CN107879877B

CN107879877B - Method and device for producing 2-butene from butane

Info

Publication number: CN107879877B
Application number: CN201610874774.6A
Authority: CN
Inventors: 王国清; 宋文波; 金立; 胡慧杰; 杜志国; 乔金樑
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2016-09-30
Filing date: 2016-09-30
Publication date: 2020-09-15
Anticipated expiration: 2036-09-30
Also published as: CN107879877A

Abstract

The invention relates to the field of producing 2-butene from butane, and discloses a method and a device for producing 2-butene from butane. The method comprises the following steps: (1) carrying out dehydrogenation reaction on butane to obtain a dehydrogenation product; (2) contacting said dehydrogenation product with maleic anhydride, said dehydrogenation product having C₄Carrying out copolymerization reaction on the lower end olefin and maleic anhydride; (3) carrying out gas-liquid separation on the product obtained in the step (2) to obtain a gas-phase product and a liquid-solid mixture; (4) carrying out gas phase separation on the gas phase product obtained in the step (3) to obtain 2-butene, and returning the obtained butane serving as a circulating material to the step (1); (5) and (4) separating the liquid-solid mixture obtained in the step (3), and obtaining a solid product which is a polymer containing maleic anhydride functional groups. Can realize the production of 2-butylene from butane and the production of copolymer containing maleic anhydride functional groups, and can be used as raw materials of functional materials.

Description

Method and device for producing 2-butene from butane

Technical Field

The invention relates to the field of producing 2-butene from butane, in particular to a method and a device for producing 2-butene from butane.

Background

Butane is one of products for industrially producing the carbon-four hydrocarbon substances, and the main application is used as fuel at present, so the economic value is too low. And if the C-C olefin, especially 2-butene, is converted, the C-C olefin can be used as a raw material for other synthesis reactions, and has wider application prospect.

The alkane can be subjected to catalytic dehydrogenation to obtain the alkene. For example, the dehydrogenation technology of propane and isobutane which are currently and internationally industrialized mainly includes an Oleflex process by UOP, a Star process by Phillips, a Catofin process by air product & Chemical, FDB-4 by Snamprogetti SPA, and a Linde process by Linde, etc.

The products of alkane dehydrogenation are mixtures, such as butane dehydrogenation, which typically includes C₁To C₄And hydrogen. And the 2-butene is required to be further purified by separation. However, the boiling point of some hydrocarbons in the butane-derived dehydrogenation product is low, and the volatility of each component in the butane-derived dehydrogenation product is very close, which makes the distillation separation of the hydrocarbons difficult and the operation cost is high. Although it is possible to extract and separate hydrocarbons by selecting an appropriate solvent according to the solubility of the hydrocarbon material, it is difficult to select a solvent having a high selectivity, a high solubility, a stable property, a low toxicity, a low corrosion, a low boiling point, and the like, for a mixture of hydrocarbons having a complicated content.

CN101781387A discloses a method for copolymerization of maleic anhydride/conjugated diene.

CN102212166B discloses a copolymerization reaction method of dicyclopentadiene and maleic anhydride, which has the advantages of simple reaction system, easy product separation, clean surface of the prepared polymer microsphere, uniform particle size, controllable morphology and good dispersibility under the condition of not increasing a stabilizer and a co-stabilizer.

CN102690393A discloses a copolymer containing functional groups, which is prepared from C5 mixed-maleic anhydride. The C5 mixture and maleic anhydride are copolymerized alternately to prepare the highly crosslinked copolymer containing functional groups in one step, thereby fully utilizing the olefin and the diene in the C5 mixture, and not concerning the condition of the low-carbon olefin below C5.

Therefore, to realize the more valuable utilization of butane, a resource utilization method which is simple, easy, convenient to operate and low in cost needs to be selected.

Disclosure of Invention

The invention aims to solve the problem of processing and utilizing butane and provides a method and a device for producing 2-butene from butane. The butane can be produced to obtain a 2-butene product, and in the process, the dehydrogenation product is subjected to copolymerization reaction, so that terminal olefin in the dehydrogenation product can be separated and polymerized to prepare a polymer containing a maleic anhydride functional group, and the polymer can be used as a raw material for producing functional materials.

In order to achieve the above object, the present invention provides a method for producing 2-butene from butane, comprising: (1) carrying out dehydrogenation reaction on butane in the presence of a dehydrogenation catalyst to obtain a dehydrogenation product; (2) contacting the dehydrogenation product with maleic anhydride in the presence of an initiator and an organic solvent, the dehydrogenation product having C₄The copolymerization reaction of partial or all of the lower terminal olefin and maleic anhydride; (3) carrying out gas-liquid separation on the product obtained in the step (2) to obtain a gas-phase product and a liquid-solid mixture; c in the gas-phase product based on the total weight of the gas-phase product₄The content of the lower terminal olefin is 1 wt% or less; (4) carrying out gas phase separation on the gas phase product obtained in the step (3) to obtain 2-butene, and returning the obtained butane serving as a circulating material to the butane in the step (1); (5) separating the liquid-solid mixture obtained in the step (3) to obtain a solid product and a liquid, wherein the solid product is a polymer containing maleic anhydride functional groups, and the liquid is returned to the organic solvent in the step (2); wherein the dehydrogenation product contains 78-85 wt% of C₄The following terminal olefins.

