A production process for the dehydrochlorination of 1,1,1,3-tetrachloropropane

Abstract

The present invention belongs to the technical field of chemical synthesis, and particularly relates to a production process for dehydrochlorination of 1,1,1,3-tetrachloropropane. The process comprises the following steps: (1) modifying γ-alumina powder with an amino-silane coupling agent to prepare modified γ-alumina powder; (2) preparing modified γ-alumina powder loaded with a trivalent metal salt by an impregnation process to obtain a catalyst; (3) activating the catalyst; (4) adjusting the reaction temperature and pressure, and introducing 1,1,1,3-tetrachloropropane for dehydrochlorination reaction to obtain 1,1,3-trichloropropene. This catalyst attaches the active components to the solid matrix, not only reducing phenomena such as chlorine absorption and coking, but also further improving the catalyst stability on the basis of high conversion rate and selectivity, and avoiding the occurrence of side reactions.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical synthesis, and particularly relates to a production process for dehydrochlorination of 1,1,1,3 - tetrachloropropane. Background Art

[0002] Relevant research shows that a chain reaction initiated by one chlorine (bromine) atom in the ozone layer can approximately destroy 100,000 ozone molecules. Generally, when a chlorofluorocarbon (bromofluorocarbon) releases a chloride ion, the remaining group can still react with substances such as oxygen, causing all the chlorine atoms (bromine atoms) in the compound to be released in the form of Cl (Br) free radicals, and the reaction of destroying the ozone layer keeps cycling. These substances that damage the atmospheric ozone layer and endanger the living environment of the earth's organisms are called ozone - depleting substances.

[0003] In addition, global warming is another major problem faced by mankind. Although the ozone - depletion potential value of hydrofluorocarbons is zero, their global warming potential value is very high, and they belong to greenhouse - effect substances. The main reason for the greenhouse effect of hydrofluorocarbons is that they absorb infrared rays of a certain wavelength, absorb the infrared energy emitted by the earth, and then re - radiate this energy back to the earth, increasing the temperature of the earth's surface. In addition, some hydrofluorocarbons have a long chemical lifespan, generally do not decompose in the troposphere, accumulate in the earth's atmosphere, and disrupt the thermal radiation balance of the earth.

[0004] At present, the widely used refrigerant 1,1,1,2 - tetrafluoroethane has entered the process of being phased out due to its high global warming potential value. While 2,3,3,3 - tetrafluoropropene has no flash point, its auto - ignition point is 405 °C, and it has good stability. The risk of harmful substance HF generated by the combustion and thermal decomposition of 2,3,3,3 - tetrafluoropropene in automotive air conditioners is at the same order of magnitude as that of 1,1,1,2 - tetrafluoroethane, belonging to a safe and reliable refrigerant. Moreover, the toxicity of 2,3,3,3 - tetrafluoropropene is lower than that of 1,1,1,2 - tetrafluoroethane, belonging to low - toxicity substances. More importantly, 2,3,3,3 - tetrafluoropropene has good compatibility with most organic polymers, and its compatibility is equivalent to that of 1,1,1,2 - tetrafluoroethane. 2,3,3,3 - tetrafluoropropene has no activity and corrosiveness to metal materials such as carbon steel, stainless steel, copper, and brass. At the same time, 2,3,3,3 - tetrafluoropropene has good miscibility with common lubricating oils, and its applicable fields are very wide.

[0005] 1,1,2,3 - Tetrachloropropene is an important precursor of 2,3,3,3 - tetrafluoropropene and needs to be prepared by dehydrochlorination, chlorination and other reactions of 1,1,1,3 - tetrachloropropane. At present, the dehydrochlorination process of 1,1,1,3 - tetrachloropropane usually adopts a homogeneous reaction process in the liquid phase. CN 119241329 A stirs and refluxes tetrachloropropane and sodium hydroxide solution under normal pressure and at 40 - 100 °C. After the reaction, the reaction solution is cooled to room temperature and separated by a separating funnel. The obtained oil phase is rectified to obtain trichloropropene. An improver can also be added to the reaction system, and the improver is a complex system composed of a metal salt and a bidentate phosphine ligand or a metal composite oxide. Although the method of this invention has fewer reaction steps, it uses strong alkaline substances, has high requirements for equipment, low product selectivity, low reaction efficiency, and a large amount of waste salt, making it difficult to be widely used. Summary of the Invention

[0006] In order to solve the problems existing in the background technology, the purpose of the present invention is to provide a method for highly selectively preparing 1,1,3 - trichloropropene by dehydrochlorination of 1,1,1,3 - tetrachloropropane. 1,1,3 - trichloropropene can be prepared into 1,1,2,3 - tetrachloropropene through chlorination and dehydrochlorination processes. 1,1,1,3 - tetrachloropropane reacts with a catalyst under certain conditions to prepare 1,1,3 - trichloropropene, and on the basis of increasing the conversion rate of 1,1,1,3 - tetrachloropropane, the selectivity of the target product is further increased.

[0007] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0008] A production process for dehydrochlorination of 1,1,1,3 - tetrachloropropane, comprising the following steps:

[0009] (1) Modify γ - alumina powder with an amino - silane coupling agent to obtain modified γ - alumina powder; the mass ratio of γ - alumina powder to the amino - silane coupling agent is 1:(0.01 - 0.2);

[0010] (2) Prepare a modified γ - alumina powder loaded with a trivalent metal salt by an impregnation process to obtain a catalyst;

[0011] (3) Activate the catalyst;

[0012] (4) Adjust the reaction temperature and pressure, introduce 1,1,1,3 - tetrachloropropane for dehydrochlorination reaction to obtain 1,1,3 - trichloropropene.

