阅读说明：本技术 一种混合碳四氢甲酰化反应制备醛的方法 (Method for preparing aldehyde by mixed carbon-four hydroformylation reaction ) 是由 陈和 朱丽琴 包天舒 武陈 于 2018-08-27 设计创作，主要内容包括：一种混合碳四氢甲酰化反应制备醛的方法,包括：步骤S1、在第一催化剂的存在下使混合碳四和合成气在第一反应区接触进行氢甲酰化反应,得到含有正戊醛和2-甲基丁醛的第一反应产物；步骤S2、分离第一反应产物,得到正戊醛和2-甲基丁醛的混合物、未反应的原料以及含第一催化剂的物流；步骤S3、在第二催化剂的存在下使未反应的原料和合成气在第二反应区接触进行氢甲酰化反应得到含有3-甲基丁醛的第二反应产物,任选地,对第二反应产物进行纯化处理；所述混合碳四是指脱除了2-丁烯和1,3-丁二烯所得到的含1-丁烯和异丁烯的混合物。本发明通过分段反应的方式将1-丁烯和异丁烯分别进行氢甲酰化反应得到不同的产物,避免了提前进行1-丁烯和异丁烯的分离。(A method of preparing an aldehyde by a mixed carbo-tetrahydroformylation reaction, comprising: step S1, enabling the mixed C4 and the synthesis gas to contact in a first reaction area in the presence of a first catalyst to carry out hydroformylation reaction to obtain a first reaction product containing n-valeraldehyde and 2-methylbutyraldehyde; step S2, separating the first reaction product to obtain a mixture of n-valeraldehyde and 2-methylbutyraldehyde, unreacted raw materials and a material flow containing a first catalyst; step S3, in the presence of a second catalyst, enabling the unreacted raw materials and the synthesis gas to contact in a second reaction zone for hydroformylation reaction to obtain a second reaction product containing 3-methylbutyraldehyde, and optionally, purifying the second reaction product; the mixed C4 is a mixture containing 1-butene and isobutene obtained by removing 2-butene and 1, 3-butadiene. According to the invention, 1-butene and isobutene are respectively subjected to hydroformylation reaction in a sectional reaction mode to obtain different products, so that the advanced separation of 1-butene and isobutene is avoided.)

1. A method of preparing an aldehyde by a mixed carbo-tetrahydroformylation reaction, comprising:

step S1, enabling the mixed C4 and the synthesis gas to contact in a first reaction area in the presence of a first catalyst to carry out hydroformylation reaction to obtain a first reaction product containing n-valeraldehyde and 2-methylbutyraldehyde;

step S2, separating the first reaction product to obtain a mixture of n-valeraldehyde and 2-methylbutyraldehyde, unreacted raw materials and a material flow containing a first catalyst;

step S3, in the presence of a second catalyst, enabling the unreacted raw materials and the synthesis gas to contact in a second reaction zone for hydroformylation reaction to obtain a second reaction product containing 3-methylbutyraldehyde, and optionally, purifying the second reaction product;

the mixed C4 is a mixture containing 1-butylene and isobutylene obtained by removing 2-butylene and 1, 3-butadiene from the C four component.

2. The process according to claim 1, wherein the first catalyst is a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine-based ligand; the second catalyst is one or more selected from the group consisting of a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine ligand, a rhodium-phosphine complex catalyst formed from a rhodium compound and a phosphite ligand, and a rhodium-phosphine complex catalyst formed from a rhodium compound and a phosphate ligand.

3. The process according to claim 1 or 2, wherein the first catalyst is a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine-based ligand, and the second catalyst is a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine-based ligand; the conditions of the first reaction zone include: at a temperature of 60-120 ℃, preferably 88-100 ℃, and/or at a pressure of 0.5-2.0MPa, preferably 0.8-2.0 MPa; the conditions of the second reaction zone include: the temperature is 60-120 deg.C, preferably 90-110 deg.C, and/or the pressure is 0.5-4MPa, preferably 2.0-4.0 MPa.