The invention also provides a device for producing 2-butene from butane, which comprises: dehydrogenation equipment, polymerization equipment, a gas-liquid separator, gas-phase separation equipment, carbon four-fraction separation equipment and a liquid-solid separator; wherein the content of the first and second substances,

the dehydrogenation equipment is used for carrying out dehydrogenation reaction on butane; the polymerization device is communicated with the dehydrogenation device and is used for carrying out copolymerization reaction on the dehydrogenation product discharged from the dehydrogenation device and maleic anhydride;

the gas-liquid separator is communicated with the polymerization equipment and is used for performing gas-liquid separation on a product discharged by the polymerization equipment to obtain a gas-phase product and a liquid-solid mixture;

the gas phase separation equipment is communicated with the gas-liquid separator and is used for separating the gas phase product to obtain a carbon four-fraction;

the four-carbon fraction separation equipment is communicated with the gas phase separation equipment and is used for separating the four-carbon fraction to obtain butane and 2-butene;

the four-carbon fraction separation device is communicated with the dehydrogenation device so as to recycle butane back to the dehydrogenation device; the liquid-solid separator is communicated with the gas-liquid separator and is used for separating the liquid-solid mixture to obtain a polymer containing a maleic anhydride functional group; the liquid-solid separator is in communication with the polymerization apparatus to return separated liquid.

According to the technical scheme, the butane is subjected to dehydrogenation reaction, copolymerization reaction, gas-liquid separation, gas-phase separation and liquid-solid separation in sequence, so that the butane can be effectively utilized to produce the 2-butene. Meanwhile, in the copolymerization reaction, the terminal olefin in the dehydrogenation product and the maleic anhydride can be subjected to copolymerization reaction, the reaction conversion rate of the copolymerization reaction reaches 85-90%, and the obtained copolymer can be used as a raw material for producing a functional material.

In the invention, on one hand, the butane can be used for producing 2-butene products, and on the other hand, the copolymer containing a maleic anhydride structure can be obtained without adding a coupling agent, and can be further used as a raw material for producing functional materials.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of a process for producing 2-butene from butane according to the present invention.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a method for producing 2-butene by butane, which comprises the following steps: (1) carrying out dehydrogenation reaction on butane in the presence of a dehydrogenation catalyst to obtain a dehydrogenation product; (2) contacting the dehydrogenation product with maleic anhydride in the presence of an initiator and an organic solvent, the dehydrogenation product having C₄The copolymerization reaction of partial or all of the lower terminal olefin and maleic anhydride; (3) carrying out gas-liquid separation on the product obtained in the step (2) to obtain a gas-phase product and a liquid-solid mixture; c in the gas-phase product based on the total weight of the gas-phase product₄The content of the lower terminal olefin is 1 wt% or less; (4) carrying out gas phase separation on the gas phase product obtained in the step (3) to obtain 2-butene, and adding the obtained butane serving as a circulating material into the butane in the step (1); (5) separating the liquid-solid mixture obtained in the step (3) to obtainA solid product and a liquid, wherein the solid product is a polymer containing maleic anhydride functional groups; the liquid is returned to the organic solvent in the step (2); wherein the dehydrogenation product contains 78-85 wt% of C₄The following terminal olefins.

The process flow diagram of the method provided by the invention is shown in figure 1.

Dehydrogenation reaction

According to the invention, the dehydrogenation reaction of step (1) is used to convert the starting butane into a dehydrogenation product containing 2-butene. Preferably, the dehydrogenation reaction temperature is 400-650 ℃, preferably 550-580 ℃; the dehydrogenation reaction pressure is less than 0.05MPa, preferably 0.01-0.05 MPa; the volume space velocity of butane is 200-2000 h^-1Preferably 500 to 600 hours^-1。

According to the present invention, preferably, the dehydrogenation catalyst comprises a support, an active component and an auxiliary agent; preferably, the carrier is alumina, the active component is a metal of the VIII group, and the auxiliary agent comprises carbon and at least one of tin, bismuth and boron; based on the total amount of the dehydrogenation catalyst, the content of the carrier is 90-99.5 wt%, the content of the active component is 0.001-2 wt%, and the content of the auxiliary agent is 0.001-5 wt%.

Preferably, the alumina is preferably gamma-alumina. Preferably, the active component is at least one of platinum, palladium, osmium and iridium, more preferably platinum.

