Separation method of tert-dodecyl mercaptan and tetra-polypropylene

Abstract

The invention relates to the technical field of preparation and separation of tert-dodecyl mercaptan, in particular to a separation method of tert-dodecyl mercaptan and tetra-polypropylene, and aims to improve the yield while improving the separation purity and reduce the energy consumption and investment cost. The invention relates to a method for separating tert-dodecyl mercaptan and tetra-polypropylene, which comprises the following steps: adding an entrainer into a first mixed solution containing the tert-dodecyl mercaptan and the tetra-polypropylene to carry out azeotropic distillation, and respectively collecting a first fraction containing the tetra-polypropylene and the entrainer and a first distillation residue containing the tert-dodecyl mercaptan; wherein the entrainer is prepared from one or more of C6-C12 saturated monohydric fatty alcohol, and the entrainer is prepared from one or more of C6-C12 saturated monohydric fatty alcohol.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tert-dodecyl mercaptan preparation and separation, and particularly relates to a tert-dodecyl mercaptan and tetramerized propylene separation method. BACKGROUND

[0002] Tert-dodecyl mercaptan is a very important chemical intermediate as a polymer molecular weight regulator of synthetic resin and synthetic rubber and the like high molecular materials.

[0003] Tert-dodecyl mercaptan is produced by using tetramerized propylene and hydrogen sulfide as raw materials, and the conversion rate of the reaction is usually 80% to 90%, and the selectivity can reach more than 99%, so the reaction liquid is a mixture of tetramerized propylene and tert-dodecyl mercaptan. Tetramerized propylene is produced by propylene oligomerization process in industry, and the tetramerized propylene on the market is an olefin mixture of C10 to C14, because the solid phosphoric acid catalyst is used in the propylene oligomerization process, and the high-temperature strong acid catalysis is accompanied by chain breaking and recombination of propylene carbon chain, so the tetramerized propylene is not a single substance, but a mixture with complex structure containing different carbon numbers and numerous isomers. Usually, the C12 olefin content is 70% to 80%, and the rest is C10, C11, C13 and C14 olefins, and the boiling range is 162 DEG C to 237 DEG C. Similarly, the product tert-dodecyl mercaptan synthesized from the above tetramerized propylene is also a mixture, and the boiling range is 227 DEG C to 248 DEG C. Because the components with high boiling range in the tetramerized propylene and the components with low boiling range in the tert-dodecyl mercaptan have overlapping boiling points, it is difficult to separate them by using ordinary rectification.

[0004] At present, the separation purity of tetramerized propylene is only 90% and the purity of tert-dodecyl mercaptan is only 98.5% under the condition of 80 plates and a reflux ratio of 10 in the laboratory. By using this separation method, the energy consumption is high, the product purity is low, and the cost is high due to the high number of plates. SUMMARY

[0005] Based on this, the present application provides a tert-dodecyl mercaptan and tetramerized propylene separation method to improve the separation purity, increase the yield, and reduce the energy consumption and investment cost.

[0006] In a first aspect, a tert-dodecyl mercaptan and tetramerized propylene separation method is provided, comprising:

[0007] An azeotropic rectification is performed by adding an azeotrope agent into a first mixed liquid containing the tert-dodecyl mercaptan and the tetramerized propylene, a first fraction containing the tetramerized propylene and the azeotrope agent is collected, and a first residue containing the tert-dodecyl mercaptan is collected; wherein the azeotrope agent comprises one or more of C6 to C12 saturated monohydric alcohols.

[0008] The azeotrope agent, as the name implies, is an agent that can co-boil with tetrameric propylene. Through azeotropic distillation, tetrameric propylene and the azeotrope agent form a low-boiling azeotrope mixture, so that tetrameric propylene can be separated from tert-dodecyl mercaptan.

[0009] By introducing one or more of C6-C12 saturated monohydric alcohols as an azeotrope agent, the azeotrope agent and tetrameric propylene can co-boil at a lower boiling point, so that tetrameric propylene can be separated from tert-dodecyl mercaptan at a lower temperature, a lower number of trays and / or a smaller reflux ratio, thereby improving the separation purity while improving the yield, and reducing energy consumption and investment costs.

[0010] Optionally, the flow ratio of the azeotrope agent to the first mixed solution is (0.2-4):2, and optionally (0.4-0.8):2. For example, the flow ratio of the azeotrope agent to the first mixed solution can be 0.2:2, 0.3:2, 0.4:2, 0.5:2, 0.6:2, 0.7:2, 0.8:2, 0.9:2, 1:2, 2:2, 2.5:2, 3:2, 3.5:2 or 4:2.

[0011] The flow ratio of the azeotrope agent to the first mixed solution in the above range can maximize the reduction of azeotropic temperature and improve the separation effect of tert-dodecyl mercaptan and tetrameric propylene.

[0012] Optionally, the azeotrope agent comprises at least one of 2-ethylhexanol, n-hexanol, n-decanol and n-dodecanol; and optionally, the azeotrope agent comprises 2-ethylhexanol.

[0013] Optionally, the mass fraction of tetrameric propylene in the first mixed solution is 10%-20%, and the mass fraction of tert-dodecyl mercaptan in the first mixed solution is 80%-90%.

[0014] For example, the mass fraction of tetrameric propylene in the first mixed solution can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, and the mass fraction of tert-dodecyl mercaptan can be 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81% or 80%, respectively. The separation effect of tetrameric propylene and tert-dodecyl mercaptan can be maximized.