4. The process according to claim 1 or 2, wherein the first catalyst is a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine-based ligand; the second catalyst is selected from a rhodium-phosphine complex catalyst generated by a rhodium compound and a phosphite ligand, and/or a rhodium-phosphine complex catalyst generated by a rhodium compound and a phosphate ligand; the conditions of the first reaction zone include: at a temperature of 60-120 ℃, preferably 88-100 ℃, and/or at a pressure of 0.5-2MPa, preferably 0.8-2.0 MPa; the conditions of the second reaction zone include: the temperature is 60-120 deg.C, preferably 70-100 deg.C, and the reaction pressure is 0.5-4MPa, preferably 0.8-2.0 MPa.

5. The method according to any one of claims 2 to 4, characterized in thatCharacterized in that the rhodium compound is selected from one or more of rhodium acetylacetonate dicarbonyl, rhodium trioxide, dodecacarbonyltetrarhodium, hexadecahonylhexarhodium, rhodium nitrate and rhodium acetate; and/or, the hydrocarbyl phosphine ligand has the structure

6. The method according to any one of claims 1-5, wherein: the content of 2-butene in the mixed C4 is less than 1 wt%, preferably less than 0.1 wt%.

7. The method of any one of claims 1-6, wherein the isobutylene content of the mixed C4 is greater than 10 wt%.

8. The process according to any one of claims 1 to 7, characterized in that the content of 1-butene in the unreacted feedstock is less than 1.5 wt%, preferably less than 1.0 wt%, and the content of 2-methylbutanal is less than 500ppm, preferably less than 200 ppm.

9. A process according to any one of claims 1 to 8, characterised in that the stream comprising the first catalyst is recycled to the first reaction zone.

10. The process of any one of claims 1 to 9, wherein the reaction apparatus of the first reaction zone and the reaction apparatus of the second reaction zone are each independently a single reactor or a plurality of reactors in series, wherein the plurality of reactors in series are the same or different, and wherein the reactors are tank reactors or column reactors.

Technical Field

The invention relates to a method for preparing aldehyde by mixed carbon four hydroformylation.

Background

The hydroformylation of olefins with synthesis gas over a catalyst to produce aldehydes having one more carbon atom than the olefin is a well known process.

The hydroformylation reaction of olefins without isomers, such as ethylene and propylene, is relatively simple, and for olefins with more than four carbon atoms, because different isomers exist, the hydroformylation reaction conditions of various isomers are different, the structures of aldehyde products are also different, and the separation of the hydroformylation product aldehyde of some isomers is difficult, so that for olefins with more than four carbon atoms, the mixed olefins with more than four carbon atoms are not suitable for being simultaneously reacted in the same reaction zone, and need to be separated before the reaction.

Taking mixed C.sub.four as an example, possible compositions are 1-butene, trans-2-butene, cis-2-butene, isobutene, 1, 3-butadiene and butane. At present, the industrial separation of 1, 3-butadiene from four carbon components is well established, and for isobutene, a method for converting isobutene into methyl tert-butyl ether is adopted to realize the separation of isobutene from mixed four carbon components. The product of the mixed C.sub.D with isobutylene removed is generally referred to as C.sub.D.sub.etherate. However, in recent years, due to the safety problem of methyl t-butyl ether, some developed countries have legislation that prohibits the addition of methyl t-butyl ether to gasoline, rendering isobutylene a less important use, and the manner in which isobutylene is converted to methyl t-butyl ether has been limited. In this context, the composition of mixed C.sub.four would be 1-butene, trans-2-butene, cis-2-butene, isobutene and butane.

The boiling points of the components in the mixed carbon four can be seen in the following table:

as can be seen from the boiling points of the components in the mixed C4, the 2-butene has large difference with other components, and the 2-butene can be separated from the mixed C4 by the conventional rectification method, however, the boiling points of the isobutene and the 1-butene are very close, and the isobutene and the 1-butene are difficult to separate by the conventional method. Therefore, how to realize the effective utilization of the C4 resource and obtain the C4 reaction product with high purity is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a method for preparing aldehyde by mixed carbon four hydroformylation, which realizes the generation of different high-purity aldehyde products in two reaction zones by using a mode of carrying out reaction on raw materials in a subarea manner.