Preferably, the carbon content is 0.001 to 5% by weight.

In the present invention, the dehydrogenation catalyst may be a commercially available catalyst, and may also be prepared by the following steps:

(i) soaking alumina in a solution containing an active component precursor and a solution containing at least one of tin, bismuth and boron in the same volume, drying and roasting in the air to obtain a catalyst roasted body;

(ii) roasting the catalyst roasted body in the presence of hydrogen and a carbon source to obtain a catalyst precursor;

(iii) and reducing the catalyst precursor in a reducing atmosphere to obtain the dehydrogenation catalyst.

In step (i) of the method for preparing a dehydrogenation catalyst in the present invention, the active component precursor is a compound capable of forming an active component in the finally prepared dehydrogenation catalyst, for example, the active component precursor may preferably be at least one of ammonium hexachloroplatinate, ammonium tetrachloroplatinate and chloroplatinic acid. The precursor containing at least one of tin, bismuth and boron is a compound capable of forming at least one of tin, bismuth and boron in the finally prepared dehydrogenation catalyst, for example, the precursor containing at least one of tin, bismuth and boron may be a nitrate, a chloride, a nitrate, a carbonate, a chloride, a phosphate, a sulfate, an acetate, a fluoride, a hydroxide of tin, bismuth or boron, or an acid or base containing tin, bismuth or boron, preferably bismuth nitrate or stannous chloride. Further, the impregnation in step (i) may be performed by sequentially mixing alumina with a solution containing an active component precursor, a solution containing a precursor of at least one of tin, bismuth, and boron in steps, or may be performed by preparing a solution mixture of a precursor of an active component and a precursor of at least one of tin, bismuth, and boron, and impregnating the alumina. The concentration of the solution containing the active component precursor can be 0.001-3 mol/L calculated by active component elements in the active component precursor, and the concentration of the solution containing the precursor of at least one of tin, bismuth and boron can be 0.001-3 mol/L calculated by the total amount of tin, bismuth or boron.

In the step (i) of the method for preparing the dehydrogenation catalyst, the impregnation can be carried out at 60-80 ℃ for 10-40 min. The drying can be carried out at 60-80 ℃ for 10-40 min, and can be rotary evaporation drying. The roasting in the air can be carried out for 2-4 h at the temperature of 100-500 ℃.

In step (ii) of the method for producing a dehydrogenation catalyst according to the present invention, the carbon source may be a gaseous or liquid hydrocarbon compound. When the carbon source is gaseous hydrocarbon, a mixed gas can be formed by hydrogen and the gaseous hydrocarbon, and the volume ratio of the hydrogen to the gaseous hydrocarbon in the mixed gas is (1-3): (1 to 6), for example, 2: 5. 1: 2; such as ethylene. When the carbon source is liquid hydrocarbon, the mixture can be mixed with hydrogen and liquid hydrocarbon, and the liquid hydrocarbon can be benzene and toluene. In the step (ii), the roasting temperature is 400-600 ℃, and the roasting time is 10-20 min.

In the step (iii) of the method for preparing the dehydrogenation catalyst, the reducing atmosphere is hydrogen, and the hydrogen is reduced for 0.5 to 2 hours at the temperature of 550 to 650 ℃.

In the present invention, the composition of the dehydrogenation catalyst can be determined by conventional elemental quantitative methods, such as X-ray fluorescence spectroscopy.

According to the invention, the dehydrogenation product obtained contains a large amount of C₄The lower terminal olefin may be further utilized by the subsequent copolymerization reaction. C in dehydrogenation product₄The lower terminal olefins may include ethylene, propylene, 1,3 butadiene, isobutylene, 1-butene. In addition, the dehydrogenation product may also contain n-butane and/or isobutane, which may be collectively referred to as butane. Further, the composition of the dehydrogenation product can be analyzed by gas chromatography using agilent 7890A Gas Chromatograph (GC). Preferably, the dehydrogenation product contains 17-22 wt% of isobutane, 17-22 wt% of n-butane, 5-7 wt% of 1-butene, 15-17 wt% of isobutene, 10-13 wt% of 2-butene, 0.1-2 wt% of 1, 3-butadiene, 20-23 wt% of hydrogen and 3-9 wt% of C based on the total weight of the dehydrogenation product₂And C₃And (4) components.

In a preferred embodiment of the invention, the dehydrogenation product may contain 17.57 wt.% isobutane, 17.68 wt.% n-butane, 6.06 wt.% 1-butene, 16.75 wt.% isobutene, 6.94 wt.% trans-2-butene, 5.28 wt.% cis-2-butene, 1.48 wt.% 1, 3-butadiene, 23 wt.% hydrogen, 6.24 wt.% C₂And C₃And (4) components.