[0013] γ-aluminum oxide powder has a high specific surface area and a rich pore structure, so the loaded metal ions are more likely to be dispersed on its surface. Due to its adjustable pore structure, the diffusion resistance of the loaded metal ions is reduced, and the occurrence of unnecessary pore blockage is avoided. At the same time, the adjustable surface acidity of γ-aluminum oxide powder plays a stabilizing role in the catalyst used in the dehydrochlorination process and also has an important impact on the carbon deposition behavior occurring in the catalytic reaction. Using γ-aluminum oxide powder as the carrier can greatly improve the adhesion efficiency of trivalent metal salts.

[0014] However, relying solely on the physical properties of γ-aluminum oxide powder, its adhesion is limited. To improve the adhesion stability, the present invention adds an amino coupling agent to modify it. On the one hand, the siloxane bond in the coupling agent can undergo a hydrolysis reaction with the hydroxyl groups on the surface of γ-aluminum oxide powder, overcoming the physical forces such as van der Waals force and electrostatic attraction existing between γ-aluminum oxide particles, and improving the dispersion performance of the powder. On the other hand, since the coupling agent contains various amino groups, it can complex with trivalent metal salts, improving the stability of trivalent metal salts. Compared with divalent metal ions such as copper, zinc, magnesium, and palladium, trivalent metal salts are more stable; more importantly, trivalent metal salts are more likely to undergo a complexation reaction with polyamines, improving the stability of the catalyst.

[0015] Further, the specific surface area of the γ-aluminum oxide powder described in step (1) is 200 - 300 m 2 / g, the average pore diameter is 5 - 12 nm, and the pore volume is 0.4 - 1 cm 3 / g. The diameter of the powder particles is not particularly limited, and generally those within 0.2 - 3 mm are acceptable. An appropriate specific surface area can not only load more active components but also be evenly loaded by the silane coupling agent. And a larger pore diameter provides more space for carbon deposition and trivalent metal ion active components, improving the dehydrochlorination performance of the catalyst.

[0016] Further, the amino-containing silane coupling agent described in step (1) is at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylethyldimethoxysilane, γ-aminopropylethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-divinyltriaminepropylmethyldimethoxysilane, 3-divinyltriaminepropyltrimethoxysilane, 3-divinyltriaminepropyltriethoxysilane.

[0017] The complexation principle of amino silane coupling agents is mainly based on the coordination between trivalent metal ions and amino silane coupling agent molecules. Amino silane coupling agents contain multiple electron-donating groups - amino groups, and these electron-donating groups have lone pairs of electrons that can form coordination bonds with trivalent metal ions. Aqueous solutions of trivalent metal salts are acidic. During the complexation process, the trivalent metal ions act as central ions, and the amino silane coupling agent acts as a ligand to surround the trivalent metal ions within the molecular structure of the complexing agent through the formation of coordination bonds. Amino coupling agents have strong complexing abilities and can form stable complexes with trivalent metal ions, remaining stable even within a relatively wide pH range. Through complexation, the trivalent metal ions are stably loaded onto the alumina support, enhancing the catalyst stability.

[0018] Furthermore, using the prepared 1,1,3-trichloropropene as a raw material, it is chlorinated with chlorine to prepare 1,1,1,2,3-pentachloropropane; using 1,1,1,2,3-pentachloropropane as a raw material, hydrogen chloride is removed to prepare 1,1,2,3-tetrachloropropene. The process of removing hydrogen chloride here is carried out in the presence of a catalyst, and the catalyst includes any one of anhydrous ferric chloride, anhydrous aluminum trichloride, anhydrous zinc chloride, anhydrous ferrous dichloride, anhydrous rhodium chloride, and anhydrous chromium trichloride.

[0019] Furthermore, in step (1), the amino silane coupling agent is at least two of the above-mentioned coupling agents. For example, the coupling agent includes component A and component B; component A is selected from at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylethyldimethoxysilane, and γ-aminopropylethyldiethoxysilane, and component B is selected from at least one of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-divinyltriaminepropylmethyldimethoxysilane, 3-divinyltriaminepropyltrimethoxysilane, and 3-divinyltriaminepropyltriethoxysilane; wherein, the molar ratio of component A to component B is (0 - 1):(1 - 2), the molar amount of component B is greater than that of component A, and the amount of component A is not zero.

[0020] The combination of different coupling agents can better exert the steric effect, improve the stability of the catalyst, and enable it to be used for a long time. Further, the amino-silane coupling agent is at least three of the above-mentioned coupling agents. For example, the coupling agent comprises component a, component b, and component c; component a is selected from at least one of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylethyldimethoxysilane, γ-aminopropylethyldiethoxysilane, component b is selected from at least one of N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, and component c is selected from at least one of 3-divinyltriaminopropylmethyldimethoxysilane, 3-divinyltriaminopropyltrimethoxysilane, 3-divinyltriaminopropyltriethoxysilane; the molar ratio of component a, component b, and component c is (0-1):(1-2):(2-4), and the molar amounts of the three components are such that component c > component b > component a, and the amount of component a is not 0. As the amino chain length and the number of amino groups in component a, component b, and component c increase, their amounts gradually increase, resulting in a gradient distribution of amino groups on the surface of the carrier. The composite modification with amino chains of different lengths is more conducive to improving the dispersion performance of trivalent metal ions. On the basis of using a coupling agent with a long amino carbon chain as the main body, a small amount of a coupling agent with a short amino carbon chain is introduced into the composite coupling agent, which can, while giving full play to the excellent complexing effect of the long-chain amino group, also solve the steric effect caused by the longer amino carbon chain and improve the complexing ability for trivalent metal ions.