The invention is realized by the following technical scheme: a method of preparing an aldehyde by a mixed carbo-tetrahydroformylation reaction, comprising:

step S1, enabling the mixed C4 and the synthesis gas to contact in a first reaction area in the presence of a first catalyst to carry out hydroformylation reaction to obtain a first reaction product containing n-valeraldehyde and 2-methylbutyraldehyde;

step S2, separating the first reaction product to obtain a mixture of n-valeraldehyde and 2-methylbutyraldehyde, unreacted raw materials and a material flow containing a first catalyst;

step S3, in the presence of a second catalyst, enabling the unreacted raw materials and the synthesis gas to contact in a second reaction zone for hydroformylation reaction to obtain a second reaction product containing 3-methylbutyraldehyde, and optionally, purifying the second reaction product;

the mixed C4 is a mixture containing 1-butene and isobutene obtained by removing 2-butene and 1, 3-butadiene.

The synthesis gas is a mixed gas of hydrogen and carbon monoxide, preferably, the molar ratio of hydrogen to carbon monoxide is 1: 10-10: 1, preferably 1: 2-10: 1.

According to a preferred embodiment of the present invention, the first catalyst is a rhodium-phosphine complex catalyst generated from a rhodium compound and a hydrocarbyl phosphine-based ligand; the second catalyst is one or more selected from the group consisting of a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine ligand, a rhodium-phosphine complex catalyst formed from a rhodium compound and a phosphite ligand, and a rhodium-phosphine complex catalyst formed from a rhodium compound and a phosphate ligand.

According to a preferred embodiment of the present invention, the first catalyst and/or the second catalyst are present in the form of a solution, and the solvent for dissolving the first catalyst and the second catalyst may be selected from one or more of alkanes having 1 to 30 carbon atoms, aromatic hydrocarbons, alcohols, ketones, ethers, esters, sulfoxides, and phenols.

According to a preferred embodiment of the present invention, the first catalyst is a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine-based ligand, and the second catalyst is a rhodium-phosphine complex catalyst formed from a rhodium compound and a hydrocarbyl phosphine-based ligand; the conditions of the first reaction zone include: at a temperature of 60-120 ℃, preferably 88-100 ℃, and/or at a pressure of 0.5-2MPa, preferably 0.8-2.0 MPa; the conditions of the second reaction zone include: the temperature is 60-120 deg.C, preferably 90-110 deg.C, and/or the pressure is 0.5-4MPa, preferably 2.0-4.0 MPa.

According to a preferred embodiment of the present invention, the first catalyst is a rhodium-phosphine complex catalyst generated from a rhodium compound and a hydrocarbyl phosphine-based ligand; the second catalyst is selected from a rhodium-phosphine complex catalyst generated by a rhodium compound and a phosphite ligand, and/or a rhodium-phosphine complex catalyst generated by a rhodium compound and a phosphate ligand; the conditions of the first reaction zone include: at a temperature of 60-120 ℃, preferably 88-100 ℃, and/or at a pressure of 0.5-2MPa, preferably 0.8-2.0 MPa; the conditions of the second reaction zone include: at a temperature of 60-120 ℃, preferably 70-100 ℃, and/or at a pressure of 0.5-4Mpa, preferably 0.8-2.0 Mpa.

According to a preferred embodiment of the invention, the rhodium compound is selected from one or more of rhodium acetylacetonate dicarbonyl, rhodium trioxide, dodecacarbonyltetrarhodium, hexadecahonylhexarhodium, rhodium nitrate and rhodium acetate.

According to the bookIn a preferred embodiment of the present invention, the hydrocarbyl phosphine ligand has the structure

Wherein R is₁、R₂And R₃Each independently selected from the group consisting of H, alkyl, aryl, aralkyl, and alkaryl.

According to a preferred embodiment of the invention, the phosphite ligand is selected from one or more of the group consisting of monophosphites, diphosphites and triphosphites.