In a preferred embodiment of the present invention, the dehydrogenation product may contain 21.18 wt% isobutane, 21.38 wt% n-butane, 5.25 wt% 1-butene, 16.60 wt% isobutene, 6.39 wt% trans-2-butene, 4.83 wt% cis-2-butene, 0.85 wt% 1, 3-butadiene, 21 wt% hydrogen, 2.52 wt% C₂And C₃And (4) components.

Copolymerization reaction

According to the invention, the step (2) is used for carrying out copolymerization reaction on the dehydrogenation product obtained in the step (1), which not only can be helpful for separating 2-butene product from the dehydrogenation product, but also can be used for separating C in the dehydrogenation product₄The copolymer obtained by copolymerization of the lower olefin component with maleic anhydride is used. Preferably, in step (2), the weight ratio of the dehydrogenation product to maleic anhydride is 0.3: 1 or more, preferably the weight ratio is (0.3-1): 1.

according to the present invention, in order to achieve more efficient copolymerization, it is preferable that the initiator is used in an amount of 0.01 to 30% by weight based on maleic anhydride in step (2).

According to the present invention, it is preferable that the initiator allows the dehydrogenation product to be more efficiently copolymerized with maleic anhydride, and it is preferable that the initiator is an azo compound or an organic peroxide, and it is preferable that the initiator is at least one selected from the group consisting of dibenzoyl peroxide, dicumyl peroxide, ditert-butyl peroxide, lauroyl peroxide, tert-butyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxide, azobisisobutyronitrile, and azobisisoheptonitrile. More preferably, the initiator is azobisisobutyronitrile and/or dibenzoyl peroxide.

According to the invention, the organic solvent is added in an amount sufficient to dissolve the initiator and the maleic anhydride, and preferably, in the step (2), the amount of the maleic anhydride is less than 30 wt% of the organic solvent, and preferably 5-25 wt%; more preferably 10 to 20% by weight.

According to the invention, the organic solvent may be used to dissolve the initiator and maleic anhydride, preferably, in step (2), the organic solvent is selected from alkanes, aromatic hydrocarbons and compounds of formula R₁-COO-R₂At least one of organic acid alkyl esters of (1), wherein R₁And R₂Is C₁～C₅Alkyl group of (1).

In the present invention, the organic acid alkyl ester is selected from at least one of but not limited to methyl formate, ethyl formate, methyl propyl ester, methyl butyl ester, methyl isobutyl ester, amyl formate, methyl acetate, ethyl ester, propylene acetate, butyl acetate, isobutyl acetate, sec-butyl acetate, amyl acetate, isoamyl acetate, benzyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, isobutyl butyrate, isoamyl isovalerate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, isoamyl benzoate, methyl phenylacetate and ethyl phenylacetate. More preferably, the organic acid alkyl ester is isoamyl acetate.

In the present invention, the alkane is selected from, but not limited to, at least one of propane, n-butane, isobutane, pentane, isopentane, n-hexane, isohexane, cyclohexane, n-heptane, n-octane, and isooctane.

In the present invention, the aromatic hydrocarbon is selected from, but not limited to, at least one of benzene, toluene, xylene, chlorobenzene, and bromobenzene.

According to the invention, the copolymerization reaction can realize selective utilization of C in dehydrogenation product₄The lower olefin component is copolymerized with maleic anhydride to obtain a raw material which can be further used as a functional material. Preferably, in the step (2), the copolymerization reaction temperature is 50-90 ℃, the copolymerization reaction pressure is 0-1 MPa, and the copolymerization reaction time is 0.5-12 h.

According to the invention, it is particularly preferred that the copolymerization is a free radical polymerization. The 1, 3-butadiene in the dehydrogenation product can be advantageously polymerized mainly in a 1,2 manner, and the side chain of the polymer chain segment can contain double bonds (double bonds at positions 3 and 4) and can be further reacted to form a cross-linked structure.

In a preferred embodiment, the copolymerization is carried out in a process comprising: and mixing the organic solvent, maleic anhydride and the initiator to form an organic reaction liquid, and then adding the dehydrogenation product into the organic reaction liquid to carry out copolymerization reaction.

In the present invention, the polymerization reactor for carrying out the copolymerization reaction may be a pressure-resistant reaction vessel with a stirrer and a jacket or a tubular reactor. The medium in the jacket is used for removing reaction heat and controlling the reaction temperature.

Separation of

In the present invention, after the copolymerization reaction is completed, the copolymerization reaction product needs to be separated to obtain a 2-butene product and a polymer product. Two-stage separation can be adopted: the first stage is gas-liquid separation to obtain gas phase product and liquid-solid mixture; the second stage comprises two processes, wherein one process is to carry out gas phase separation on the gas phase product to obtain 2-butene, and simultaneously obtain butane which is used as a circulating material to return to the dehydrogenation reaction; another process is that the liquid-solid mixture is separated into the polymer containing the maleic anhydride functional group and the liquid through liquid-solid separation.