[0015] Optionally, the azeotropic distillation satisfies at least one of the following conditions:

[0016] (1) the pressure of the azeotropic distillation is 0.1 kPa to 3 kPa; optionally, 0.2 kPa to 2 kPa; for example, the pressure of the azeotropic distillation can be 0.1 kPa, 0.5 kPa, 0.8 kPa, 1 kPa, 1.5 kPa, 2 kPa, 2.5 kPa or 3 kPa; by controlling the pressure of the azeotropic distillation, the azeotropic temperature and the composition of the azeotropic mixture can be adjusted, thereby maximizing the azeotropic efficiency, improving the separation efficiency of the tetrameric propylene and the tertiary dodecyl mercaptan, and improving the separation purity of the tertiary dodecyl mercaptan;

[0017] (2) the overhead temperature of the azeotropic distillation is 108°C to 183°C; for example, the overhead temperature of the azeotropic distillation can be 108°C, 110°C, 115°C, 121°C, 125°C, 130°C, 135°C, 140°C, 150°C, 155°C, 160°C, 165°C, 170°C, 180°C or 183°C;

[0018]

[0019] for example, when the azeotropic distillation pressure is 0.1 kPa, the overhead temperature can be 108°C, and when the azeotropic distillation pressure is 2 kPa, the overhead temperature can be 155°C.

[0020] for example, when the azeotropic distillation pressure is 3 kPa, the overhead temperature can be 183°C, and when the azeotropic distillation pressure is 0.5 kPa, the overhead temperature can be 123°C.

[0021] (3) the total number of trays used in the azeotropic distillation is 20 to 30; for example, the total number of trays used in the azeotropic distillation can be 20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30; by controlling the total number of trays in the azeotropic distillation to be 20 to 30, the tertiary dodecyl mercaptan and tetrameric propylene can be separated by azeotropic distillation, and the separation purity of the tertiary dodecyl mercaptan and tetrameric propylene can be high, with the characteristics of high separation purity, low energy consumption and low investment cost; (4) the reflux ratio of the azeotropic distillation is 1 to 5, optionally 2 to 3; for example, the reflux ratio of the azeotropic distillation can be 1, 2, 3, 4 or 5; by controlling the reflux ratio of the azeotropic distillation to be 1 to 5, the azeotropic distillation effect can be maximized, and the separation purity can be improved.

[0022] Optionally, the entrainer is fed from an i-th tray, and the first mixture is fed from a j-th tray, wherein i is an i-th tray arranged in sequence from the bottom to the top of N trays, j is a j-th tray arranged in sequence from the bottom to the top of N trays, N is the total number of trays, i-j is greater than or equal to 5, and i and j are both less than or equal to 2 / N. For example, when N is 30, i can be equal to 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, and j can be equal to 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0023] Optionally, the separation method further comprises:

[0024] The first fraction is subjected to secondary rectification to separate the tetramer propylene and the entrainer, and a second fraction containing the entrainer and a second residue containing the tetramer propylene are collected. By subjecting the tetramer propylene and the entrainer to secondary rectification, the tetramer propylene and the entrainer can be separated, thereby achieving their respective recovery and recycling.

[0025] Optionally, the secondary rectification satisfies at least one of the following conditions:

[0026] (1) The pressure of the secondary rectification is 1 kPa to 100 kPa, and optionally 5 kPa to 10 kPa; for example, the pressure of the secondary rectification can be 1 kPa, 2 kPa, 3 kPa, 4 kPa, 5 kPa, 8 kPa, 10 kPa, 15 kPa, 20 kPa, 25 kPa, 30 kPa, 35 kPa, 40 kPa, 45 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa, or 100 kPa, etc. By controlling the pressure of the secondary rectification, the boiling point temperature (i.e., the top temperature) of the secondary rectification and the composition of the fraction can be adjusted, thereby maximizing the separation efficiency of the tetramer propylene and the entrainer;

[0027] (2) The top temperature of the secondary rectification is 120°C to 230°C; for example, the top temperature of the secondary rectification can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, or 230°C, etc.

[0028] Wherein, similar to the azeotropic rectification described above, the higher the pressure of the secondary rectification, the higher the top temperature, and vice versa. For example, when the pressure of the secondary rectification is 1 kPa, the top temperature can be 120°C, and when the pressure of the secondary rectification is 100 kPa, the top temperature can be 230°C.

[0029] (3) The number of plates of the secondary rectification is 10-20; by controlling the number of plates of the secondary rectification to be 10-20, the tetramer propylene and the azeotrope can be separated by rectification, and the azeotrope and the tetramer propylene with high separation purity can be obtained, which has the characteristics of high separation purity, low energy consumption and low investment cost;

[0030] (4) The reflux ratio of the secondary rectification is 0.2-3, which can be 0.5-2. By controlling the reflux ratio of the secondary rectification to be 0.2-3, the tetramer propylene and the azeotrope can be more effectively separated, thereby further improving the recovery and recycling efficiency.

[0031] Optionally, the first fraction is introduced from the mth plate, m is the mth plate arranged in turn from the bottom to the top of the S plates, S is the total number of plates, and m is less than or equal to 2 / S. For example, when S is 20, m can be equal to 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1. The separation effect of the secondary rectification can be further improved, thereby further improving the separation purity of the tetramer propylene and the azeotrope.

