alkane is 91.4%.

[0059] Example 6

[0060] Preparation of 1-methyloctyl acetate

[0061] Load 20 g of strongly acidic cation exchange resin NKC-9 catalyst into the φ32×6×700 mm fixed-bed reactor 1, and fill the upper and lower ends of the catalyst loading section with porcelain balls. Replace the air in the fixed-bed reactor with nitrogen to create a nitrogen environment, control the reactor pressure at 2.5 MPa, and the temperature at 130 °C. Feed the glacial acetic acid raw material with a purity of 98% into the fixed-bed reactor at a feeding rate of 30 g / h. The raw material is the C9 single-carbon component separated in Example 1, and feed it into the fixed-bed reactor at a feeding rate of 26 g / h for 1 h of addition esterification reaction. After the reaction, the material is cooled to 40 °C by a cooler and then separated by atmospheric distillation into C9 alkane, acetic acid, and 1-methyloctyl acetate. The olefin conversion rate is 96.3%, and the ester selectivity is 99.1%. The purity of 1-methyloctyl acetate is greater than 99.5%, and the purity of C9 alkane is 90.06%.

[0062] Example 7

[0063] Preparation of 1-methyloctyl acetate

[0064] Load 20 g of strongly acidic cation exchange resin NKC-9 catalyst into the φ32×6×700 mm fixed-bed reactor 1. The upper and lower ends of the catalyst loading section are filled with porcelain balls. Replace the air in the fixed-bed reactor with nitrogen to create a nitrogen environment. Control the reactor pressure at 0.5 MPa and the temperature at 130 °C. Feed the glacial acetic acid raw material with a purity of 98% into the fixed-bed reactor at a feeding rate of 30 g / h. The raw material is the C9 single-carbon component separated in Example 1 and is fed into the fixed-bed reactor at a feeding rate of 26 g / h for a 1-hour addition esterification reaction. After the reaction, the material is cooled to 40 °C by a cooler and then subjected to atmospheric distillation separation, separated into C9 alkanes, acetic acid, and 1-methyloctyl acetate. The olefin conversion rate is 86.7%, and the ester selectivity is 90.5%. The purity of 1-methyloctyl acetate is greater than 99.5%, and the purity of C9 alkanes is 70.85%.

[0065] Example 8

[0066] Preparation of 1-methyloctyl acetate

[0067] Load 20 g of strongly acidic cation exchange resin NKC-9 catalyst into the φ32×6×700 mm fixed-bed reactor 1. The upper and lower ends of the catalyst loading section are filled with porcelain balls. Replace the air in the fixed-bed reactor with nitrogen to create a nitrogen environment. Control the reactor pressure at 2.5 MPa and the temperature at 170 °C. Feed the glacial acetic acid raw material with a purity of 98% into the fixed-bed reactor at a feeding rate of 30 g / h. The raw material is the C9 single-carbon component separated in Example 1 and is fed into the fixed-bed reactor at a feeding rate of 26 g / h for a 1-hour addition esterification reaction. After the reaction, the material is cooled to 40 °C by a cooler and then subjected to atmospheric distillation separation, separated into C9 alkanes, acetic acid, and 1-methyloctyl acetate. The olefin conversion rate is 76.2%, and the ester selectivity is 82.6%. The purity of 1-methyloctyl acetate is greater than 99.5%, and the purity of C9 alkanes is 57.6%.

[0068] Example 9

[0069] The difference from Example 6 is only that the reaction temperature is controlled at 160 °C.

[0070] The olefin conversion rate is 97.1%, and the ester selectivity is 98.2%. The purity of 1-methyloctyl acetate is 99.3%, and the purity of C9 alkanes is 90.05%.

[0071] Example 10

[0072] The difference from Example 6 is only that the reaction temperature is controlled at 120 °C.

[0073] The olefin conversion rate was 94.5%, and the ester selectivity was 99.2%. The purity of 1-methyloctyl acetate was 99.2%, and the purity of C9 alkane was 90.06%.

[0074] Example 11

[0075] The difference from Example 6 was that the loading amount of the strongly acidic cation exchange resin NKC-9 catalyst was 10 g.

[0076] The olefin conversion rate was 95.9%, and the ester selectivity was 99.3%. The purity of 1-methyloctyl acetate was 99.1%, and the purity of C9 alkane was 91.2%.

[0077] Example 12

[0078] The difference from Example 6 was that the loading amount of the strongly acidic cation exchange resin NKC-9 catalyst was 5 g.