First, gas-liquid separation

According to the present invention, the step (3) is for gas-liquid separating the product of the copolymerization reaction of the step (2).

In the present invention, the gas-liquid separation method may be flash separation. Preferably, the flash separation conditions are: reducing the pressure of the product of the copolymerization reaction to be below 0MPa at the temperature of more than 20 ℃, preferably 20-40 ℃, and reducing the pressure of C in the product to be below 0MPa₄The following hydrocarbon compounds were discharged to obtain the gas phase product.

In the present invention, the terminal olefin content in the gas product can be measured by gas chromatography using agilent 7890A Gas Chromatograph (GC). Wherein, C₄The content of the terminal olefin is 1 wt% or less.

In the invention, the flash separator can be a simple container with a jacket for controlling temperature, various internal components which are commonly known in the field and used for fully increasing the surface area of materials can be provided, and hot special material flow can be introduced from the bottom of the device to fully increase the heat exchange quantity.

Second, gas phase separation and liquid-solid separation

1. Gas phase separation

According to the invention, step (4) is used to subject the gas-phase product to a gas-phase separation from which 2-butene and butane are separated.

In the present invention, theThe gas phase separation process may be carried out by a rectifying column. Such as a carbon-three separation column, which may include primarily a compressor, a cryogenic separation system, a deethanizer, a depropanizer, a propylene rectification column, and a debutanizer; introducing the gas-phase product into a carbon-three separation tower for separation by using the feeding amount of 80-120 kg/h, the temperature of 30-50 ℃ and the pressure of 8-15 atm to obtain C₄The above fractions. The detailed description may be well known to those skilled in the art and will not be described herein.

Then C is mixed₄The above fractions are separated by any one or more of ordinary distillation, extractive distillation, adsorptive separation and chemical separation methods. For example, by extractive distillation, the japanese regen extractive distillation or the german krupp-cooper method may be used, and the specific embodiments are well known to those skilled in the art and will not be described herein. After extractive distillation, from C₄Butane and 2-butene are separated from the above fraction.

2. Liquid-solid separation

And carrying out liquid-solid separation on the liquid-solid mixture to obtain a polymer product.

The liquid-solid separation may be performed by centrifugation. The centrifugal separation conditions are as follows: under the condition that the centrifugal rotating speed is more than 4000rpm, the centrifugal separation time is more than 5min, for example, the centrifugal rotating speed is 4000-16000 rpm, and the centrifugal separation time is 5-20 min.

In the present invention, the centrifugal separator may be of any type, horizontal or vertical.

According to the invention, through liquid-solid separation, the liquid-solid mixed liquid is separated into a supernatant and a lower solid product; the clear solution is an organic solvent and can be removed and returned for the copolymerization reaction; the solid product is a polymer containing maleic anhydride functional groups. Preferably, the polymer is C in the dehydrogenation product₄Copolymers of terminal olefins with maleic anhydride; preferably, the content of the maleic anhydride structural unit in the polymer is 48 to 55 mol%. Preferably, the terminal olefin in the material is obtained by free radical polymerization with maleic anhydride. Maleic anhydride contained in the polymerThe structural units can be in the main chain, the side chain or the terminal group. The content of the maleic anhydride structural unit can be determined by¹H and¹³c nuclear magnetic measurement.

Preferably, the polymer may further contain a structural unit formed by at least one of ethylene, propylene, 1-butene, 1, 3-butadiene and isobutylene. The content of the above-mentioned structural units in the polymer may be determined by¹H and¹³c nuclear magnetic measurement. For example, the content of the above structural unit in the polymer may be 45 to 52 mol%.

Preferably, the polymer is a powder solid substance after being dried, and the average diameter of the particles can be 0.2-250 μm, preferably 0.2-2 μm. The average diameter of the polymer particles can be measured by scanning electron microscopy.

The reaction conversion rate of the copolymerization reaction can be determined by weighing the weight of the polymer obtained after the reaction.

The invention selectively converts C in the dehydrogenation product₄The following terminal olefin and maleic anhydride are preferably converted into a polymer containing a maleic anhydride functional group by radical copolymerization, and the polymer can be used as a raw material of a functional material and can be further used for preparing other high molecular materials.

In the present invention, the pressure refers to gauge pressure.