[0021] Further, the specific process of step (1) is as follows: Place the γ-alumina powder in a solvent, then add the amino-silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain the modified γ-alumina powder; the dispersion is carried out by an ultrasonic process with an ultrasonic power of 100-200 W. The temperature of the heating reaction is 45-60°C, and the reaction time is 1-3 h. Through the ultrasonic dispersion process, the coupling agent can be promoted to enter the micropores of the alumina powder for full modification. The heating process, on the one hand, improves the modification rate, and on the other hand, improves the mobility of the coupling agent molecular chain and promotes the uniformity of the surface modification of alumina.

[0022] Further, the trivalent metal salt in step (2) is at least one of an aluminum salt, a chromium salt, an iron salt, or a rhodium salt. Compared with divalent metal ions such as copper, zinc, magnesium, and palladium, the trivalent metal salt is more stable; more importantly, the trivalent metal salt is more likely to undergo a complexation reaction with polyamines, improving the stability of the catalyst.

[0023] Further, the impregnation process in step (2) is the equal-volume impregnation process. Based on the total mass of the catalyst, the loading amount of the trivalent metal salt is 15-30 wt%. In particular, the trivalent metal salt is impregnated in the form of an aqueous solution.

[0024] Further, in step (3), under a heating state, nitrogen is passed through for activation.

[0025] Further, the heating temperature in step (3) is 100-200 °C.

[0026] Further, in step (4), the reaction temperature is 70-200 °C and the reaction pressure is 0-1 MPa.

[0027] In some cases, the dehydrochlorination reaction temperature of 1,1,1,3-tetrachloropropane can be between 80-180 °C, or between 90-170 °C, or between 100-160 °C, or between 110-150 °C, or between 120-140 °C. In some cases, the dehydrochlorination reaction pressure of 1,1,1,3-tetrachloropropane can be between 0-0.8 MPa, or between 0.08-0.7 MPa, or between 0.09-0.6 MPa, or between 0.1-0.6 MPa, or between 0.1-0.3 MPa, or between 0.15-0.2 MPa.

[0028] Considering the reaction efficiency and cost factors, the reaction temperature is preferably between 120-140 °C and the reaction pressure is between 0.1-0.6 MPa. An appropriate pressure can make 1,1,1,3-tetrachloropropane in a liquid phase to contact with the catalyst for dehydrochlorination reaction, and can also improve the reaction activity and accelerate the reaction rate. In particular, the reaction pressure can be atmospheric pressure, and the atmospheric pressure reaction can reduce the requirements for equipment and lower the production cost.

[0029] Further, the processes of steps (3) and (4) are carried out in a tower reactor, a stirred tank reactor or a tubular reactor.

[0030] Further, in step (4), a tail gas absorption device is also included.

[0031] Further, the tail gas absorption device in step (4) is an absorption device with an aqueous solution as an alkaline solution. By adding a tail gas absorption device, the emission of tail gases such as hydrogen chloride can be prevented, and environmental pollution can be avoided.

[0032] The weak acidity on the catalyst surface is beneficial to the improvement of catalytic activity. However, during the catalytic dehydrochlorination process, conventional catalysts are prone to chlorine absorption, generating strong acidic sites. These strong acidic sites can easily cause dimerization of olefin products, not only reducing selectivity but also increasing coking and carbon deposition on the catalyst surface, leading to a decrease in catalytic performance. The trivalent metal ions complexed with an amino-silane coupling agent avoid this problem. This catalyst attaches the active components to the solid matrix, not only reducing phenomena such as chlorine absorption and coking, but also enabling the dehydrochlorination reaction to occur when 1,1,1,3-tetrachloropropane contacts the solid matrix. On the basis of high conversion rate and selectivity, it further improves the catalyst stability, avoids the occurrence of side reactions, and is conducive to the separation, recycling, and reuse of the catalyst.

[0033] Beneficial effects: On the one hand, the siloxane bonds in the coupling agent can undergo hydrolysis reactions with the hydroxyl groups on the surface of γ-aluminum oxide powder, overcoming the van der Waals forces and electrostatic attractions and other physical forces existing between γ-aluminum oxide particles, and improving the dispersion performance of the powder. On the other hand, due to the presence of various amino groups in the coupling agent, it can complex with trivalent metal salts, improving the stability of the trivalent metal salts. Compared with divalent metal ions such as copper, zinc, magnesium, and palladium, trivalent metal salts are more stable; more importantly, trivalent metal salts are more likely to undergo complexation reactions with polyamines, improving the stability of the catalyst. This catalyst attaches the active components to the solid matrix, not only reducing phenomena such as chlorine absorption and coking, but also enabling the dehydrochlorination reaction to occur when 1,1,1,3-tetrachloropropane contacts the solid matrix. On the basis of high conversion rate and selectivity, it further improves the catalyst stability, avoids the occurrence of side reactions, and is conducive to the separation, recycling, and reuse of the catalyst. Specific implementation methods

