Preparation method of tert-dodecyl mercaptan

Abstract

The invention belongs to the field of organic matter synthesis, and particularly discloses a preparation method of tert-dodecyl mercaptan, which is characterized in that hydrogen sulfide and dodecene are used as raw materials, and an addition reaction is performed under the catalytic action of a solid acid catalyst by adopting a liquid-solid heterogeneous process and a fixed bed reactor to obtain the tert-dodecyl mercaptan. The continuous liquid-solid reaction is realized, the diffusion time of hydrogen sulfide to a liquid phase main body is shortened, the heat capacity and the heat transfer coefficient of a reaction system are improved, the catalytic efficiency of the catalyst and the temperature controllability of the reaction process are improved, and the reactor design is simplified. Under proper operation conditions, the conversion per pass of dodecene is greater than or equal to 85%, the selectivity is close to 100%, the technological process is simple, few three wastes are generated, treatment is easy, and the method is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the field of organic synthesis, in particular to a method for preparing tert-dodecyl mercaptan. Background Art

[0002] Tert-dodecyl mercaptan is mainly used as a polymerization degree (molecular weight) regulator in the synthesis process of polymer materials such as styrene-butadiene rubber and ABS resin, which reduces the branching degree of the polymer chain and makes the relative molecular mass distribution uniform. With the rapid development of the field of polymer material synthesis, the apparent consumption of SBR and ABS resins has been increasing year by year. According to incomplete statistics, the new production capacity of ABS resin in my country is expected to reach 5784.5kt from 2022 to 2026. With the continuous growth of demand for downstream products, the demand for tert-dodecyl mercaptan will further increase in the future, and even double.

[0003] Although industrial production facilities have been built in China before (Suileng Chemical Plant in Heilongjiang Province and Weishan Chemical Plant in Shandong Province), they have been discontinued due to reasons such as raw materials, production technology, and environmental protection. For many years, the tert-dodecyl mercaptan market has been monopolized by foreign manufacturers (Arkema in France, Isu in South Korea, and Phillips in the United States, etc.). Many domestic enterprises and research institutions have also conducted research on the synthesis of tert-dodecyl mercaptan, but most of them focus on the gas-liquid-solid three-phase trickle bed reaction process and the liquid phase homogeneous intermittent synthesis process. Due to the strong exothermic effect of the catalytic addition reaction of dodecene and hydrogen sulfide, the structure of the trickle bed must adopt a tubular design and layout, resulting in many problems such as complex design and difficulty in uniform distribution of liquid distribution elements, and great difficulty in engineering amplification. This is also one of the reasons why there is no tert-dodecyl mercaptan production facility in China so far. Developing a tert-dodecyl mercaptan production process suitable for industrial amplification is necessary for my country to get rid of its dependence on imports. Therefore, it is intended to develop a continuous production process for tert-dodecyl mercaptan with simple process, easy industrial amplification, high conversion rate and high selectivity. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing tert-dodecyl mercaptan.

[0005] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0006] A method for preparing tert-dodecyl mercaptan comprises the following steps:

[0007] S1. Dissolving raw materials: mixing liquid dodecene and gaseous hydrogen sulfide at a molar ratio of 1:1-4 at a temperature of 0-50°C and a pressure of 0.5-5.0 MPa to completely dissolve the gaseous hydrogen sulfide to obtain a reaction mixed solution;

[0008] S2, reaction catalysis: the obtained reaction mixture is pumped out by a metering pump and preheated to 50-100° C. and sent into a fixed bed reactor to react under the catalytic action of a catalyst at a reaction pressure of 0.5-3.0 MPa to obtain tert-dodecyl mercaptan;

[0009] S3, product desorption: decompressing the obtained tert-dodecyl mercaptan to release unreacted hydrogen sulfide to obtain a crude tert-dodecyl mercaptan product;

[0010] S4. Product purification: The obtained crude tert-dodecyl mercaptan product is subjected to vacuum distillation, and the fractions in the distillation range of 95 to 130° C. are collected under an absolute pressure of 2 to 5 kPa to obtain the tert-dodecyl mercaptan product.

[0011] Preferably, in step S1, the raw material is dissolved at a temperature of 25° C. and a pressure of 1.3 MPa.

[0012] Preferably, in step S2, the reaction temperature is 60-90°C.

[0013] Preferably, in step S2, the catalyst is one of WLC-6 ion exchange resin, WLC-9 ion exchange resin, LXC-001 ion exchange resin, LXC-105 ion exchange resin, Amberlyst15 ion exchange resin, Amberlyst35 ion exchange resin, Amberlyst36 ion exchange resin, HND-31 solid acid catalyst and HND-33 solid acid catalyst.