Fig. 1 is a schematic diagram of a preferred embodiment of the present invention, and the working process can be briefly described as follows:

continuously introducing butane into dehydrogenation equipment for dehydrogenation reaction, introducing an obtained dehydrogenation product into a polymerization reactor added with maleic anhydride, an initiator and an organic solvent, carrying out copolymerization reaction at a certain temperature, pressure and retention time, introducing the obtained product into a gas-liquid separator for gas-liquid separation, introducing the obtained gas-phase product into gas-phase separation equipment and carbon four-fraction separation equipment for separation to obtain a 2-butene product, and simultaneously returning the obtained butane to the dehydrogenation reaction; and (3) sending the liquid-solid product obtained by gas-liquid separation into a liquid-solid separator for liquid-solid separation to obtain a solid component which is a polymer, and obtaining liquid which is an organic solvent for recycling and copolymerization reaction.

the dehydrogenation equipment is used for carrying out dehydrogenation reaction on butane;

the polymerization device is communicated with the dehydrogenation device and is used for carrying out copolymerization reaction on the dehydrogenation product discharged from the dehydrogenation device and maleic anhydride;

the gas phase separation equipment is communicated with the gas-liquid separator and is used for separating the gas phase product to obtain a carbon four-fraction; the four-carbon fraction separation equipment is communicated with the gas phase separation equipment and is used for separating the four-carbon fraction to obtain butane and 2-butene;

In the device provided by the invention, the dehydrogenation equipment can be a fixed bed reactor.

In the device provided by the invention, the polymerization equipment can be a pressure-resistant reaction kettle or a tubular reactor with a stirring sleeve and a jacket, and is used for carrying out copolymerization reaction on pyrolysis gas and maleic anhydride in the presence of an initiator and an organic solvent to form C₄The copolymer of terminal olefin and maleic anhydride can be used as raw material of functional material.

In the device provided by the invention, the gas-liquid separator can be a flash separator. For separating the product of the polymerization reaction to obtain a gas phase product and a liquid-solid mixture.

In the device provided by the invention, the gas phase separation equipment can be a rectifying tower, such as a carbon three separation tower.

In the apparatus of the present invention, the carbon four-fraction separation device may be an extractive distillation column, and may be operated, for example, by the japanese extractive distillation method or the german krupp-cooper method.

The device provided by the invention is characterized in that the liquid-solid separator is a centrifugal separator which can be in any horizontal or vertical form and is used for separating the liquid-solid mixture to obtain a solid copolymer product in the liquid-solid mixture.

The present invention will be described in detail below by way of examples.

Analysis of dehydrogenation product composition analysis was performed by gas chromatography using agilent 7890A Gas Chromatograph (GC);

the terminal olefin content in the gas product was determined by gas chromatography using agilent 7890A Gas Chromatograph (GC);

the content of maleic anhydride structural units in the obtained polymer was determined by 1H and 13C nuclear magnetism;

the average diameter of the obtained polymer particles was measured by scanning electron microscopy;

the reaction conversion of the copolymerization reaction was determined by weighing the polymer after the reaction by calculating from the following formula:

reaction conversion (%) of copolymerization reaction [ (% of C in dehydrogenation product)₄Weight-polymerization of terminal olefins C in gas phase product₄Weight of terminal olefin)/C in the dehydrogenation product₄Weight of terminal olefin]×100％。

Example 1

This example illustrates the butane to 2-butene process of the present invention.

(1) 60g of gamma-alumina (Shandong aluminum industry) is soaked in 0.03mol/L chloroplatinic acid (national drug group chemical reagent Co., Ltd.) and 0.1mol/L bismuth nitrate (provided by Union chemical plant in Beijing) aqueous solution at 75 ℃ for 0.5h, wherein the volume of the solution is measured according to the mass content of Pt and Bi; then, drying the impregnated product by rotary evaporation for 0.5h at 75 ℃, placing the dried product into a muffle furnace, roasting for 3h in an air atmosphere at 450 ℃, and then impregnating the roasted product into 0.25mol/L stannous chloride (Tibet shin Fine chemical research institute) aqueous solution, wherein the volume of the solution is measured according to the mass content of Sn; then, after the catalyst is dried for 0.5h by rotary evaporation at 75 ℃, the catalyst is continuously roasted for 3h in an air atmosphere at 450 ℃ to obtain a catalyst roasted body.

The catalyst-calcined body is placed in a tube furnace in H₂And C₂H₄The volume ratio is 2: 5 for 15min in the mixed atmosphere, and the roasting temperature is 500 ℃, thus obtaining the catalyst precursor.

Reducing the catalyst precursor with hydrogen at 600 deg.C for 1h to obtain DHC-1 with Al₂O₃Pt/Sn-C-Bi, the content is as follows: 0.4 wt% Pt, 1.3 wt% Sn, 0.08 wt% C, 0.1 wt% Bi, and the balance Al₂O₃And (3) a carrier.

DHC-1 was charged to a fixed bed reactor in a 30mL volume. Introducing butane into a reactor for dehydrogenation reaction, wherein the volume space velocity is 500h^-1The reaction pressure was 0.01MPa and the reactor inlet temperature was 550 ℃.

