Method for preparing thiols using nickel-molybdenum catalysts

Abstract

A method for synthesizing thiols includes the following steps: contacting a nickel-molybdenum catalyst with H2S at a sulfidation temperature of less than or equal to 235°C to form a supported sulfur-containing catalyst, and then contacting an alcohol or olefin compound, H2S and the supported sulfur-containing catalyst to form a reaction mixture containing the thiols.

Description

[0001] This application was filed as an international patent application on October 5, 2021, and claims the benefit and priority of U.S. Provisional Patent Application No. 63 / 088,494, filed on October 7, 2020, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] This disclosure relates to a method for producing thiols from H2S and alcohols or olefins reacted in the presence of a supported sulfur-containing nickel-molybdenum catalyst. Background Technology

[0003] Thiol compounds (also known as mercapto compounds) can be prepared by various synthetic techniques, but typically in relatively low yields or with significant byproducts. Therefore, this invention generally relates to a catalytic method for producing thiol (or mercapto) compounds in high yields and with minimal reaction byproducts. Summary of the Invention

[0004] This summary is provided to introduce selected concepts in a simplified form, which are further described below in the detailed description. This summary is not intended to identify essential or fundamental features of the claimed subject matter. Nor is it intended to be used to limit the scope of the claimed subject matter.

[0005] This document discloses methods for producing thiol compounds. In one aspect, a first method for producing thiol (or mercapto) compounds may include (i) contacting a nickel-molybdenum catalyst with H₂S at a sulfidation temperature of less than or equal to about 235°C to form a supported sulfur-containing catalyst, and (ii) contacting an alcohol compound, H₂S, and the supported sulfur-containing catalyst to form a reaction mixture comprising the thiol compound. In another aspect, a second method for producing thiol compounds may include (i) contacting a nickel-molybdenum catalyst with H₂S at a sulfidation temperature of less than or equal to about 235°C to form a supported sulfur-containing catalyst, and (ii) contacting an olefin compound, H₂S, and the supported sulfur-containing catalyst to form a reaction mixture comprising the thiol compound.

[0006] Although not limited thereto, supported sulfur-containing catalysts may contain a solid support, about 1 to about 5% by weight of nickel, about 4 to about 18% by weight of molybdenum, and about 3 to about 18% by weight of sulfur. In addition, prior to step (ii), supported sulfur-containing catalysts typically contain less than or equal to about 3% by weight of carbon.

[0007] The foregoing summary and the following detailed description are illustrative and provided as examples. Therefore, the foregoing summary and the following detailed description should not be considered limiting. Furthermore, other features or variations may be provided in addition to those listed herein. For example, certain aspects may be addressed with respect to various combinations and sub-combinations of features described in the detailed description.

[0008] definition

[0009] To more clearly define the terms used herein, the following definitions are provided. Unless otherwise specified, the following definitions apply to this disclosure. If a term is used in this disclosure but is not specifically defined herein, the definition in the IUPAC Compendium of Chemical Terminology, 2nd Edition (1997) may be applied, provided that the definition does not conflict with any other disclosure or definition applied herein, or render any claim to which the definition applies ambiguous or invalid. If any definition or usage provided in any document incorporated herein by reference conflicts with the definition or usage provided herein, the definition or usage provided herein shall prevail.

[0010] In this document, the features of the subject matter are described such that combinations of different features are conceivable within a particular aspect. For each aspect and feature disclosed herein, all combinations that will not adversely affect the compounds, compositions, processes, or methods described herein are considered, whether explicitly described or not. Furthermore, unless otherwise expressly stated, any aspect or feature disclosed herein may be combined to describe inventive compounds, compositions, processes, or methods consistent with this disclosure.

[0011] Generally, element groups are indicated using the numbering scheme indicated in the version of the periodic table published in Chemical and Engineering News, 63(5), 27, 1985. In some cases, element groups may be indicated using the common names assigned to the group; for example, alkali metals indicate Group 1 elements, alkaline earth metals indicate Group 2 elements, transition metals indicate Groups 3–12 elements, and halogens or halide ions indicate Group 17 elements.