According to a preferred embodiment of the invention, the 2-butene content of the mixed C4 is below 1 wt%, preferably below 0.1 wt%.

According to a preferred embodiment of the present invention, the content of isobutylene in the mixed C4 is 10 wt% or more.

According to a preferred embodiment of the invention, the unreacted starting material is essentially isobutene, which also contains small amounts of unreacted 1-butene, and the inert component butane. The unreacted feed has a 1-butene content of less than 1.5 wt%, preferably less than 1.0 wt%, and a 2-methylbutanal content of less than 500ppm, preferably less than 200 ppm.

According to a preferred embodiment of the invention, said stream comprising the first catalyst is recycled to the first reaction zone. The first catalyst-containing stream includes a first catalyst and a solvent that dissolves the first catalyst.

According to a preferred embodiment of the present invention, the second reaction product is separated to obtain unreacted carbon four (inert components methane and a small amount of isobutylene), a stream containing the second catalyst, and 3-methylbutyraldehyde, the stream containing the second catalyst is recycled to the second reaction zone, and 3-methylbutyraldehyde is withdrawn as a product of the second reaction zone. The second catalyst containing stream includes the second catalyst and a solvent that dissolves the first catalyst.

The inventors have found that, when a rhodium-phosphine complex catalyst is used which is formed from a rhodium compound and a hydrocarbyl phosphine ligand, under the same conditions, the reaction rate of 1-butene is high, and the hydroformylation reaction can be carried out under a low partial pressure of carbon monoxide and hydrogen, but the reaction is hardly carried out under the conditions for 2-butene and isobutene. The rhodium-phosphine complex catalyst generated by the rhodium compound and the phosphite ligand and/or the rhodium-phosphine complex catalyst generated by the rhodium compound and the phosphate ligand, whether 1-butene, 2-butene or isobutene, can obtain higher hydroformylation reaction speed under lower partial pressure of carbon monoxide and hydrogen. The hydroformylation products of 1-butene and 2-butene are n-valeraldehyde and 2-methylbutyraldehyde, and the specific structure of isobutylene is such that the hydroformylation product is almost 100% of 3-methylbutyraldehyde. However, the inventors have found that both 2-methylbutyraldehyde and the hydroformylation product of isobutylene, 3-methylbutyraldehyde, are close in boiling point and are difficult to separate by conventional rectification means. Further, since the reaction rates of 2-butene and isobutylene are relatively close to each other under the same conditions, in order to maintain the purity of 3-methylbutyraldehyde which is an isobutylene product at a high level, in the present invention, 2-butene is separated from mixed C.sub.C.sub.C.sub.C.to obtain mixed C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.sub.C.. In the invention, 1-butene and isobutene react in different reaction zones by reacting in two stages under different reaction conditions and/or different catalysts, so that high-purity products are respectively obtained. Since the reaction speed of 1-butene is relatively fast, 1-butene can also react at a relatively fast speed to generate a small amount of 2-methylbutyraldehyde under the reaction conditions of isobutene, so in order to avoid the influence of 2-methylbutyraldehyde on isobutene products, in the invention, the reaction conditions are controlled to achieve a relatively high conversion rate of 1-butene in the first reaction zone, preferably the conversion rate of 1-butene in the first reaction zone is more than 97%, preferably more than 98.3%. And, the first reaction product is separated, i.e., unreacted starting material is separated from the product aldehyde, prior to hydroformylation of the isobutylene in the second reaction zone. Thereby controlling the higher purity of the 3-methyl butyraldehyde.

According to a preferred embodiment of the present invention, the separation of the first reaction product and the second reaction product can be carried out in a separation manner customary to the person skilled in the art, for example in a flash and/or rectification manner.

According to a preferred embodiment of the present invention, the reaction apparatus of the first reaction zone and the reaction apparatus of the second reaction zone are each independently a single reactor or a plurality of reactors connected in series, wherein the plurality of reactors connected in series are the same or different, and the reactors are tank reactors or tower reactors.