[0034] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0035] Example 1

[0036] A production process for the dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0037] (1) Place γ-aluminum oxide powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.4, then add an amino-silane coupling agent, disperse evenly, heat and react, filter, wash, and dry to obtain modified γ-aluminum oxide powder; the mass ratio of γ-aluminum oxide powder to the amino-silane coupling agent is 1:0.13; the specific surface area of the γ-aluminum oxide powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; The amino group-containing silane coupling agent is 3-divinyltriaminopropylmethyldimethoxysilane; The dispersion is carried out by an ultrasonic process with an ultrasonic power of 170 W; The temperature of the heating reaction is 50 °C and the reaction time is 2.3 h;

[0038] (2) A modified γ-alumina powder loaded with a trivalent metal salt is prepared by an equal-volume impregnation process and dried to obtain a catalyst; The trivalent metal salt is ferric chloride and is impregnated by an aqueous ferric chloride solution impregnation method to make the loading amount of the trivalent iron salt 21.5 wt%.

[0039] (3) 15 g of the catalyst is filled into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens are installed at both ends of the reaction tube to block the catalyst inside the tube; Under a heated state, nitrogen is passed through for activation; The heating temperature is 180 °C;

[0040] (4) Under the conditions of a reaction temperature of 139 °C and a reaction pressure of 0.57 MPa, 1,1,1,3-tetrachloropropane is introduced for dehydrochlorination reaction with a flow rate of 0.35 mL / min, and the tail gas generated by the reaction is absorbed by an aqueous solution; After 3 h, the sample leaving the tube is collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane is tested to be 70.1% and the selectivity of 1,1,3-trichloropropene is 96.7%.

[0041] Example 2

[0042] A production process for dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0043] (1) The γ-alumina powder is placed in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.2, and then an amino group-containing silane coupling agent is added, dispersed evenly, heated for reaction, filtered, washed, and dried to obtain a modified γ-alumina powder; The mass ratio of the γ-alumina powder to the amino group-containing silane coupling agent is 1:0.12; The specific surface area of the γ-alumina powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; The amino group-containing silane coupling agent is 3-divinyltriaminopropylmethyldimethoxysilane; The dispersion is carried out by an ultrasonic process with an ultrasonic power of 160 W; The temperature of the heating reaction is 52 °C and the reaction time is 2.1 h;

[0044] (2) A modified γ-alumina powder loaded with a trivalent metal salt is prepared by an equal-volume impregnation process and dried to obtain a catalyst; The trivalent metal salt is chromium chloride and is impregnated by an aqueous chromium chloride solution impregnation method to make the loading amount of the trivalent chromium salt 21.2 wt%.

[0045] (3) Load 15 g of the catalyst into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens are installed at both ends of the reaction tube to seal the catalyst inside the tube. Under a heated state, nitrogen is passed through for activation. The heating temperature is 170 °C;

[0046] (4) Under the conditions of a reaction temperature of 135 °C and a reaction pressure of 0.55 MPa, 1,1,1,3 - tetrachloropropane is introduced for dehydrochlorination reaction at a flow rate of 0.35 mL / min, and the tail gas generated by the reaction is absorbed using an aqueous solution. After 3 h, the sample leaving the tube is collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3 - tetrachloropropane is tested to be 65.9%, and the selectivity of 1,1,3 - trichloropropene is 97.0%.

[0047] Example 3

[0048] A production process for dehydrochlorination of 1,1,1,3 - tetrachloropropane:

[0049] (1) Place γ - alumina powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.4, then add an amino - silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain modified γ - alumina powder. The mass ratio of γ - alumina powder to the amino - silane coupling agent is 1:0.18. The specific surface area of the γ - alumina powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g. The amino - silane coupling agent is 3 - diethylenetriaminepropyltrimethoxysilane. The dispersion uses an ultrasonic process with an ultrasonic power of 170 W. The temperature of the heating reaction is 56 °C, and the reaction time is 2.5 h;

[0050] (2) Prepare modified γ - alumina powder loaded with trivalent metal salt by an equal - volume impregnation process, and obtain the catalyst after drying. The trivalent metal salt is chromium chloride, and it is impregnated by the chromium chloride aqueous solution impregnation method to make the loading amount of trivalent chromium salt 22.3 wt%.

[0051] (3) Load 15 g of the catalyst into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens are installed at both ends of the reaction tube to seal the catalyst inside the tube. Under a heated state, nitrogen is passed through for activation. The heating temperature is 195 °C;

[0052] (4) Under the conditions of a reaction temperature of 145 °C and a reaction pressure of 0.64 MPa, 1,1,1,3 - tetrachloropropane is introduced for dehydrochlorination reaction at a flow rate of 0.35 mL / min, and the tail gas generated by the reaction is absorbed using an aqueous solution. After 3 h, the sample leaving the tube is collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3 - tetrachloropropane is tested to be 71.1%, and the selectivity of 1,1,3 - trichloropropene is 98.0%.