[0032] Optionally, the purity of the tetramer propylene in the second distillate is greater than or equal to 99.5%, and the purity of the azeotrope in the second fraction is greater than or equal to 90%. The tetramer propylene and the azeotrope can be better separated to improve their respective separation purity, thereby facilitating their subsequent high-purity use in different application scenarios.

[0033] Compared with the related art, the present application has at least the following beneficial technical effects:

[0034] By introducing one or more of C6-C12 saturated monohydric alcohols as an azeotrope, the azeotrope and the tetramer propylene can be separated at a lower boiling point, which can separate the tetramer propylene from the tert-dodecyl mercaptan at a lower temperature, a smaller number of plates and / or a smaller reflux ratio, thereby improving the separation purity while improving the yield, and reducing the energy consumption and investment cost. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present application, the present application will be described more fully below. The present application can be implemented in many different forms, and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. As used in the description herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] The application will be further described in conjunction with specific embodiments. The application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of the embodiments is to make the disclosure of the application more thorough and comprehensive.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0039] In the present application, "at least one" refers to any one, any two or any two or more of the listed items.

[0040] In the present application, "combination thereof", "any combination thereof", "any combination manner thereof" and the like include all suitable combination manners of any two or more of the listed items.

[0041] In the present application, in the technical features described in an open form, both the closed technical solution consisting of the listed features and the open technical solution containing the listed features are included.

[0042] In the present application, in relation to a numerical interval, if not specifically stated, both ends of the numerical interval are included.

[0043] In the present application, in relation to a percentage concentration, if not specifically stated, it refers to a final concentration. The final concentration refers to the proportion of the added ingredient in the system after the ingredient is added.

[0044] In the present application, in relation to a temperature parameter, if not specifically limited, both constant temperature treatment and treatment within a certain temperature range are allowed. The constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument.

[0045] In view of the problems of high energy consumption, low product purity and high investment cost due to high number of trays in the related art, the specific embodiments of the present application are described as follows:

[0046] Some embodiments of the present application provide a method for separating tertiary dodecyl mercaptan and tetrapropylene, the method comprising:

[0047] The azeotrope agent is added to the first mixed solution containing tertiary dodecyl mercaptan and tetrameric propylene for azeotrope rectification, and a first fraction containing tetrameric propylene and the azeotrope agent and a first residue containing tertiary dodecyl mercaptan are collected respectively; wherein the azeotrope agent comprises one or more of C6-C12 saturated monohydric alcohols.

[0048] In some embodiments, the first mixed solution containing tertiary dodecyl mercaptan and tetrameric propylene can be a tertiary dodecyl mercaptan reaction solution, and the raw material of the tertiary dodecyl mercaptan reaction solution can comprise tetrameric propylene, hydrogen sulfide and a catalyst. After the reaction is completed, the tertiary dodecyl mercaptan reaction solution can contain tertiary dodecyl mercaptan, incompletely reacted tetrameric propylene and a catalyst, or, after the reaction is completed, the tertiary dodecyl mercaptan reaction solution can contain tertiary dodecyl mercaptan, incompletely reacted tetrameric propylene, a catalyst, mercaptan (such as C4-C9 mercaptan, the mass fraction of which can be <0.5%) and heavy component sulfide (such as sulfide with carbon atom number >20, the mass fraction of which can be <1%), etc. All of them can be separated by the above-mentioned azeotrope rectification to realize high-efficiency separation of tertiary dodecyl mercaptan and tetrameric propylene.

[0049] In other embodiments, the first mixed solution containing tertiary dodecyl mercaptan and tetrameric propylene can be an artificial mixed solution containing tertiary dodecyl mercaptan and tetrameric propylene, and can contain low-molecular-weight mercaptan (such as C4-C9 mercaptan, the mass fraction of which can be <0.5%), low-molecular-weight sulfide (such as C4-C9 sulfide, the mass fraction of which can be <0.5%) and high-molecular-weight mercaptan (such as mercaptan with carbon atom number >20, the mass fraction of which can be <1%) and high-molecular-weight sulfide (such as sulfide with carbon atom number >20, the mass fraction of which can be <1%). All of them can be separated by the above-mentioned azeotrope rectification to realize high-efficiency separation of tertiary dodecyl mercaptan and tetrameric propylene.

[0050] The azeotrope agent, as the name implies, is a reagent that can form an azeotrope with tetrameric propylene. Through azeotrope rectification, tetrameric propylene and the azeotrope agent form a low-boiling azeotrope mixture, so as to promote the separation of tetrameric propylene from tertiary dodecyl mercaptan.

[0051] Fatty alcohols are a general term for alcohols with chain hydrocarbon groups, and the general formula is R-OH, wherein R represents a fatty hydrocarbon group. Fatty alcohols can be divided into saturated fatty alcohols and unsaturated fatty alcohols according to whether the hydrocarbon group in the alcohol molecule is saturated or not.

[0052] Saturated monohydric fatty alcohols refer to alcohol compounds containing one hydroxyl group, and the hydrocarbon group in the molecule is a saturated fatty hydrocarbon group. The general formula is C n H （2n+1） OH, wherein the hydrocarbon group can be linear or branched, the hydroxyl group can be connected to a linear carbon or a branched carbon, and the fatty alcohol can be a primary alcohol, a secondary alcohol or a tertiary alcohol, etc.