[0012] As used herein, a "thiol" or "thiol" compound is a compound having a -SH group and may also be referred to herein as a "thiol" compound. The term "hydrocarbon" refers to a compound containing only carbon and hydrogen, whether saturated or unsaturated. Other identifiers may be used to indicate the presence of a specific group in a hydrocarbon (e.g., a halohydrocarbon indicates the presence of one or more halogen atoms in a hydrocarbon with an equal amount of hydrogen atoms). The term "hydrocarbon group" is used herein according to the definition provided by IUPAC: a monovalent group (i.e., a group containing only carbon and hydrogen) formed by removing a hydrogen atom from a hydrocarbon. Non-limiting examples of hydrocarbon groups include alkyl, alkenyl, aryl, and aralkyl groups, etc.

[0013] For any particular compound or group disclosed herein, unless otherwise stated, any name or structure presented (generally or specifically) is intended to cover all conformational isomers, positional isomers, stereoisomers, and mixtures thereof that can be produced by a particular set of substituents. Unless otherwise specified, the name or structure (generally or specifically) also covers all enantiomers, diastereomers, and other optical isomers (if any) in enantiomeric or racemic forms that would be recognized by those skilled in the art, as well as mixtures of stereoisomers. For example, general references to pentane include n-pentane, 2-methylbutane, and 2,2-dimethylpropane; and general references to butyl include n-butyl, sec-butyl, isobutyl, and tert-butyl.

[0014] Unless otherwise specified, the term "substituted" is used to describe a group, for example, when referring to a substituted analogue of a particular group, intended to describe any non-hydrogen portion that formally substitutes for hydrogen in said group, and is intended to be non-limiting. Furthermore, unless otherwise specified, one or more groups may also refer herein to "unsubstituted" or equivalent terms such as "unreplaced," which means an original group in which the non-hydrogen portion does not replace hydrogen within said group. Moreover, unless otherwise specified, "substituted" is intended to be non-limiting and includes inorganic or organic substituents as understood by one of ordinary skill in the art.

[0015] Unless otherwise stated, the terms "contact product," "contact," etc., are used herein to describe methods and compositions in which components are contacted together in any order, in any manner, and for any duration. For example, components may be contacted by blending or mixing. Furthermore, unless otherwise stated, contact of any components may occur in the presence or absence of any other components of the methods and compositions described herein. Additional materials or components may be combined by any suitable method. Additionally, the term "contact product" includes mixtures, blends, solutions, slurries, reaction products, etc., or combinations thereof. Although "contact product" may include and often includes reaction products, it does not require that the individual components react with each other. Thus, depending on the circumstances, "contact product" may be a mixture, a reaction mixture, or a reaction product. Similarly, "contacting" two or more components may produce a reaction product or a reaction mixture.

[0016] In this disclosure, although compositions and methods are described in a manner that "comprises" various components or steps, compositions and methods may also "consist substantially of" or "compose of" various components or steps unless otherwise indicated.

[0017] The terms “a / an” and “the” are intended to include multiple alternatives, such as at least one. For example, unless otherwise specified, the publicly disclosed intent of “catalyst” covers a single catalyst or a mixture or combination of more than one catalyst.

[0018] This invention discloses several types of scopes. When any type of scope is disclosed or claimed, it is intended to individually disclose or claim every possible number that such scope could reasonably cover, including the endpoints of the scope and any sub-scopes and combinations thereof covered therein. For example, when a chemical moiety having a certain number of carbon atoms is disclosed or claimed, it is intended to individually disclose or claim every possible number that the scope might cover that conforms to the disclosure herein. For example, as used herein, a moiety is C1 to C2. 18 Alkyl, or in other words, alkyl having 1 to 18 carbon atoms, refers to portions that may have 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms, and any range between these two numbers (e.g., C1 to C8 alkyl), and also includes any combination of ranges between these two numbers (e.g., C2 to C4 and C5). 12 To C 16 alkyl).