[0079] The olefin conversion rate was 75.6%, and the ester selectivity was 99.5%. The purity of 1-methyloctyl acetate was 99.5%, and the purity of C9 alkane was 58.2%.

[0080] Example 13

[0081] The difference from Example 6 was that glacial acetic acid raw material with a purity of 98% was fed into the fixed-bed reactor at a feeding rate of 60 g / h

[0082] The olefin conversion rate was 80.7%, and the ester selectivity was 98.5%. The purity of 1-methyloctyl acetate was 98.9%, and the purity of C9 alkane was 65.17%.

[0083] Example 14

[0084] The difference from Example 6 was that the catalyst was D072.

[0085] The olefin conversion rate was 95.7%, and the ester selectivity was 99.2%. The purity of 1-methyloctyl acetate was greater than 99.5%, and the purity of C9 alkane was 90.01%.

[0086] Example 15

[0087] The raw material was a Fischer-Tropsch synthesis oil, and its composition was shown in Table 2. First, 1,2-propanediol was used as an extractant, and the mass ratio of the extractant to the oil was 3:1. The oxygen-containing compounds in the oil-washed naphtha were removed at normal temperature and pressure. After the oil-washed naphtha was deoxygenated, the oxide content was 820 ppm. The oil-washed naphtha was cut into single-carbon components of C9, C10, C11, C12, and C13 by atmospheric distillation, and the content of the single-carbon components was 99.1%.

[0088] Table 2

[0089]

[0090]

[0091] Example 16

[0092] Preparation of 1-methyloctyl acetate

[0093] It is only different from Example 6 in that the C9 raw material is the C9 single-carbon component prepared in Example 15.

[0094] The olefin conversion rate is 97.7%, and the ester selectivity is 99.3%. The purity of 1-methyloctyl acetate is 99.6%, and the purity of C9 alkane is 90.35%.

[0095] Example 17

[0096] Preparation of 1-methylundecyl acetate

[0097] The olefin conversion rate is 87.2%, and the ester selectivity is 95.4%. The purity of 1-methyloctyl acetate is 99.1%, and the purity of C10 alkane is 74.26%.

[0098] Example 18

[0099] Preparation of 1-methyltridecyl acetate

[0100] The olefin conversion rate is 67.5%, and the ester selectivity is 94.5%. The purity of 1-methyloctyl acetate is 99.2%, and the purity of C12 alkane is 59.1%.

[0101] Example 19

[0102] Preparation of 1-methyltetradecyl acetate

[0103] The olefin conversion rate is 65.3%, and the ester selectivity is 92.7%. The purity of 1-methyloctyl acetate is 99.1%, and the purity of C13 alkane is 54.6%.

[0104] Example 20

[0105] The Fischer-Tropsch synthesis oil-washed naphtha with the same composition as in Example 1 is directly cut into C5, C6, C7, C8, and C9 single-carbon components by atmospheric distillation without deoxygenation treatment.

[0106] The C9 single-carbon component among them is used for the preparation of 1-methyloctyl acetate, and the preparation method is exactly the same as that in Example 6. Finally, the olefin conversion rate is 97.2%, and the ester selectivity is 99.4%. The purity of 1-methyloctyl acetate is 92.7%, and the purity of C9 alkane is 91.3%.

[0107] Comparative Example 1

[0108] Charge 20 g of phosphotungstic acid catalyst (Hubei Kewode Chemical Co., Ltd.) into the fixed-bed reactor 1 with φ32×6×700 mm. Fill the upper and lower ends of the catalyst loading section with porcelain balls. Replace the air in the fixed-bed reactor with nitrogen to create a nitrogen environment. Control the reactor pressure at 1.7 MPa and the temperature at 120 °C. Feed the glacial acetic acid raw material with a purity of 98% into the fixed-bed reactor at a feeding rate of 30 g / h, and feed the raw materials C5, C6, and C7 into the fixed-bed reactor at a feeding rate of 22 g / h for a 1-hour addition esterification reaction. After the reaction, the material is cooled to 40 °C by a cooler and then subjected to atmospheric distillation separation, separated into alkanes, acetic acid, and carboxylic acid esters. The conversion rate of C5 olefins is 89.3%, and the ester selectivity is 98.2%; the conversion rate of C6 olefins is 85.6%, and the ester selectivity is 98.1%; the conversion rate of C7 olefins is 80.8%, and the ester selectivity is 98.8%.