[0053] In the method for separating tert-dodecyl mercaptan and tetrapolypropylene provided in the embodiments of the present application, one or more of C6-C12 saturated monohydric alcohols are introduced as the azeotrope agent, and the azeotrope agent and tetrapolypropylene form azeotrope at a lower boiling point, so that the tetrapolypropylene can be separated from the tert-dodecyl mercaptan at a lower temperature, a smaller number of plates and / or a smaller reflux ratio, thereby improving the separation purity and yield, and reducing energy consumption and investment cost.

[0054] In some embodiments, the flow ratio of the azeotrope agent to the first mixed solution is (0.2-4):2, and optionally (0.4-0.8):2. For example, the flow ratio of the azeotrope agent to the first mixed solution can be 0.2:2, 0.3:2, 0.4:2, 0.5:2, 0.6:2, 0.7:2, 0.8:2, 0.9:2, 1:2, 2:2, 2.5:2, 3:2, 3.5:2 or 4:2.

[0055] In these embodiments, the flow ratio of the azeotrope agent to the first mixed solution is within the above range, which can maximize the azeotrope temperature and improve the separation effect of tert-dodecyl mercaptan and tetrapolypropylene.

[0056] In some examples, the flow ratio of the azeotrope agent to the first mixed solution can be 0.2 g / min:2 g / min, 0.3 g / min:2 g / min, 0.4 g / min:2 g / min, 0.5 g / min:2 g / min, 0.6 g / min:2 g / min, 0.7 g / min:2 g / min, 0.8 g / min:2 g / min, 0.9 g / min:2 g / min, 1 g / min:2 g / min, 2 g / min:2 g / min, 2.5 g / min:2 g / min, 3 g / min:2 g / min, 3.5 g / min:2 g / min or 4 g / min:2 g / min.

[0057] In some embodiments, the azeotrope agent comprises at least one of 2-ethylhexanol, n-hexanol, n-decanol and n-dodecanol; and optionally, the azeotrope agent comprises 2-ethylhexanol.

[0058] In some embodiments, the mass fraction of tetrapolypropylene in the first mixed solution is 10%-20%, and the mass fraction of tert-dodecyl mercaptan in the first mixed solution is 80%-90%.

[0059] For example, the mass percentage of the tetrameric propylene in the first mixed solution can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, and the mass percentage of the tertiary dodecyl mercaptan can be 90%, 89%, 88%, 87%, 86%, 85%, 84%, 83%, 82%, 81%, or 80% correspondingly.

[0060] In these embodiments, the separation effect of the tetrameric propylene and the tertiary dodecyl mercaptan can be maximized.

[0061] In some embodiments, the pressure of the azeotropic rectification is 0.1 kPa to 3 kPa; optionally, 0.2 kPa to 2 kPa. For example, the pressure of the azeotropic rectification can be 0.1 kPa, 0.5 kPa, 0.8 kPa, 1 kPa, 1.5 kPa, 2 kPa, 2.5 kPa, or 3 kPa.

[0062] In these embodiments, by controlling the pressure of the azeotropic rectification, the azeotropic temperature and the azeotropic mixture composition of the azeotropic rectification can be adjusted, so that the azeotropic efficiency can be maximized, the separation efficiency of the tetrameric propylene and the tertiary dodecyl mercaptan can be improved, and the separation purity of the tertiary dodecyl mercaptan can be improved.

[0063] In some embodiments, the top temperature of the azeotropic rectification is 108°C to 183°C. For example, the top temperature of the azeotropic rectification can be 108°C, 110°C, 115°C, 121°C, 125°C, 130°C, 135°C, 140°C, 150°C, 155°C, 160°C, 165°C, 170°C, 180°C, or 183°C.

[0064] In some embodiments, the top temperature of the azeotropic rectification is 108°C to 183°C. For example, the top temperature of the azeotropic rectification can be 108°C, 110°C, 115°C, 121°C, 125°C, 130°C, 135°C, 140°C, 150°C, 155°C, 160°C, 165°C, 170°C, 180°C, or 183°C.

[0065] For example, when the azeotropic agent is 2-ethylhexanol, when the pressure of the azeotropic rectification is 0.1 kPa, the top temperature can be 108°C, and when the pressure of the azeotropic rectification is 2 kPa, the top temperature can be 155°C.

[0066] In some embodiments, the total number of trays used in the azeotropic distillation is 20-30. For example, the total number of trays used in the azeotropic distillation can be 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30, etc.

[0067] In these embodiments, by controlling the total number of trays of the azeotropic distillation to be 20-30, the tert-dodecyl mercaptan and tetramers of propylene can be separated by the azeotropic distillation, and the tert-dodecyl mercaptan and tetramers of propylene with high separation purity can be obtained, which has the characteristics of high separation purity, low energy consumption and low investment cost.

[0068] In some embodiments, the reflux ratio of the azeotropic distillation is 1-5, which can be optionally 2-3. For example, the reflux ratio of the azeotropic distillation can be 1, 2, 3, 4, or 5.

[0069] In these embodiments, by controlling the reflux ratio of the azeotropic distillation to be 1-5, the azeotropic distillation effect can be maximized to improve the separation purity.

[0070] In some embodiments, the entrainer is introduced from the ith tray, and the first mixture is introduced from the jth tray, wherein i is the ith tray arranged in order from the bottom to the top of the N trays, j is the jth tray arranged in order from the bottom to the top of the N trays, N is the total number of trays, i-j is greater than or equal to 5, and both i and j are less than or equal to 2 / N.

[0071] For example, taking N as 30, i can be equal to 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15, and j can be equal to 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.

[0072] In these embodiments, the azeotropic distillation effect can be further improved, thereby improving the separation purity.