[0019] Similarly, another representative example follows the molar ratio of H2S to olefins consistent with aspects of the invention. The disclosure that the molar ratio can range from about 5:1 to about 20:1 is intended to state that the molar ratio can be any ratio within that range, and for example, can be equal to about 5:1, about 6:1, about 8:1, about 10:1, about 12:1, about 14:1, about 16:1, about 18:1, or about 20:1. Furthermore, the molar ratio can be in any range from about 5:1 to about 20:1 (e.g., about 10:1 to about 15:1), and this also includes any combination of the range from about 5:1 to about 20:1 (e.g., the ratio can be in the range from about 5:1 to about 10:1, or about 15:1 to about 20:1). Moreover, in all cases, if "about" is disclosed for a particular value, then that value itself is disclosed. Therefore, the disclosure of molar ratios from about 5:1 to about 20:1 also discloses molar ratios from 5:1 to 20:1 (e.g., from 10:1 to 15:1), and this also includes any combination of the range between 5:1 and 20:1 (e.g., the ratio may be in the range of 5:1 to 10:1 or 15:1 to 20:1). Similarly, all other ranges disclosed herein should be interpreted in a manner similar to these examples.

[0020] The term "about" means that quantities, sizes, formulations, parameters, and other quantities and characteristics are not and need not be precise, but can be approximate, including being larger or smaller as needed, reflecting tolerances, conversion factors, rounding, measurement errors, and other factors known to those skilled in the art. Generally, quantities, sizes, formulations, parameters, or other quantities or characteristics are "about" or "approximate" regardless of whether they are explicitly stated as such. The term "about" also covers quantities that vary due to different equilibrium conditions of the composition produced from a particular initial mixture. The claims include equivalent quantities, whether or not modified by the term "about." The term "about" can mean within 10% of a reported value, and often within 5% of a reported value.

[0021] Unless otherwise expressly stated, all disclosed product yields are based on the limiting reactant in the corresponding reaction. For example, the limiting reactant in the methods disclosed herein may be an alcohol (or olefin), and therefore, conversion and yield are based on the initial amount of the alcohol (or olefin).

[0022] Although any methods, apparatus, and materials similar to or equivalent to those described herein may be used in the practice or testing of this invention, typical methods, apparatus, and materials are described herein.

[0023] All publications and patents mentioned herein are incorporated herein by reference for the purpose of describing and disclosing, for example, the constructs and methods described in the publications, which may be used in conjunction with the inventions described herein. Detailed Implementation

[0024] This article discloses a method for producing thiols using a sulfur-containing nickel-molybdenum catalyst at a reaction temperature comparable to or lower than that of a cobalt-molybdenum catalyst. The method has improved alcohol or olefin conversion, increased thiols yield and selectivity, and reduced sulfide byproducts.

[0025] Synthetic thiols

[0026] Thiol compounds can be produced via two common synthetic routes. Consistent with some aspects of the present invention, a first method for producing thiols may include (i) contacting a nickel-molybdenum catalyst with H₂S at a sulfidation temperature less than or equal to about 235°C to form a supported sulfur-containing catalyst, and (ii) contacting an alcohol compound, H₂S, and said supported sulfur-containing catalyst to form a reaction mixture comprising said thiols compound. In the first method, the thiols compound may have the formula (A): R 1 –SH, alcohol compounds can have formula (B): R 1 –OH, and R 1 It can be C1 to C 18 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl groups. Consistent with other aspects of the invention, a second method for producing thiols may include (i) contacting a nickel-molybdenum catalyst with H₂S at a sulfidation temperature less than or equal to about 235°C to form a supported sulfur-containing catalyst, and (ii) contacting an olefin compound, H₂S, and said supported sulfur-containing catalyst to form a reaction mixture comprising said thiols. In the second method, the thiols may have the formula (C): R 2 –SH, olefin compounds can have the formula C=C or formula (D): R 1 –C=C,R 1 It can be C1 to C 18 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl, and R 2 It can be C3 to C 20 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl groups. Those skilled in the art will recognize that R in the second method... 1 and R 2 The choice is relevant. For example, if R in equation (D) 1 If it is a C4 alkyl group, then R in formula (C) 2 It is a C6 alkyl group.