[0109] Comparative Example 2

[0110] Charge 20 g of strongly acidic cation exchange resin NKC-9 catalyst into the fixed-bed reactor 1 with φ32×6×700 mm. Fill the upper and lower ends of the catalyst loading section with porcelain balls. Replace the air in the fixed-bed reactor with nitrogen to create a nitrogen environment. Control the reactor pressure at 2.5 MPa and the temperature at 130 °C. Feed the glacial acetic acid raw material with a purity of 98% into the fixed-bed reactor at a feeding rate of 30 g / h, and feed 1-nonene into the fixed-bed reactor at a feeding rate of 20 g / h for a 1-hour addition esterification reaction. After the reaction, the material is cooled to 40 °C by a cooler and then subjected to atmospheric distillation separation, separating acetic acid and 1-methyloctyl acetate. The olefin conversion rate is 75.3%, and the ester selectivity is 98.5%. The purity of 1-methyloctyl acetate is 99.7%.

[0111] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: Using the Fischer-Tropsch synthesis products as raw materials to prepare carboxylic acid esters with different carbon chain lengths. Since the Fischer-Tropsch synthesis products contain a large amount of odd-carbon α-olefins, carboxylic acid esters with different carbon chain lengths can be prepared, enriching the variety of carboxylic acid ester products. Moreover, using the Fischer-Tropsch synthesis products as raw materials has a lower cost. The alkane components in the raw materials dilute the reaction system, making the reaction easier to control, and solving the technical problem of high temperature control requirements for the system due to the poor thermal stability of the catalyst. Further, since the alkane components that are difficult to separate in the Fischer-Tropsch synthesis products do not participate in the reaction, they are easily separated from the carboxylic acid ester products after addition esterification, obtaining a single alkane product with higher value and solving the technical problem of difficult separation of alkanes and alkenes.

[0112] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing higher carbon esters of acetic acid from Fischer-Tropsch olefins, characterized in that, Including: Step S1: subject the Fischer-Tropsch synthesis product to rectifying cut to obtain Cn single-carbon components, where n is any one or more of integers from 5 to 13; Step S2: under the action of a catalyst, respectively introduce the Cn single-carbon components into a reactor to carry out a Markov addition reaction with acetic acid, and obtain the corresponding acetate through rectification; The said Step S1 includes: first remove the oxygen-containing compounds in the Fischer-Tropsch synthesis product to obtain deoxygenated refined Fischer-Tropsch synthesis oil, and then carry out rectifying cut on the deoxygenated refined Fischer-Tropsch synthesis oil; remove the oxygen-containing compounds in the Fischer-Tropsch synthesis product by extraction; the extractant is any one or more of 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol; the content of single-carbon olefins in the Cn single-carbon components is 50%-70%, and the content of single-carbon alkanes is 30%-50%.

2. The method according to claim 1, characterized in that, The Fischer-Tropsch synthesis product is washed oil naphtha.

3. The method according to claim 1, wherein The mass ratio of the extractant to the Fischer-Tropsch synthesis product is 3-4:

1.

4. The method according to claim 1, wherein The content of oxygen-containing compounds in the Cn single-carbon components is 3%-4.5%.

5. The method according to claim 1, characterized in that, The molar ratio of acetic acid to the single-carbon olefin is 1.5-4:

1.

6. The method according to claim 1, characterized in that, The catalyst is a strongly acidic cation exchange resin, and the strongly acidic cation exchange resin is selected from any one or more of D002-CC, D072, and NKC-9.

7. The method according to claim 1, wherein The reactor is a fixed-bed reactor.

8. The method according to claim 7, wherein Ceramic balls are installed at the bottom of the fixed-bed reactor, and the catalyst is arranged on the ceramic balls.

9. The method according to claim 8, characterized in that, Ceramic balls are also installed at the position between the upper wall of the reactor and above the catalyst.

10. The method according to claim 1, wherein The pressure of the Markov addition reaction is 1-3 MPa.

11. The method according to claim 1, wherein The temperature of the Markov addition reaction is 120-160 °C.

12. The method according to claim 1, wherein The time of the Markov addition reaction is 1-2 h.

13. The method according to claim 1, wherein The feed mass hourly space velocity of the Cn single-carbon component is 1-4 h -1 .

14. The method according to claim 1, wherein The Markov addition reaction is carried out in an inert gas atmosphere.

15. The method according to claim 1, wherein In Step S2, alkane by-products are separated out through the rectification.

16. The method according to claim 15, wherein The purity of the alkane by-products is ≥90%.

17. The method according to any one of claims 1 to 16, characterized in that, In Step S2, acetic acid is separated out by the rectification and introduced into the reactor as a reaction raw material.

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