[0073] In some embodiments, the above separation method further comprises:

[0074] The tetramers of propylene and the entrainer in the first fraction are subjected to secondary distillation to collect a second fraction containing the entrainer and a second residue containing the tetramers of propylene.

[0075] In these embodiments, by subjecting the tetramers of propylene and the entrainer to secondary distillation, the tetramers of propylene and the entrainer can be separated, thereby realizing their respective recovery and recycling.

[0076] In some embodiments, the pressure of the secondary rectification is 1 kPa to 100 kPa, optionally 5 kPa to 10 kPa. For example, the pressure of the secondary rectification can be 1 kPa, 2 kPa, 3 kPa, 4 kPa, 5 kPa, 8 kPa, 10 kPa, 15 kPa, 20 kPa, 25 kPa, 30 kPa, 35 kPa, 40 kPa, 45 kPa, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa or 100 kPa, etc.

[0077] In these embodiments, by controlling the pressure of the secondary rectification, the boiling point temperature (i.e. the overhead temperature) and the composition of the fraction of the secondary rectification can be adjusted, so that the separation efficiency of the tetramer propylene and the azeotrope can be maximized.

[0078] In some embodiments, the overhead temperature of the secondary rectification is 120°C to 230°C. For example, the overhead temperature of the secondary rectification can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C or 230°C, etc.

[0079] In some embodiments, the overhead temperature of the secondary rectification is 120°C to 230°C. For example, the overhead temperature of the secondary rectification can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C or 230°C, etc.

[0080] In some embodiments, the total number of trays of the secondary rectification is 10 to 20. The inventors have found that by controlling the number of trays of the secondary rectification to be 10 to 20, the tetramer propylene and the azeotrope can be separated by rectification, and azeotrope and tetramer propylene with high separation purity can be obtained, which has the characteristics of high separation purity, low energy consumption and low investment cost.

[0081] In some embodiments, the reflux ratio of the secondary rectification is 0.2 to 3, optionally 0.5 to 2. The inventors have found that by controlling the reflux ratio of the secondary rectification to be 0.2 to 3, the tetramer propylene and the azeotrope can be more effectively separated, thereby further improving the recovery and recycling efficiency.

[0082] In some embodiments, the first fraction is introduced from the mth tray, m is the mth tray arranged in order from the bottom to the top of the S trays, S is the total number of trays, and m is less than or equal to 2 / S.

[0083] For example, with S being 20, m can be equal to 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1.

[0084] In these embodiments, the separation effect of the secondary rectification can be further improved, thereby further improving the separation purity of the tetrameric propylene and the azeotrope.

[0085] In some embodiments, the purity of the tetrameric propylene in the second distillate is greater than or equal to 99.5%, and the purity of the azeotrope in the second fraction is greater than or equal to 90%.

[0086] The purity can be obtained by gas chromatography.

[0087] In these embodiments, the tetrameric propylene and the azeotrope can be better separated, thereby improving the separation purity of each, and facilitating the subsequent use in different application scenarios with high purity.

[0088] The second fraction can be used as an azeotrope to continue separating the tertiary dodecyl mercaptan and the tetrameric propylene, without introducing other impurities.

[0089] The specific embodiments of the present application are described above. In order to objectively illustrate the technical effects of the present application, the following examples will be described.

[0090] In the following examples, all raw materials can be obtained by commercial forms, and in order to maintain the reliability of the experiment, the raw materials used in the following examples all have the same physical and chemical parameters or are subjected to the same treatment.

[0091] In the following examples, the names, related parameters and sources, and models of the main components used are as follows:

[0092] 1. Source of raw materials and catalysts:

[0093] 2-Ethylhexanol, n-hexanol, n-decyl alcohol, and n-dodecanol were purchased from alfa aesar reagent company, and the tertiary dodecyl mercaptan reaction liquid to be separated was prepared by the following method:

[0094] The tetrameric propylene and hydrogen sulfide were mixed at a molar ratio of hydrogen sulfide to tetrameric propylene of 2.5, and continuously reacted at 60°C for 700h under the catalysis of sulfonated polystyrene-based resin, to obtain the tertiary dodecyl mercaptan reaction liquid to be separated. According to different reaction batches, the conversion rate of tetrameric propylene in the tertiary dodecyl mercaptan reaction liquid to be separated is different.

[0095] The mass proportions of C10 olefins, C11 olefins, C12 olefins, C13 olefins and C14 olefins in the tetramerized propylene raw material are 1.5%, 8.5%, 71%, 15% and 4% respectively. The catalyst: sulfonated polystyrene-based resin is purchased from Dow Chemical.

[0096] 2. Analysis method:

[0097]

[0098] Chromatographic column: DB-5, HP-5 or wax chromatographic column, gas chromatography analysis method, column temperature 50℃, holding for 5min, temperature rising to 220℃ at 10℃ / min; FID detector detection, sample size 0.5μL.

[0099] 3. The conditions of azeotropic rectification and recovery rectification in Examples 1-4 are shown in Table 1 below.

[0100] Table 1

[0101]

[0102] Example 1

[0103] Example 1 provides a method for separating tertiary dodecyl mercaptan and tetramerized propylene, which comprises the following steps:

[0104] (1) Take the reaction liquid of the tertiary dodecyl mercaptan to be separated, and detect by gas chromatography to obtain the mass proportion of tetramerized propylene in the reaction liquid, which is 18wt%, and the mass proportion of tertiary dodecyl mercaptan, which is 82wt%, wherein the mass proportions of the reaction products of tertiary dodecyl mercaptan corresponding to C10 olefins, C11 olefins, C12 olefins, C13 olefins and C14 olefins in the reaction liquid are 1.23%, 6.97%, 58.22%, 12.3% and 3.28% respectively.