[0053] Example 4

[0054] A production process for dehydrochlorination of 1,1,1,3 - tetrachloropropane:

[0055] (1) Place γ - alumina powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.3, then add an amino - silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain modified γ - alumina powder; the mass ratio of γ - alumina powder to the amino - silane coupling agent is 1:0.15; the specific surface area of the γ - alumina powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; the amino - silane coupling agent is a mixture of 3 - diethylenetriaminepropylmethyldimethoxysilane and 3 - diethylenetriaminepropyltrimethoxysilane with a molar ratio of 1:1; the dispersion uses an ultrasonic process with an ultrasonic power of 200 W; the temperature of the heating reaction is 60 °C, and the reaction time is 1.9 h;

[0056] (2) Prepare modified γ - alumina powder loaded with trivalent metal salts by the equal - volume impregnation process, and obtain a catalyst after drying; the trivalent metal salt is chromium chloride, and it is impregnated by the chromium chloride aqueous solution impregnation method to make the loading amount of trivalent chromium salt 22.8 wt%.

[0057] (3) Load 15 g of the catalyst into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens are installed at both ends of the reaction tube to block the catalyst inside the tube; under a heating state, nitrogen is passed for activation; the heating temperature is 180 °C;

[0058] (4) Under the conditions of a reaction temperature of 139 °C and a reaction pressure of 0.58 MPa, pass 1,1,1,3 - tetrachloropropane for dehydrochlorination reaction with a flow rate of 0.35 mL / min, and use an aqueous solution to absorb the tail gas generated by the reaction; after 3 h, collect the sample leaving the tube and conduct chromatographic analysis. The conversion rate of 1,1,1,3 - tetrachloropropane is 72.8%, and the selectivity of 1,1,3 - trichloropropene is 97.3%.

[0059] Example 5

[0060] A production process for dehydrochlorination of 1,1,1,3 - tetrachloropropane:

[0061] (1) Place γ-aluminum oxide powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.1, then add an amino-silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain modified γ-aluminum oxide powder; the mass ratio of γ-aluminum oxide powder to the amino-silane coupling agent is 1:0.13; the specific surface area of the γ-aluminum oxide powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; the amino-silane coupling agent is 3-divinyltriaminopropylmethyldimethoxysilane; the dispersion adopts an ultrasonic process with an ultrasonic power of 170 W; the temperature of the heating reaction is 55 °C, and the reaction time is 2.2 h;

[0062] (2) Prepare modified γ-aluminum oxide powder loaded with trivalent metal salt by the equal-volume impregnation process, and obtain the catalyst after drying; the trivalent metal salt is ferric chloride, and it is impregnated by the ferric chloride aqueous solution impregnation method to make the loading amount of the trivalent iron salt 21.6 wt%.

[0063] (3) Under the conditions of 115 ± 5 °C and passing nitrogen, activate the catalyst prepared in step (2);

[0064] (4) Add the activated catalyst and 1,1,1,3-tetrachloropropane to a stirred tank reactor, and the mass ratio of the catalyst to 1,1,1,3-tetrachloropropane is 3.6:100; at a reaction temperature of 137 °C and a reaction pressure of 0.56 MPa, react for 2.7 h, and use an aqueous solution to absorb the tail gas generated by the reaction; after the reaction is completed, separate the catalyst and the product, and conduct chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane is measured to be 74.7%, and the selectivity of 1,1,3-trichloropropene is 96.8%.

[0065] Example 6

[0066] A process for the production of 1,1,1,3-tetrachloropropane by dehydrochlorination:

[0067] (1) Place γ-aluminum oxide powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.4, then add an amino-silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain modified γ-aluminum oxide powder; the mass ratio of γ-aluminum oxide powder to the amino-silane coupling agent is 1:0.17; the specific surface area of the γ-aluminum oxide powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; the amino-silane coupling agent is 3-divinyltriaminopropyltrimethoxysilane; the dispersion adopts an ultrasonic process with an ultrasonic power of 190 W; the temperature of the heating reaction is 58 °C, and the reaction time is 1.9 h;

[0068] (2) The modified γ-alumina powder loaded with trivalent metal salt was prepared by the equal-volume impregnation process, and the catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and it was impregnated by the ferric chloride aqueous solution impregnation method, so that the loading amount of ferric salt was 21.9 wt%.

[0069] (3) Under the conditions of 110 ± 5 °C and nitrogen passing, the catalyst prepared in step (2) was activated.

[0070] (4) The activated catalyst and 1,1,1,3-tetrachloropropane were added into a stirred tank reactor, and the mass ratio of the catalyst to 1,1,1,3-tetrachloropropane was 3.3:100; at a reaction temperature of 140 °C and a reaction pressure of 0.54 MPa, the reaction was carried out for 2.6 h, and the tail gas generated by the reaction was absorbed by an aqueous solution; after the reaction was completed, the catalyst and the product were separated, and chromatographic analysis was carried out. The conversion rate of 1,1,1,3-tetrachloropropane was tested to be 75.8%, and the selectivity of 1,1,3-trichloropropene was 96.5%.

[0071] Example 7

[0072] A production process for dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0073] (1) The γ-alumina powder was placed in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.5, and then an amino-silane coupling agent was added, dispersed evenly, heated and reacted, filtered, washed, and dried to obtain the modified γ-alumina powder; the mass ratio of the γ-alumina powder to the amino-silane coupling agent was 1:0.16; the specific surface area of the γ-alumina powder was 271 m 2 / g, the average pore diameter was 8.3 nm, and the pore volume was 0.69 cm 3 / g; the amino-silane coupling agent was 3-divinyltriaminopropyltrimethoxysilane; the dispersion was carried out by an ultrasonic process, and the ultrasonic power was 185 W; the temperature of the heating reaction was 57 °C, and the reaction time was 3 h.