The dehydrogenation product obtained was analyzed by HP7890 gas chromatography and contained the following: 21.18 wt% isobutane, 21.38 wt% n-butane, 5.25 wt% 1-butene, 16.60 wt% isobutene, 6.39 wt% trans-2-butene, 4.83 wt% cis-2-butene, 0.85 wt% 1, 3-butadiene, 21 wt% hydrogen, 2.52 wt% C₂And C₃And (4) components.

(2) Introducing 12kg of the dehydrogenation product into an organic reaction solution containing 20kg of maleic anhydride, 2.4kg of azobisisobutyronitrile and 100kg of isoamyl acetate, and carrying out copolymerization reaction for 8 hours at the copolymerization reaction pressure of 0.9MPa and the temperature of 70 ℃;

(3) introducing the copolymerization reaction product into a flash separator for separation at the temperature of 25 ℃ and under the pressure of 0.1MPa to obtain a gas-phase product and a liquid-solid mixture;

introducing the gas-phase product into a carbon-three separation tower for separation at the feed amount of 100kg/h, the temperature of 40 ℃ and the pressure of 11atm to obtain C₄Fraction (including n-butane, 40.40 wt%, isobutane)36.66 wt%, 2-butene, 22.94 wt%) was subjected to extractive distillation.

C is to be₄Extracting and rectifying the fraction by a Krupp-Cooper method to obtain the 2-butene with the purity of 99.5 percent by weight. (4) The resulting liquid-solid mixture was placed in a centrifugal separator (model TG18G, Ware scientific instruments, Beijing) and centrifuged at 4000rpm for 20min to obtain solid copolymer particles.

The maleic anhydride structure content of the solid copolymer particles was determined to be 45 mol%, and the average diameter of the particles was 0.2. mu.m.

The reaction conversion of the copolymerization reaction was 90%.

Example 2

(1) Soaking 60g of gamma-alumina in 0.03mol/L chloroplatinic acid, 0.25mol/L stannous chloride and 2mol/L boric acid (national drug group chemical reagent, Inc.) aqueous solution at 80 ℃ for 0.5h, wherein the volume of the solution is measured according to the mass content of Pt, Sn and B; and then drying the impregnated product at 70 ℃ for 0.5h by rotary evaporation, placing the dried product into a muffle furnace, and roasting the dried product in an air atmosphere at 500 ℃ for 3h to obtain a catalyst roasted body.

The catalyst-calcined body is placed in a tube furnace in H₂And C₂H₄Roasting for 12min in a mixed atmosphere with the volume ratio of 1:2, wherein the roasting temperature is 600 ℃, and obtaining the catalyst precursor.

Reducing the catalyst precursor with hydrogen at 620 ℃ for 1h to obtain DHC-2 with the composition of Al₂O₃The content of/Pt/Sn-C-B is as follows: 0.5 wt% Pt, 1.4 wt% Sn, 0.05 wt% C, 0.1 wt% Bi, and the balance Al₂O₃And (3) a carrier.

The fixed bed reactor was charged with DHC-2 in a 30mL volume. Introducing butane into a reactor for dehydrogenation reaction, wherein the volume space velocity is 600h^-1The reaction pressure was 0.05MPa, and the reactor inlet temperature was 580 ℃.

The dehydrogenation product obtained was analyzed by HP7890 gas chromatography and contained the following: 17.57 wt% isobutane, 17.68 wt% isobutane% of n-butane, 6.06% by weight of 1-butene, 16.75% by weight of isobutene, 6.94% by weight of trans-2-butene, 5.28% by weight of cis-2-butene, 1.48% by weight of 1, 3-butadiene, 23% by weight of hydrogen, 6.24% by weight of C₂And C₃And (4) components.

(2) Introducing 13kg of dehydrogenation product with the composition into an organic reaction solution containing 20kg of maleic anhydride, 2.4kg of azobisisobutyronitrile and 200kg of isoamyl acetate, and carrying out copolymerization reaction for 8h under the copolymerization reaction pressure of 1MPa and at the temperature of 75 ℃;

introducing the gas-phase product into a carbon-three separation tower for separation at the feed amount of 100kg/h, the temperature of 40 ℃ and the pressure of 11atm to obtain C₄The distillate (comprising isobutane, 37.01 wt%; n-butane, 37.24 wt%; 2-butene, 25.75 wt%) was subjected to extractive distillation.

C is to be₄Extracting and rectifying the fraction by a Krupp-Cooper method to obtain the 2-butene with the purity of 99.5 percent by weight.

(4) The resulting liquid-solid mixture was placed in a centrifugal separator and centrifuged at 4000rpm for 20min to obtain solid copolymer particles.

The maleic anhydride structure content of the solid copolymer particles was determined to be 52 mol%, and the average diameter of the particles was 200. mu.m.

The reaction efficiency of the copolymerization reaction was 85%.