[0105] (2) Provide an azeotropic rectification column with a total number of plates of 20, which are the 1st plate, the 2nd plate, …, the 10th plate, …, the 19th plate and the 20th plate from the bottom to the top of the column.

[0106] The reaction liquid of the tertiary dodecyl mercaptan to be separated is introduced into the azeotropic rectification tower with a total number of 20 tower plates through the feed inlet of the 10th tower plate at a flow rate of 2 g / min, and the azeotropic agent 2-ethylhexanol is introduced into the azeotropic rectification tower through the feed inlet of the 5th tower plate at a flow rate of 0.2 g / min. The pressure in the azeotropic rectification tower is controlled at 0.1 kPa, the overhead temperature is 108°C, and the reflux ratio is 1. The mixture of tetrameric propylene and 2-ethylhexanol is obtained at the top of the azeotropic rectification tower; the purity of the tertiary dodecyl mercaptan obtained at the bottom of the azeotropic rectification tower is 99.5%, the flow rate is 1.632 g / min, and the yield is 99.5%, which is calculated by the formula 1.632 / (2*0.82); wherein the purity of the reaction product of the respective tertiary dodecyl mercaptan corresponding to C10 olefin, C11 olefin, C12 olefin, C13 olefin and C14 olefin in the tertiary dodecyl mercaptan with a purity of 99.5% is 1.2%, 8.3%, 71.1%, 15.0% and 3.9%, respectively.

[0107] (3) A recovery rectification tower with a total number of 10 tower plates is provided, and the 10 tower plates are sequentially arranged from the bottom to the top as the 1st tower plate, the 2nd tower plate, …, the 5th tower plate, …, the 9th tower plate and the 10th tower plate.

[0108] The mixture of tetrameric propylene and 2-ethylhexanol obtained in step (2) is introduced into the recovery rectification tower with a total number of 10 tower plates through the feed inlet of the 5th tower plate at a flow rate of 2 g / min, and the separation of tetrameric propylene and 2-ethylhexanol is carried out. The pressure in the recovery rectification tower is controlled at 1 kPa, the overhead temperature is 120°C, and the reflux ratio is 0.2. The mixture of 2-ethylhexanol with a purity of 95wt% and tetrameric propylene with a purity of 5wt% is obtained at the top of the recovery rectification tower, which can be recycled as an azeotropic agent. The purity of the tetrameric propylene obtained at the bottom of the recovery rectification tower is 99.9wt%, the flow rate is 0.347 g / min, and the yield is 96.4%, which is calculated by the formula 0.347 / (2*0.18).

[0109] Example 2

[0110] Example 2 provides a method for separating tertiary dodecyl mercaptan and tetrameric propylene, which comprises the following steps:

[0111] (1) Take the tertiary dodecyl mercaptan reaction liquid to be separated, and detect by gas chromatography to obtain that the mass fraction of tetramer propylene in the reaction liquid is 15wt%, and the mass fraction of tertiary dodecyl mercaptan is 85wt%, wherein the mass fractions of the reaction products of the respective tertiary dodecyl mercaptan and C10 olefin, C11 olefin, C12 olefin, C13 olefin and C14 olefin in the reaction liquid are 1.28%, 7.22%, 60.35%, 12.75% and 3.4% respectively.

[0112] (2) Provide an azeotropic rectification tower with a total number of 30 plates, and the 30 plates are sequentially from the bottom to the top of the tower as the 1st plate, the 2nd plate, …, the 10th plate, …, the 29th plate and the 30th plate.

[0113] The tertiary dodecyl mercaptan reaction liquid to be separated is introduced into the azeotropic rectification tower with a total number of 30 plates through the feed inlet of the 12th plate of the azeotropic rectification tower at a flow rate of 2g / min, and the azeotrope n-hexanol is introduced into the azeotropic rectification tower through the feed inlet of the 7th plate of the azeotropic rectification tower at a flow rate of 4g / min. The pressure in the azeotropic rectification tower is controlled at 3kPa, the top temperature is 183℃, the reflux ratio is 5, and the mixed liquid of tetramer propylene and n-hexanol is obtained at the top of the azeotropic rectification tower; tested by a gas chromatograph, the purity of the tertiary dodecyl mercaptan obtained at the bottom of the azeotropic rectification tower is 99.5%, the flow rate is 1.688g / min, the yield is 99.3%, which is calculated by the formula 1.688 / (2*0.85); wherein the purities of the reaction products of the respective tertiary dodecyl mercaptan and C10 olefin, C11 olefin, C12 olefin, C13 olefin and C14 olefin in the reaction liquid are 1.4%, 8.3%, 71.0%, 14.9% and 3.9% respectively.

[0114] (3) Provide a recovery rectification tower with a total number of 20 plates, and the 15 plates are sequentially from the bottom to the top of the tower as the 1st plate, the 2nd plate, …, the 10th plate, …, the 19th plate and the 20th plate.