[0074] (2) The modified γ-alumina powder loaded with trivalent metal salt was prepared by the equal-volume impregnation process, and the catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and it was impregnated by the ferric chloride aqueous solution impregnation method, so that the loading amount of ferric salt was 22.0 wt%.

[0075] (3) 15 g of the catalyst was loaded into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens were installed at both ends of the reaction tube to block the catalyst in the tube; under the heating state, nitrogen was passed for activation; the heating temperature was 188 °C.

[0076] (4)Under the conditions of a reaction temperature of 143 °C and a reaction pressure of 0.62 MPa, 1,1,1,3-tetrachloropropane was introduced for dehydrochlorination reaction with a flow rate of 0.35 mL / min, and the tail gas generated by the reaction was absorbed by an aqueous solution; after 3 h, the sample leaving the tube was collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane was tested to be 68.1%, and the selectivity of 1,1,3-trichloropropene was 96.2%.

[0077] Example 8

[0078] A production process for dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0079] (1)γ-alumina powder was placed in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.5, and then an amino-silane coupling agent was added, dispersed evenly, heated for reaction, filtered, washed, and dried to obtain modified γ-alumina powder; the mass ratio of γ-alumina powder to the amino-silane coupling agent was 1:0.16; the specific surface area of the γ-alumina powder was 271 m 2 / g, the average pore diameter was 8.3 nm, and the pore volume was 0.69 cm 3 / g; the amino-silane coupling agent was a mixture of 3-divinyltriaminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane with a molar ratio of 0.5:1.5; the dispersion was carried out by an ultrasonic process with an ultrasonic power of 185 W; the temperature of the heating reaction was 57 °C, and the reaction time was 3 h;

[0080] (2)The modified γ-alumina powder loaded with trivalent metal salts was prepared by an equal-volume impregnation process and dried to obtain a catalyst; the trivalent metal salt was ferric chloride, and it was impregnated by the ferric chloride aqueous solution impregnation method to make the loading amount of the trivalent iron salt 22.0 wt%.

[0081] (3)15 g of the catalyst was loaded into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens were installed at both ends of the reaction tube to block the catalyst inside the tube; under a heated state, nitrogen was passed through for activation; the heating temperature was 188 °C;

[0082] (4)Under the conditions of a reaction temperature of 143 °C and a reaction pressure of 0.62 MPa, 1,1,1,3-tetrachloropropane was introduced for dehydrochlorination reaction with a flow rate of 0.35 mL / min, and the tail gas generated by the reaction was absorbed by an aqueous solution; after 3 h, the sample leaving the tube was collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane was tested to be 69.6%, and the selectivity of 1,1,3-trichloropropene was 97.3%.

[0083] Example 9

[0084] A production process for dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0085] (1) Place the γ-aluminum oxide powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.5, then add an amino-silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain modified γ-aluminum oxide powder; the mass ratio of the γ-aluminum oxide powder to the amino-silane coupling agent is 1:0.16; the specific surface area of the γ-aluminum oxide powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; the amino-silane coupling agent is a mixture of 3-divinyltriaminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane with a molar ratio of 1.5:0.5; the dispersion is carried out by an ultrasonic process with an ultrasonic power of 185 W; the temperature of the heating reaction is 57 °C, and the reaction time is 3 h;

[0086] (2) Prepare the modified γ-aluminum oxide powder loaded with trivalent metal salt by an equal-volume impregnation process, and obtain the catalyst after drying; the trivalent metal salt is ferric chloride, and it is impregnated by the ferric chloride aqueous solution impregnation method so that the loading amount of the trivalent iron salt is 22.0 wt%.

[0087] (3) Load 15 g of the catalyst into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens are installed at both ends of the reaction tube to block the catalyst inside the tube; under a heating state, nitrogen is passed for activation; the heating temperature is 188 °C;

[0088] (4) Under the conditions of a reaction temperature of 143 °C and a reaction pressure of 0.62 MPa, introduce 1,1,1,3-tetrachloropropane for dehydrochlorination reaction with a flow rate of 0.35 mL / min, and use an aqueous solution to absorb the tail gas generated by the reaction; after 3 h, collect the sample leaving the tube and conduct chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane is tested to be 71.5%, and the selectivity of 1,1,3-trichloropropene is 97.8%.

[0089] Example 10

[0090] A production process for dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0091] (1) Place the γ-aluminum oxide powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.5, then add an amino-silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain modified γ-aluminum oxide powder; the mass ratio of the γ-aluminum oxide powder to the amino-silane coupling agent is 1:0.16; the specific surface area of the γ-aluminum oxide powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; The amino-silane coupling agent is a mixture of 3-divinyltriaminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane with a molar ratio of 3:0.5:1.5; The dispersion is carried out by an ultrasonic process with an ultrasonic power of 185 W; The temperature of the heating reaction is 57 °C and the reaction time is 3 h;

[0092] (2) The modified γ-alumina powder loaded with trivalent metal salt is prepared by an equal-volume impregnation process, and the catalyst is obtained after drying; The trivalent metal salt is ferric chloride, and it is impregnated by the ferric chloride aqueous solution impregnation method to make the loading amount of the trivalent iron salt 22.0 wt%.