The method for producing different aldehyde products by two reaction zones is realized by utilizing different hydroformylation reaction characteristics of 1-butene and isobutene and adopting a mode of reacting the 1-butene and the isobutene in a partition manner; by means of an intermediate separation between the two reaction zones, a process is achieved for producing different aldehydes of high purity from the two reaction zones.

According to the invention, 1-butene and isobutene are respectively subjected to hydroformylation reaction in a sectional reaction mode to obtain different products, so that the advanced separation of 1-butene and isobutene is avoided.

Drawings

FIG. 1 is a schematic flow diagram of the present invention.

FIG. 2 is a schematic flow diagram of a first reaction zone in example 1 of the present invention.

FIG. 3 is a schematic flow diagram of a second reaction zone of example 1 of the present invention.

Detailed Description

The present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

The work flow diagram of the plant for the preparation of aldehydes by mixed C-C hydroformylation according to the invention is shown in block diagram form in FIG. 1, in which, for the sake of clarity, FIG. 1 omits the conventional elements required in the industrial plant, such as valves, pumps, heat exchangers, etc., and these conventional elements can be implemented in accordance with the prior art.

As shown in fig. 1: the mixed C-four stream 1, the synthesis gas 2 and the first catalyst solution stream 5 from the intermediate separation zone 102 enter a first reaction zone 101, and 1-butene in the first reaction zone 101 is subjected to hydroformylation reaction under the action of a first catalyst to generate n-valeraldehyde and 2-methylbutyraldehyde. The gas phase stream 4 produced from the first reaction zone 101 is removed from the first reaction zone 101 as off-gas or passed to other units for further processing. The liquid phase product 3 of the first reaction zone enters an intermediate separation zone 102, unreacted raw materials (including isobutene and butane) and product valeraldehyde (n-valeraldehyde and 2-methylbutyraldehyde) are separated from the first catalyst solution 5 in the intermediate separation zone 102, the unreacted raw materials (isobutene and butane) and the product valeraldehyde (n-valeraldehyde and 2-methylbutyraldehyde) are sent to a separation section 103 of the intermediate separation zone, and the first catalyst solution 5 returns to the first reaction zone. In the separation section 103 of the intermediate separation zone, the four carbon streams 8 (isobutylene and butane) are separated from the valeraldehyde 7 (n-valeraldehyde and 2-methylbutyraldehyde), and the four carbon streams 8 (isobutylene and butane) enter the second reaction zone 201 to react with the synthesis gas 9 and the catalyst solution 12 from the post-separation zone 202 in the second reaction zone 201. The gas phase stream 11 obtained from the second reaction zone 201 is discharged as off-gas or sent to other units for further processing. The liquid phase material flow 10 obtained from the second reaction area 201 enters the post-separation area 202, a small amount of unreacted isobutene, butane and product valeraldehyde are separated from the second catalyst solution 12 in the post-separation area 202, a small amount of unreacted isobutene, butane and product valeraldehyde are sent to the separation section 203 of the post-separation area, the second catalyst solution 12 returns to the second reaction area 201, in the separation section 203 of the post-separation area, the carbon four material flow 14 (a small amount of isobutene and butane) is separated from the 3-methyl butyraldehyde 15, the carbon four material flow 14 (a small amount of isobutene and butane) is taken as a byproduct, and the 3-methyl butyraldehyde 15 can be further refined to obtain the high-purity 3-methyl butyraldehyde if necessary.

The 1-butene content and the 2-methylbutanal content of the carbon four stream 8 (isobutylene and butane) entering the second reaction zone 201 are controlled. As noted above, due to the difficulty in separating the 2-methylbutyraldehyde from the 3-methylbutyraldehyde, the 1-butene content of the carbon four stream 8 entering the second reaction zone should be controlled to be less than 1.5 wt%, preferably less than 1.0 wt%, and the 2-methylbutyraldehyde content should be controlled to be less than 500ppm, preferably less than 200 ppm.

The first reaction zone 101 and the second reaction zone 201 may be a single tank reactor or a tower reactor, or may be a combination of a plurality of different or identical reactors connected together.