[0027] Generally, the features of the first and second methods for producing thiols (e.g., conditions for forming a supported sulfur-containing catalyst, specific alcohol and olefin reactants, and conditions for forming the thiols, etc.) are described independently herein, and these features may be combined in any combination to further describe the disclosed first and second methods for producing thiols. Furthermore, unless otherwise stated, additional process steps may be performed before, during, and / or after the steps of these methods, and may be used without limitation and in any combination to further describe the first and second methods.

[0028] Formulas (A), (B), (C), and (D) are not intended to show stereochemical or isomeric positioning of the different parts (e.g., these formulas are not intended to show cis or trans isomers), although these formulas consider and cover such compounds. In these formulas, R 1 It can be C1 to C 18 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl, and R 2 It can be C3 to C 20 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl. For example, in one aspect, R 1 It can be C1 to C 14 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl, while on the other hand, R 1 It can be C1 to C 12 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl, and on the other hand, R 1 It can be a C1 to C8 substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl.

[0029] Consistent with aspects of the present invention, R 1 and R 2 It can be cycloalkyl; alternatively, R 1 and R 2 It may be a straight-chain alkyl group; or alternatively, R 1 and R 2 It can be a branched alkyl group. Regardless of R 1 and R 2 It is a cyclic, straight-chain or branched alkyl group, R 1 and R 2 It can be unsubstituted, or it can be substituted by any suitable substituent, any suitable number of substituents, and at any suitable position that conforms to the rules of chemical valence.

[0030] In certain aspects of the invention, R 1 It can be C1 to C 18 Straight-chain or branched alkyl groups. Therefore, R 1 It can be C1 to C 14 Straight-chain or branched alkyl groups, C1 to C 12Straight-chain or branched alkyl groups, C1 to C8 straight-chain or branched alkyl groups, or C1 to C6 straight-chain or branched alkyl groups. Therefore, in some aspects, R 1 It may be methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptyl or octadecyl; or alternatively, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl or dodecyl.

[0031] In other respects, these formulas can be used as R. 1 The alkyl group may be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, tert-pentyl, n-hexyl, n-heptyl, n-octyl, or n-dodecyl; alternatively, methyl, ethyl, or isopropyl; alternatively, methyl or ethyl; alternatively, methyl; alternatively, ethyl; alternatively, n-propyl; alternatively, isopropyl; alternatively, n-butyl; alternatively, isobutyl; alternatively, sec-butyl; alternatively, tert-butyl; alternatively, n-pentyl; alternatively, isopentyl; alternatively, sec-pentyl; alternatively, neopentyl; alternatively, tert-pentyl; alternatively, n-hexyl; alternatively, n-heptyl; alternatively, n-octyl; or alternatively, n-dodecyl.

[0032] In other aspects of the invention, R 1 It can be a cycloalkyl group. Therefore, R 1 It can be C3 to C 18 cycloalkyl, C4 to C 12 cycloalkyl, C4 to C 10 Cycloalkyl or C5 to C8 cycloalkyl. Therefore, in some respects, R in these formulas... 1 It may be cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl; alternatively, cyclobutyl; alternatively, cyclopentyl; alternatively, cyclohexyl; alternatively, cycloheptyl; or alternatively, cyclooctyl.