[0014] Preferably, in step S3, the pressure is reduced to 0.03 MPa.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention is a continuous liquid-solid reaction, and the single-pass conversion rate of dodecene raw material is as high as 85% and the selectivity can reach 100%.

[0017] 2. The present invention shortens the diffusion process of hydrogen sulfide into the liquid phase, and forms a reactant solution before entering the reactor for reaction, which greatly improves the catalytic efficiency of the catalyst and the production intensity of the reactor.

[0018] 3. The liquid phase fixed bed process used in the present invention improves the catalytic efficiency of the catalyst compared to the traditional gas-liquid-solid three-phase trickle bed process. At the same time, due to the large heat capacity and high heat transfer coefficient of the liquid material, the temperature controllability of the reaction process is improved and the reactor design is simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1The present invention is a flow chart of the liquid phase preparation process of tert-dodecyl mercaptan. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0021] The dodecene used in the following examples is a raw material made from the high-boiling byproduct of the nonene device of Daqing Zhonglan Petrochemical Co., Ltd., and is purified and refined to obtain a dodecene raw material containing 90% to 95% dodecene, 5% to 10% decadecene and tert-undecene, and less than 1.0% tridecene or more. Hydrogen sulfide gas is purchased from Shandong Zibo Dijia Special Gas Co., Ltd., with a purity greater than 99%. High-purity nitrogen is purchased from Daqing Xuelong Petrochemical Technology Development Co., Ltd., with a purity greater than 99%. Cationic ion exchange resin catalysts, including models WLC-9, WLC-6, LXC-001, LXC-105, Amberlyst15, Amberlyst35 and Amberlyst36, are purchased from Hebei Wenlan Environmental Protection Technology Co., Ltd., Xi'an Lanxiao Technology Co., Ltd. and Jiangyin Nanda Synthetic Chemical Co., Ltd.; HND-31 and HND-33 solid acid catalysts are purchased from Jiangyin Nanda Synthetic Chemical Co., Ltd.

[0022] The dodecene conversion and tert-dodecyl mercaptan selectivity used in the following examples were measured by Agilent 7890B gas chromatography, capillary column: RTX-5, 50m×0.25mm×0.25μm; column temperature: initial temperature 50°C, maintained for 5min, and heated at 10°C / min to a final temperature of 280°C; FID detector detection, nitrogen as carrier gas, and feed amount of 0.5μL.

[0023] Example 1

[0024] Reference Figure 1 , the specific process for preparing tert-dodecyl mercaptan is as follows:

[0025] S1, raw material dissolution: control the temperature (25°C) and pressure (1.3Mpa) of the absorption and dissolution process, dissolve the gaseous hydrogen sulfide into the liquid dodecene at a molar ratio of 1:1 to obtain a mixed reaction solution; S2, reaction catalysis: the mixed solution obtained in S1 is pumped out through a metering pump and preheated to 60°C before entering a fixed bed reactor, and reacts under the catalytic action of the catalyst to obtain the target product tert-dodecyl mercaptan, the reaction pressure is 1.0Mpa, and the feed space velocity is 0.5h -1, react under the action of WLC-9 ion exchange resin to obtain the target product tert-dodecyl mercaptan; S3, product analysis: the reaction product obtained by S2 is placed in a flash tank and decompressed to 0.03MPa to release unreacted hydrogen sulfide to obtain a crude product of tert-dodecyl mercaptan; S4, the obtained crude product of tert-dodecyl mercaptan is subjected to vacuum distillation, and the fractions in the distillation range of 95 to 130°C are collected under an absolute pressure of 2 to 5kPa to obtain the tert-dodecyl mercaptan product, and the obtained tert-dodecyl mercaptan product is sampled for gas chromatography analysis.

[0026] Example 2

[0027] The difference from Example 1 is that the molar ratio of dodecene to hydrogen sulfide is 1:2.

[0028] Example 3

[0029] The difference from Example 1 is that the molar ratio of dodecene to hydrogen sulfide is 1:3.

[0030] Example 4

[0031] The difference from Example 1 is that the molar ratio of dodecene to hydrogen sulfide is 1:4.

[0032] The reaction results of Examples 1 to 4 are shown in Table 1.