[0093] (3) 15 g of the catalyst is loaded into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens are installed at both ends of the reaction tube to block the catalyst inside the tube; Under a heating state, nitrogen is passed through for activation; The heating temperature is 188 °C;

[0094] (4) Under the conditions of a reaction temperature of 143 °C and a reaction pressure of 0.62 MPa, 1,1,1,3-tetrachloropropane is introduced for dehydrochlorination reaction with a flow rate of 0.35 mL / min, and the tail gas generated by the reaction is absorbed by an aqueous solution; After 3 h, the sample leaving the tube is collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane is tested to be 73.7%, and the selectivity of 1,1,3-trichloropropene is 98.5%.

[0095] Example 11

[0096] A production process for dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0097] (1) The γ-alumina powder is placed in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.5, and then an amino-silane coupling agent is added, dispersed evenly, heated for reaction, filtered, washed, and dried to obtain modified γ-alumina powder; The mass ratio of the γ-alumina powder to the amino-silane coupling agent is 1:0.16; The specific surface area of the γ-alumina powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; The amino-silane coupling agent is a mixture of 3-divinyltriaminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane with a molar ratio of 3:1.5:0.5; The dispersion is carried out by an ultrasonic process with an ultrasonic power of 185 W; The temperature of the heating reaction is 57 °C and the reaction time is 3 h;

[0098] (2) The modified γ-alumina powder loaded with trivalent metal salt was prepared by the equal-volume impregnation process, and the catalyst was obtained after drying; the trivalent metal salt was ferric chloride, and it was impregnated by the ferric chloride aqueous solution impregnation method so that the loading amount of ferric salt was 22.0 wt%.

[0099] (3) 15 g of the catalyst was loaded into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens were installed at both ends of the reaction tube to block the catalyst inside the tube; under a heated state, nitrogen was passed through for activation; the heating temperature was 188 °C;

[0100] (4) Under the conditions of a reaction temperature of 143 °C and a reaction pressure of 0.62 MPa, 1,1,1,3-tetrachloropropane was introduced for dehydrochlorination reaction, with a flow rate of 0.35 mL / min, and the tail gas generated by the reaction was absorbed by an aqueous solution; after 3 h, the sample leaving the tube was collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane was tested to be 75.9%, and the selectivity of 1,1,3-trichloropropene was 98.9%.

[0101] Comparative Example 1

[0102] (1) The γ-alumina powder loaded with trivalent metal salt was prepared by the equal-volume impregnation process, and the catalyst was obtained after drying; the specific surface area of the γ-alumina powder was 271 m 2 / g, the average pore diameter was 8.3 nm, and the pore volume was 0.69 cm 3 / g; the trivalent metal salt was ferric chloride, and it was impregnated by the ferric chloride aqueous solution impregnation method so that the loading amount of ferric salt was 22.0 wt%.

[0103] (2) 15 g of the catalyst was loaded into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens were installed at both ends of the reaction tube to block the catalyst inside the tube; under a heated state, nitrogen was passed through for activation; the heating temperature was 188 °C;

[0104] (3) Under the conditions of a reaction temperature of 143 °C and a reaction pressure of 0.62 MPa, 1,1,1,3-tetrachloropropane was introduced for dehydrochlorination reaction, with a flow rate of 0.35 mL / min, and the tail gas generated by the reaction was absorbed by an aqueous solution; after 3 h, the sample leaving the tube was collected and subjected to chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane was tested to be 55.6%, and the selectivity of 1,1,3-trichloropropene was 90.7%.

[0105] Comparative Example 2

[0106] A production process for dehydrochlorination of 1,1,1,3-tetrachloropropane:

[0107] (1) Place γ-aluminum oxide powder in a mixed solvent with a volume ratio of deionized water to ethanol of 1:1.5, then add an amino-silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry to obtain modified γ-aluminum oxide powder; the mass ratio of γ-aluminum oxide powder to the amino-silane coupling agent is 1:0.4; the specific surface area of the γ-aluminum oxide powder is 271 m 2 / g, the average pore diameter is 8.3 nm, and the pore volume is 0.69 cm 3 / g; the amino-silane coupling agent is a mixture of 3-divinyltriaminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane with a molar ratio of 3:1.5:0.5; the dispersion adopts an ultrasonic process with an ultrasonic power of 185 W; the temperature of the heating reaction is 57 °C, and the reaction time is 3 h;

[0108] (2) Prepare modified γ-aluminum oxide powder loaded with trivalent metal salts by an equal-volume impregnation process, and obtain a catalyst after drying; the trivalent metal salt is ferric chloride, and it is impregnated by the ferric chloride aqueous solution impregnation method to make the loading amount of the trivalent iron salt 22.0 wt%.