The method of the invention realizes the production of 2-butene from butane. The copolymers which can also be obtained are used as starting materials for functional materials.

Claims

1. A process for producing 2-butene from butane, the process comprising:

(1) carrying out dehydrogenation reaction on butane in the presence of a dehydrogenation catalyst to obtain a dehydrogenation product;

(2) contacting the dehydrogenation product with maleic anhydride in the presence of an initiator and an organic solvent, the dehydrogenation product having C₄With maleic anhydride, part or all of the lower terminal olefinsCarrying out copolymerization reaction;

(3) carrying out gas-liquid separation on the product obtained in the step (2) to obtain a gas-phase product and a liquid-solid mixture; c in the gas-phase product based on the total weight of the gas-phase product₄The content of the lower terminal olefin is 1 wt% or less;

(4) carrying out gas phase separation on the gas phase product obtained in the step (3) to obtain 2-butene, and returning the obtained butane serving as a circulating material to the butane in the step (1);

(5) separating the liquid-solid mixture obtained in the step (3) to obtain a solid product and a liquid, wherein the solid product is a polymer containing a maleic anhydride functional group, and the liquid is returned to the organic solvent in the step (2);

wherein the dehydrogenation product contains 78-85 wt% of C₄The following terminal olefins.

2. The method according to claim 1, wherein in the step (1), the dehydrogenation reaction temperature is 400-650 ℃, the dehydrogenation reaction pressure is below 0.05MPa, and the volume space velocity of butane is 200-2000 h^-1。

3. The process of claim 1 or 2, wherein the dehydrogenation catalyst comprises a support, an active component, and a promoter; the active component is a VIII group metal, and the auxiliary agent comprises carbon and at least one of tin, bismuth and boron; based on the total amount of the dehydrogenation catalyst, the content of the carrier is 90-99.5 wt%, the content of the active component is 0.001-5 wt%, and the content of the auxiliary agent is 0.001-5 wt%.

4. The process of claim 3, wherein the support is alumina.

5. The process of claim 1, wherein in step (2), the weight ratio of dehydrogenation product to maleic anhydride is 0.3: 1 or more.

6. The method according to claim 5, wherein the weight ratio is (0.3-1): 1.

7. the method according to claim 1, wherein in the step (2), the copolymerization temperature is 50 to 90 ℃, the copolymerization pressure is 0 to 1MPa, and the copolymerization time is 0.5 to 12 hours.

8. The method according to claim 1, wherein in the step (2), the initiator is used in an amount of 0.01 to 30% by weight based on the maleic anhydride.

9. The method of claim 8, wherein the initiator is an azo compound or an organic peroxide.

10. The method of claim 9, wherein the initiator is selected from at least one of dibenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, lauroyl peroxide, t-butyl peroxybenzoate, diisopropyl peroxydicarbonate, azobisisobutyronitrile, and azobisisoheptonitrile.

11. The method according to claim 1, wherein, in the step (2), the amount of maleic anhydride used is 30% by weight or less of the organic solvent.

12. The method according to claim 11, wherein maleic anhydride is used in an amount of 5 to 25 wt% of the organic solvent.

13. The method according to claim 12, wherein maleic anhydride is used in an amount of 10 to 20 wt% of the organic solvent.

14. The process according to claim 1 or 13, wherein the organic solvent is selected from alkanes, aromatics and compounds of formula R₁-COO-R₂At least one of organic acid alkyl esters of (1), wherein R₁And R₂Is C₁～C₅Alkyl group of (1).

15. The process of claim 1 or 7, wherein the copolymerization is a free radical polymerization.

16. The method of claim 15, wherein the copolymerization is performed by a method comprising: and mixing the organic solvent, maleic anhydride and the initiator to form an organic reaction liquid, and then adding the dehydrogenation product into the organic reaction liquid to carry out copolymerization reaction.

17. The method of claim 1, wherein the polymer is C in the dehydrogenation product₄Copolymers of lower terminal olefins with maleic anhydride; the content of the maleic anhydride structural unit in the polymer is 48-52 mol%.

18. An apparatus for producing 2-butene from butane, comprising: dehydrogenation equipment, polymerization equipment, a gas-liquid separator, gas-phase separation equipment, carbon four-fraction separation equipment and a liquid-solid separator; wherein the content of the first and second substances,

the polymerization equipment is communicated with the dehydrogenation equipment and is used for carrying out copolymerization reaction on a dehydrogenation product discharged by the dehydrogenation equipment and maleic anhydride;

the four-carbon fraction separation device is communicated with the dehydrogenation device so as to recycle butane back to the dehydrogenation device;

the liquid-solid separator is communicated with the gas-liquid separator and is used for separating the liquid-solid mixture to obtain a polymer containing maleic anhydride functional groups; the liquid-solid separator is in communication with the polymerization apparatus to return separated liquid.