[0033] Table 1 Reaction results of Examples 1 to 4

[0034] Example Dodecene: Hydrogen sulfide Dodecene conversion rate / % Thiol selectivity / % 1 1:1 58.67 100 2 1:2 64.51 100 3 1:3 72.10 100 4 1:4 76.31 100

[0035] Example 5

[0036] S1, raw material dissolution: control the temperature (25°C) and pressure (1.3Mpa) of the absorption and dissolution process, dissolve the gaseous hydrogen sulfide into the liquid dodecene at a molar ratio of 3:1 to obtain a mixed reaction solution; S2, reaction catalysis: the mixed solution obtained in S1 is pumped out through a metering pump and preheated to 70°C before entering a fixed bed reactor, and reacts under the catalytic action of the catalyst to obtain the target product tert-dodecyl mercaptan, the reaction pressure is 1.0Mpa, and the feed space velocity is 0.5h -1 , react under the action of WLC-9 ion exchange resin to obtain the target product tert-dodecyl mercaptan; S3, product analysis: the reaction product obtained by S2 is placed in a flash tank and decompressed to 0.03MPa to release unreacted hydrogen sulfide to obtain a crude product of tert-dodecyl mercaptan; S4, vacuum distill the obtained crude product of tert-dodecyl mercaptan, collect the fractions within a certain distillation range to obtain the tert-dodecyl mercaptan product, and take a sample of the obtained tert-dodecyl mercaptan product for gas chromatography analysis.

[0037] Example 6

[0038] The difference from Example 5 is that the preheating temperature is 80°C.

[0039] Example 7

[0040] The difference from Example 5 is that the preheating temperature is 90°C.

[0041] The reaction results of Examples 5 to 7 are shown in Table 2.

[0042] Table 2 Reaction results of Examples 5 to 7

[0043] Example Preheating temperature, °C Dodecene conversion rate / % Thiol selectivity / % 5 70 85.92 100 6 80 86.11 100 7 90 86.83 100

[0044] Example 8

[0045] S1, raw material dissolution: control the temperature (25°C) and pressure (1.3Mpa) of the absorption and dissolution process, dissolve gaseous hydrogen sulfide into liquid dodecene at a molar ratio of 3:1 to obtain a mixed reaction solution; S2, reaction catalysis: pump the mixed solution obtained in S1 through a metering pump and preheat it to 70°C before entering a fixed bed reactor, where it reacts under the catalytic action of the catalyst to obtain the target product, tert-dodecyl mercaptan, with a reaction pressure of 0.5Mpa and a feed space velocity of 0.5h -1 , react under the action of WLC-9 ion exchange resin to obtain the target product tert-dodecyl mercaptan; S3, product analysis: the reaction product obtained by S2 is placed in a flash tank and decompressed to 0.03MPa to release unreacted hydrogen sulfide to obtain a crude product of tert-dodecyl mercaptan; S4, vacuum distill the obtained crude product of tert-dodecyl mercaptan, collect the fractions within a certain distillation range to obtain the tert-dodecyl mercaptan product, and take a sample of the obtained tert-dodecyl mercaptan product for gas chromatography analysis.

[0046] Example 9

[0047] The difference from Example 8 is that the reaction pressure is 1.5 MPa.

[0048] Example 10

[0049] The difference from Example 8 is that the reaction pressure is 2.0 MPa.

[0050] Embodiment 11

[0051] The difference from Example 8 is that the reaction pressure is 3.0 MPa.

[0052] The reaction results of Example 8 to Example 11 are shown in Table 3.

[0053] Table 3 Reaction results of Examples 8 to 11

[0054] Example Reaction pressure, MPa Dodecene conversion rate / % Thiol selectivity / % 8 0.5 66.74 100 9 1.5 86.31 100 10 2.0 86.87 100 11 3.0 87.24 100

[0055] Example 12

[0056] S1, raw material dissolution: control the temperature (25°C) and pressure (1.3Mpa) of the absorption and dissolution process, dissolve the gaseous hydrogen sulfide into the liquid dodecene at a molar ratio of 3:1 to obtain a mixed reaction solution; S2, reaction catalysis: the mixed solution obtained in S1 is pumped out through a metering pump and preheated to 70°C before entering a fixed bed reactor, and reacts under the catalytic action of the catalyst to obtain the target product tert-dodecyl mercaptan, the reaction pressure is 1.0Mpa, and the feed space velocity is 0.1h -1 , react under the action of WLC-9 ion exchange resin to obtain the target product tert-dodecyl mercaptan; S3, product analysis: the reaction product obtained by S2 is placed in a flash tank and decompressed to 0.03MPa to release unreacted hydrogen sulfide to obtain a crude product of tert-dodecyl mercaptan; S4, vacuum distill the obtained crude product of tert-dodecyl mercaptan, collect the fractions within a certain distillation range to obtain the tert-dodecyl mercaptan product, and take a sample of the obtained tert-dodecyl mercaptan product for gas chromatography analysis.

[0057] Example 13

[0058] The difference from Example 12 is that the feed air velocity is 1.0h -1 .

[0059] Embodiment 14

[0060] The difference from Example 12 is that the feed air velocity is 1.5h -1 .