[0115] The mixture of tetrapolypropylene and n-hexanol obtained in step (2) was introduced into a recovery rectification column with a total number of 20 plates through the feed inlet of the 9th plate at a flow rate of 2 g / min to separate the tetrapolypropylene and n-hexanol. The pressure in the recovery rectification column was controlled at 100 kPa, the overhead temperature was 230°C, and the reflux ratio was 3. The mixture of n-hexanol with a purity of 99 wt% and tetrapolypropylene with a purity of 1 wt% obtained at the top of the recovery rectification column was recycled as an azeotrope, and tetrapolypropylene with a purity of 99.7 wt% was obtained at the bottom of the recovery rectification column at a flow rate of 0.237 g / min, with a yield of 79.0%, which was calculated by the formula 0.237 / (2*0.15).

[0116] Example 3

[0117] Example 3 provides a method for separating tertiary dodecyl mercaptan and tetrapolypropylene, which comprises the following steps:

[0118] (1) A reaction solution of tertiary dodecyl mercaptan to be separated was taken, and gas chromatography detection showed that the mass fraction of tetrapolypropylene in the reaction solution was 10 wt%, and the mass fraction of tertiary dodecyl mercaptan was 90 wt%, wherein the mass fractions of the reaction products of tertiary dodecyl mercaptan corresponding to C10 olefins, C11 olefins, C12 olefins, C13 olefins and C14 olefins in the reaction solution were 1.35%, 7.65%, 63.9%, 13.5% and 3.6%, respectively.

[0119] (2) An azeotropic rectification column with a total number of 25 plates was provided, and the 25 plates were sequentially numbered as the 1st plate, the 2nd plate, …, the 10th plate, …, the 24th plate and the 25th plate from the bottom to the top of the column.

[0120] The reaction liquid of the tertiary dodecyl mercaptan to be separated is introduced into the azeotropic rectification tower with a total number of 25 tower plates through the feed inlet of the 10th tower plate at a flow rate of 2 g / min, and the azeotropic agent n-decanol is introduced into the azeotropic rectification tower through the feed inlet of the 5th tower plate at a flow rate of 0.4 g / min. The pressure in the azeotropic rectification tower is controlled at 0.2 kPa, the overhead temperature is 121°C, and the reflux ratio is 2. The mixed liquid of tetrameric propylene and n-decanol is obtained at the top of the azeotropic rectification tower; the purity of the tertiary dodecyl mercaptan obtained at the bottom of the azeotropic rectification tower is 99.5%, the flow rate is 1.793 g / min, and the yield is 99.6%, which is calculated by the formula 1.793 / (2*0.90); wherein the purities of the reaction products of the tertiary dodecyl mercaptan corresponding to C10 olefins, C11 olefins, C12 olefins, C13 olefins and C14 olefins in the tertiary dodecyl mercaptan with a purity of 99.5% are 1.4%, 8.3%, 71.0%, 14.9% and 3.9%, respectively.

[0121] (3) A recovery rectification tower with a total number of 15 tower plates is provided, and the 15 tower plates are sequentially arranged from the bottom to the top as the 1st tower plate, the 2nd tower plate, …, the 10th tower plate, …, the 14th tower plate and the 15th tower plate.

[0122] The mixed liquid of tetrameric propylene and n-decanol obtained in step (2) is introduced into the recovery rectification tower with a total number of 15 tower plates through the feed inlet of the 7th tower plate at a flow rate of 2 g / min to separate the tetrameric propylene and n-decanol. The pressure in the recovery rectification tower is controlled at 5 kPa, the overhead temperature is 159°C, and the reflux ratio is 0.5. The mixed liquid of n-decanol with a purity of 94wt% and tetrameric propylene with a purity of 6wt% is obtained at the top of the recovery rectification tower, which is recycled as an azeotropic agent. The purity of the tetrameric propylene obtained at the bottom of the recovery rectification tower is 99.8wt%, the flow rate is 0.16 g / min, and the yield is 80.0%, which is calculated by the formula 0.16 / (2*0.1).

[0123] Example 4

[0124] Example 4 provides a method for separating tertiary dodecyl mercaptan and tetrameric propylene, which comprises the following steps:

[0125] (1) Take the reaction solution of tert-dodecyl mercaptan to be separated and detect it by gas chromatography. The mass percentage of tetrapropylene in the reaction solution is 20 wt%, and the mass percentage of tert-dodecyl mercaptan is 80 wt%. The mass percentages of the reaction products of tert-dodecyl mercaptan corresponding to C10 olefin, C11 olefin, C12 olefin, C13 olefin and C14 olefin in the reaction solution are 1.2%, 6.8%, 56.8%, 12% and 3.2%, respectively.

[0126] (2) Provide an azeotropic distillation column with a total of 25 trays, which are arranged from bottom to top as tray 1, tray 2, ..., tray 10, ..., tray 24 and tray 25.

[0127] The reaction solution of tert-dodecyl mercaptan to be separated was introduced into an azeotropic distillation column with a total of 25 trays through the feed inlet of the 10th tray of the azeotropic distillation column at a flow rate of 2 g / min. The azeotropic agent n-dodecyl alcohol was introduced into the azeotropic distillation column through the feed inlet of the 3rd tray of the azeotropic distillation column at a flow rate of 0.8 g / min. The pressure inside the azeotropic distillation column was controlled at an absolute pressure of 2 kPa, the top temperature at 155℃, and the reflux ratio at 3. A mixture of tetrapropylene and n-dodecyl alcohol was obtained at the top of the azeotropic distillation column. Gas chromatography analysis showed that tert-dodecyl mercaptan with a purity of 99.8% was obtained at the bottom of the azeotropic distillation column at a flow rate of 1.592 g / min, with a yield of 99.5%, calculated using the formula 1.592 / (2*0.8). Among them, the purities of the reaction products of C10 olefins, C11 olefins, C12 olefins, C13 olefins, and C14 olefins in the 99.5% pure tert-dodecyl mercaptan in the reaction solution were 1.2%, 8.3%, 71.1%, 15.0%, and 3.9%, respectively.