[0033] According to another aspect of the invention, any alkyl group (cycloalkyl, straight-chain alkyl, or branched-chain alkyl) disclosed herein may be substituted with one or more substituents. Each non-hydrogen substituent of the substituted alkyl group may independently be C1 to C1. 18 Hydrocarbon group; alternatively, C1 to C8 hydrocarbon group; or alternatively, C1 to C6 hydrocarbon group. Therefore, the hydrocarbon substituent can be benzyl, phenyl, tolyl, or xylyl, etc., and thus, R in these formulas... 1 and R 2 For example, alkyl groups can be phenyl-substituted. Additionally, the hydrocarbon substituents can be C1 to C6 straight-chain or branched alkyl groups, and therefore, the R in these formulas... 1 and R 2 It can be, for example, an alkyl-substituted cycloalkyl group, such as methylcyclohexyl.

[0034] Illustrative and non-limiting examples of alcohol compounds that can be used in the first method for producing thiols include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecylol, dodecanol, tridecanol, tetradecanol, pentadecylol, hexadecylol, heptadecanol, octadecylol, cyclopentanol, cyclohexanol, and combinations thereof. Similarly, illustrative and non-limiting examples of olefin compounds that can be used in the second method for producing thiols include ethylene, propylene, butene, pentene, hexene, hepten, octene, decene, dodecene, tetradecanol, hexadecene, octadecene, cyclopentene, cyclohexene, and combinations thereof.

[0035] Therefore, illustrative and non-limiting examples of thiols that can be prepared using the methods disclosed herein may include methanethiol, ethanethiol, isopropanethiol, sec-butanethiol, and combinations thereof.

[0036] Step (i) in the first and second methods for producing thiols may include contacting a nickel-molybdenum catalyst with H₂S at a sulfidation temperature of less than or equal to about 235°C to form a supported sulfur-containing catalyst. While not wishing to be bound by theory, it is believed that the nickel-molybdenum catalyst first requires a sulfidation step to form a supported sulfur-containing catalyst, which will then effectively react the alcohol or olefin compound with H₂S in the presence of the supported sulfur-containing catalyst to form a reaction mixture comprising said thiols. Hereinafter, an efficient method for sulfidation of a base catalyst has been found to include contacting a nickel-molybdenum catalyst with H₂S at a sulfidation temperature of less than or equal to about 235°C to form a supported sulfur-containing catalyst, and this sulfidation step can lead to the surprisingly high alcohol / olefin conversion and thiol yield disclosed herein.

[0037] In step (i), the nickel-molybdenum catalyst may be contacted with H2S at a sulfidation temperature of less than or equal to about 235°C to form a supported sulfur-containing catalyst. This sulfidation step may be carried out at any suitable temperature or lower for any suitable time period. Representative and non-limiting ranges of sulfidation temperatures in step (i) may include about 60°C to about 235°C, about 40°C to about 100°C, about 80°C to about 225°C, about 80°C to about 180°C, about 110°C to about 235°C, about 110°C to about 200°C, or about 110°C to about 160°C. These temperature ranges are also intended to cover the case where step (i) is performed at a series of different temperatures rather than at a single fixed temperature falling within its respective temperature range, wherein at least one temperature is within the listed range.

[0038] In one aspect, due to the exothermic nature of sulfidation, step (i) may include contacting the nickel-molybdenum catalyst with inlet H2S at a very low inlet sulfidation temperature, said inlet sulfidation temperature being in the range of about 10°C to about 90°C, about 20°C to about 80°C, about 20°C to about 60°C, or about 35°C to about 70°C, etc.

[0039] Similarly, there is no particular limitation on the time period of vulcanization step (i), and it can be carried out for any suitable time period. In some aspects, the time period can be at least about 1 minute, at least about 5 minutes, at least about 10 minutes, at least about 30 minutes, at least about 1 hour, at least about 2 hours, at least about 5 hours, or at least about 10 hours. In other aspects, the time period can be from about 30 seconds to about 48 hours, from about 1 minute to about 24 hours, from about 5 minutes to about 8 hours, from about 30 minutes to about 8 hours, or from about 1 hour to about 6 hours.