[0061] Embodiment 15

[0062] The difference from Example 12 is that the feed air velocity is 2.0h -1 .

[0063] The reaction results of Example 12 to Example 15 are shown in Table 4.

[0064] Table 4 Reaction results of Examples 12 to 15

[0065] Example <![CDATA[Operating airspeed, h -1 > Dodecene conversion rate / % Thiol selectivity / % 12 0.1 87.64 100 13 1.0 81.42 100 14 1.5 71.33 100 15 2.0 59.69 100

[0066] Comparative Example 1

[0067] The difference from Example 9 is that n-dodecene is used as the raw material instead of tetrapropylene.

[0068] The single-pass conversion rate of n-dodecene is 43.87%, and the total selectivity is close to 100%, of which the selectivity of n-dodecyl mercaptan is 84% ​​and the selectivity of isododecyl mercaptan is 16%.

[0069] Comparative Example 2

[0070] The difference from Example 9 is that trimerized isobutylene is used as the raw material instead of tetrapropylene.

[0071] The single-pass conversion of trimerized isobutylene was 90.87% and the selectivity was close to 73.4%.

[0072] Comparative Examples 3 to 10

[0073] The difference from Example 9 is that the catalysts are different. The catalysts used are WLC-6, LXC-001, LXC-105, Amberlyst15, Amberlyst35, Amberlyst36, HND-31 and HND-33 respectively. The reaction results are shown in Table 5.

[0074] Table 5 Reaction results of comparative examples 3 to 10

[0075] Comparative Example catalyst Dodecene conversion rate / % Thiol selectivity / % 3 WLC-6 79.31 100 4 LXC-001 80.22 100 5 LXC-105 45.11 100 6 Amberlyst15 76.52 100 7 Amberlyst35 68.21 100 8 Amberlyst36 72.58 100 9 HND-31 11.62 100 10 HND-33 17.31 100

[0076] Comparative Examples 11 to 16

[0077] The difference from Example 9 is that the preheating temperature is different. The preheating temperatures are 100°C, 110°C, 120°C, 130°C, 140°C and 150°C respectively. The reaction results are shown in Table 6.

[0078] Table 6 Reaction results of comparative examples 11 to 16

[0079] Comparative Example Reaction temperature, °C Dodecene conversion rate / % Thiol selectivity / % 11 100 86.95 100 12 110 87.31 99.0 13 120 87.64 96.41 14 130 88.82 89.78 15 140 88.43 85.46 16 150 89.13 81.37

[0080] In summary, the single-pass conversion rate of dodecene raw material in the present invention is as high as 85% and the selectivity can reach 100%.

[0081] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing tert-dodecyl mercaptan, characterized in that: The following steps are involved: S1. Dissolving raw materials: mixing liquid dodecene and gaseous hydrogen sulfide at a molar ratio of 1:1-4 at a temperature of 0-50°C and a pressure of 0.5-5.0 MPa to completely dissolve the gaseous hydrogen sulfide to obtain a reaction mixed solution; S2, reaction catalysis: the obtained reaction mixture is pumped out by a metering pump and preheated to 50-100° C. and sent into a fixed bed reactor to react under the catalytic action of a catalyst at a reaction pressure of 0.5-3.0 MPa to obtain tert-dodecyl mercaptan; S3, product desorption: decompressing the obtained tert-dodecyl mercaptan to release unreacted hydrogen sulfide to obtain a crude tert-dodecyl mercaptan product; S4. Product purification: The obtained crude tert-dodecyl mercaptan product is subjected to vacuum distillation, and the fractions in the distillation range of 95 to 130° C. are collected under an absolute pressure of 2 to 5 kPa to obtain the tert-dodecyl mercaptan product.

2. The method for preparing tert-dodecyl mercaptan according to claim 1, characterized in that: In the step S1, the raw material is dissolved at a temperature of 25° C. and a pressure of 1.3 MPa.

3. The method for preparing tert-dodecyl mercaptan according to claim 1, characterized in that: In the step S2, the reaction temperature is 60-90°C.

4. The method for preparing tert-dodecyl mercaptan according to claim 1, characterized in that: In step S2, the catalyst is one of WLC-6 ion exchange resin, WLC-9 ion exchange resin, LXC-001 ion exchange resin, LXC-105 ion exchange resin, Amberlyst15 ion exchange resin, Amberlyst35 ion exchange resin, Amberlyst36 ion exchange resin, HND-31 solid acid catalyst and HND-33 solid acid catalyst.

5. The method for preparing tert-dodecyl mercaptan according to claim 1, characterized in that: In the step S3, the pressure is reduced to 0.03 MPa.

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