[0128] (3) Provide a recovery distillation column with a total of 15 trays, which are arranged from bottom to top as tray 1, tray 2, ..., tray 10, ..., tray 14 and tray 15.

[0129] The mixture of tetrapolypropylene and n-dodecanol obtained in step (2) was introduced into a recovery rectification column with a total number of 15 plates at a flow rate of 2 g / min through the feed inlet of the 5th plate, and the separation of tetrapolypropylene and n-dodecanol was carried out. The pressure in the recovery rectification column was controlled at 10 kPa, the overhead temperature was 172℃, and the reflux ratio was 2. The mixture of n-dodecanol with a purity of 91wt% and tetrapolypropylene with a purity of 9wt% was obtained at the top of the recovery rectification column, which was recycled as an azeotrope, and tetrapolypropylene with a purity of 99.8wt% was obtained at the bottom of the recovery rectification column, with a flow rate of 0.39 g / min and a yield of 97.5%, which was calculated by the formula 0.39 / (2*0.2).

[0130] As can be seen from Examples 1 to 4, by selecting an azeotrope and tetrapolypropylene for azeotropic rectification, tetrapolypropylene and tertiary dodecyl mercaptan can be separated, and the separation purity and yield can be improved, and the energy consumption and investment cost can be reduced. By recycling the mixture of the azeotrope and tetrapolypropylene, the azeotrope and tetrapolypropylene can be separated, and tetrapolypropylene and the azeotrope with high purity can be obtained, and the azeotrope can be recycled.

[0131] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0132] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent application of the present application should be subject to the appended claims.

Claims

1. A method for separating tertiary dodecyl mercaptan and tetramers of propylene, characterized in that, The method comprises: adding an azeotrope agent to the first mixture containing the tertiary dodecyl mercaptan and the tetrameric propylene for azeotropic distillation, collecting a first fraction containing the tetrameric propylene and the azeotrope agent, and a first residue containing the tertiary dodecyl mercaptan; wherein the azeotrope agent comprises one or more of C6-C12 saturated monohydric alcohols.

2. The method of separating tertiary dodecyl mercaptan and tetramers of propylene according to claim 1, characterized in that, The flow ratio of the azeotrope agent to the first mixture is (0.2-4):2, or (0.4-0.8):

2.

3. The method of separating tertiary dodecyl mercaptan and tetramers of propylene according to claim 1, characterized in that, The azeotrope agent comprises at least one of 2-ethylhexanol, n-hexanol, n-decanol, and n-dodecanol; or the azeotrope agent comprises 2-ethylhexanol.

4. The method of separating tertiary dodecyl mercaptan and tetramers of propylene of claim 1, wherein, The mass fraction of the tetrameric propylene in the first mixture is 10%-20%, and the mass fraction of the tertiary dodecyl mercaptan in the first mixture is 80%-90%.

5. The method of separating tertiary dodecyl mercaptan and tetramers of propylene of claim 1, wherein, The azeotropic distillation satisfies at least one of the following conditions: (1) the pressure of the azeotropic distillation is 0.1 kPa-3 kPa, or 0.2 kPa-2 kPa; (2) the top temperature of the azeotropic distillation is 108°C-183°C; (3) the total number of plates used in the azeotropic distillation is 20-30; (4) the reflux ratio of the azeotropic distillation is 1-5, or 2-3.

6. The method of separating tertiary dodecyl mercaptan and tetramers of propylene of claim 1, wherein, The azeotrope agent is fed from the ith plate, and the first mixture is fed from the jth plate, wherein i is the ith plate arranged in order from the bottom to the top of N plates, j is the jth plate arranged in order from the bottom to the top of N plates, N is the total number of plates, i-j is greater than or equal to 5, and both i and j are less than or equal to 2 / N.

7. The process for the separation of tertiary dodecyl mercaptan and tetrameric propylene according to any one of claims 1 to 6, characterized in that, The separation method further comprises: subjecting the tetrameric propylene and the azeotrope agent in the first fraction to secondary distillation to collect a second fraction containing the azeotrope agent and a second residue containing the tetrameric propylene.

8. The method of separating tertiary dodecyl mercaptan and tetramers of propylene according to claim 7, characterized in that, The secondary distillation satisfies at least one of the following conditions: (1) the pressure of the secondary distillation is 1 kPa-100 kPa, or 5 kPa-10 kPa; (2) the top temperature of the secondary distillation is 120°C-230°C; (3) the number of plates of the secondary distillation is 10-20; (4) the reflux ratio of the secondary distillation is 0.2-3, or 0.5-2.

9. The method of separating tertiary dodecyl mercaptan and tetramers of propylene of claim 7, wherein, The first fraction is fed from the mth plate, and m is the mth plate arranged in order from the bottom to the top of S plates, S is the total number of plates, and m is less than or equal to 2 / S.

10. The method of separating tertiary dodecyl mercaptan and tetramers of propylene of claim 7, wherein, The purity of the tetrameric propylene in the second residue is greater than or equal to 99.5%, and the purity of the azeotrope agent in the second fraction is greater than or equal to 90%.

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