[0109] (3) Load 15 g of the catalyst into a reaction tube with a length of 25 cm and a diameter of 1.2 cm. Screens are installed at both ends of the reaction tube to block the catalyst inside the tube; under a heating state, nitrogen is passed through for activation; the heating temperature is 188 °C;

[0110] (4) Under the conditions of a reaction temperature of 143 °C and a reaction pressure of 0.62 MPa, introduce 1,1,1,3-tetrachloropropane for dehydrochlorination reaction with a flow rate of 0.35 mL / min, and use an aqueous solution to absorb the tail gas generated by the reaction; after 3 h, collect the sample leaving the tube and conduct chromatographic analysis. The conversion rate of 1,1,1,3-tetrachloropropane is tested to be 62.7%, and the selectivity of 1,1,3-trichloropropene is 93.6%.

[0111] The weak acidity on the catalyst surface is beneficial to the improvement of catalytic activity. However, during the catalytic dehydrochlorination process, conventional catalysts are prone to chlorine absorption, generating strong acidic sites, and the strong acidic sites are likely to cause dimerization of olefin products, which not only leads to a decrease in selectivity but also increases coking and carbon deposition on the catalyst surface, resulting in a decrease in catalytic performance. The trivalent metal ions complexed by the amino-silane coupling agent avoid this problem. This catalyst attaches the active components to the solid matrix, not only reducing phenomena such as chlorine absorption and coking, but also the dehydrochlorination reaction occurs when 1,1,1,3-tetrachloropropane contacts the solid matrix. On the basis of high conversion rate and selectivity, the catalyst stability is further improved, side reactions are avoided, and it is beneficial to the separation and recycling of the catalyst.

[0112] As can be seen from Examples 7-11, the combined use of different coupling agents can better exert the steric effect, improve the stability of the catalyst, and enable it to be used for a long time. For multi-component coupling systems, as the amino chain length and the number of amino groups in the components increase, the dosage gradually increases, resulting in a gradient distribution of amino groups on the carrier surface. The composite modification with amino chains of different lengths is more conducive to improving the dispersion performance of trivalent metal ions. Based on the coupling agent with a long amino carbon chain as the main body, a small amount of coupling agent with a short amino carbon chain is introduced into the composite coupling agent, which can, on the basis of exerting the excellent complexing effect of the long-chain amino group, solve the steric hindrance effect caused by the long-chain amino carbon chain and improve the complexing ability for trivalent metal ions. Compared with Example 11, in Comparative Example 1, the γ-alumina powder was not modified with an amino silane coupling agent, resulting in a decrease in the catalytic activity of the catalyst. Compared with Example 11, in Comparative Example 2, too much coupling agent was used. Due to the branched structure of the coupling agent, when the dosage is too much, it will lead to a decrease in the carrier loading efficiency, which is not conducive to the loading of the pore structure, affects the dispersion of the active components, and results in a decrease in the selectivity of 1,1,3-trichloropropene.

[0113] 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, various modifications and changes can be made to the present invention. 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 production process for dehydrochlorination of 1,1,1,3 - tetrachloropropane, characterized in that, It includes the following steps: (1) Modify γ-alumina powder with an amino-silane coupling agent to prepare modified γ-alumina powder; the mass ratio of γ-alumina powder to the amino-silane coupling agent is 1:(0.01 - 0.2); the amino-silane coupling agent is at least one of γ-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-divinyltriaminepropylmethyldimethoxysilane, and 3-divinyltriaminepropyltrimethoxysilane; (2) Prepare a catalyst by impregnation process with the modified γ-alumina powder loaded with trivalent metal salt; the trivalent metal salt is at least one of chromium salt or iron salt; (3) Activate the catalyst; (4) Adjust the reaction temperature and pressure, introduce 1,1,1,3-tetrachloropropane for dehydrochlorination reaction to obtain 1,1,3-trichloropropene; The preparation process of the modified γ-alumina powder in step (1) is: place the γ-alumina powder in a solvent, then add the amino-silane coupling agent, disperse evenly, heat for reaction, filter, wash, and dry; the dispersion uses ultrasonic process; the temperature of the heating reaction is 45 - 60 °C, and the reaction time is 1 - 3 h.

2. The 1,1,1,3-tetrachloropropane dehydrochlorination production process according to claim 1, characterized in that, Use the obtained 1,1,3-trichloropropene as raw material, and chlorinate it with chlorine to prepare 1,1,1,2,3-pentachloropropane; use 1,1,1,2,3-pentachloropropane as raw material to dehydrochlorinate to prepare 1,1,2,3-tetrachloropropene.

3. The 1,1,1,3-tetrachloropropane dehydrochlorination production process according to claim 1, characterized in that, The impregnation process in step (2) is the equal-volume impregnation process.

4. A process for the production of 1,1,1,3 - tetrachloropropane by dehydrochlorination, as described in claim 1, characterized in that, In step (3), under heating condition, introduce nitrogen for activation.

5. A process for the production of 1,1,1,3-tetrachloropropane by dehydrochlorination, as described in claim 4, characterized in that, The heating temperature in step (3) is 100 - 200 °C.

6. The production process for the dehydrochlorination of 1,1,1,3-tetrachloropropane as described in claim 1, characterized in that, The reaction temperature in step (4) is 70 - 200 °C, and the reaction pressure is 0 - 1 MPa.

7. A process for the production of 1,1,1,3-tetrachloropropane by dehydrochlorination, as described in claim 1, characterized in that, The processes of step (3) and step (4) are carried out in a tower reactor, a stirred tank reactor or a tubular reactor.

8. A process for the production of 1,1,1,3-tetrachloropropane by dehydrochlorination, as claimed in claim 1, wherein, A tail gas absorption device is also included in step (4).