[0040] The sulfidation of step (i) and the catalyst can be carried out at a sulfidation pressure of about 50 to about 250 psig (344 to 1720 kPag), but is not limited thereto. Other representative and non-limiting ranges of sulfidation pressure may include about 50 to about 200 psig (344 to 1379 kPag), about 100 to about 250 psig (689 to 1720 kPag), about 100 to about 200 psig (689 to 1379 kPag), or about 100 to about 150 psig (689 to 1034 kPag).

[0041] Typically, prior to sulfidation, the nickel-molybdenum catalyst is essentially sulfur-free, but after sulfidation in step (i), the supported sulfur-containing catalyst may typically contain about 3 to about 18 wt% sulfur, for example, about 4 to about 17 wt%, about 5 to about 15 wt%, or about 7 to about 13 wt% sulfur. The amount of sulfur is based on the total weight of the supported sulfur-containing catalyst. While not wishing to be bound by theory, the sulfidation step is believed to be necessary to achieve the surprisingly high alcohol / olefin conversion and mercaptan yield disclosed herein.

[0042] Optionally, the nickel-molybdenum catalyst may be dried or purged prior to step (i). Thus, the first and second methods for producing thiols may further include, prior to step (i), contacting the nickel-molybdenum catalyst with an inert gas at any suitable purging temperature, typically less than or equal to about 235°C. For example, the purging temperature may be in the same temperature range as the sulfidation temperatures disclosed herein, such as about 60°C to about 200°C, about 80°C to about 180°C, or about 110°C to about 160°C. In one specific aspect, the purging temperature may be the same as the initial sulfidation temperature, such that the nickel-molybdenum catalyst can be purged and then immediately sulfided, simply by changing the gas flow contacting the catalyst. In the purging step, any suitable inert gas may be used, such as helium, neon, argon, nitrogen, etc., and any combination thereof. Typically, nitrogen is used as the inert gas.

[0043] Referring now to step (ii), there are no particular limitations on the appropriate procedures for the contact (or reaction) in step (ii) of the first and second methods for producing thiols. For example, the step of contacting (or reacting) the alcohol (or olefin), H₂S, and the supported sulfur-containing catalyst may include contacting these components in any order to produce the desired thiols in acceptable yields. Typically, the alcohol (or olefin) and H₂S are first combined, and then the resulting reactant mixture is contacted with the supported sulfur-containing catalyst.

[0044] The first and second methods for producing thiols can be carried out at any suitable temperature for any suitable time. Representative and non-limiting ranges of temperature for step (ii) (or the formation of thiols) may include about 100°C to about 300°C, about 125°C to about 275°C, about 175°C to about 275°C, about 175°C to about 250°C, about 200°C to about 300°C, about 200°C to about 275°C, or about 200°C to about 250°C. These temperature ranges are also intended to cover cases where step (ii) (or the formation of thiols) is performed at a range of different temperatures falling within the respective temperature ranges, rather than at a single fixed temperature, wherein at least one temperature is within the enumerated range.

[0045] Similarly, there are no particular limitations on the time period for contact (or reaction) between alcohols (or olefins), H2S, and supported sulfur-containing catalysts, and any suitable time period may be observed. In some aspects, the time period may be at least about 1 minute, at least about 5 minutes, at least about 10 minutes, at least about 30 minutes, at least about 1 hour, at least about 2 hours, at least about 5 hours, or at least about 10 hours. In other aspects, the time period may be from about 30 seconds to about 48 hours, from about 1 minute to about 24 hours, from about 5 minutes to about 8 hours, from about 30 minutes to about 8 hours, or from about 1 hour to about 6 hours.

[0046] Typically, the first and second methods for forming thiols can be flow methods and / or continuous methods. In such cases, the alcohol (or olefin)-catalyst contact time (or reaction time) can be expressed as weight hourly space velocity (WHSV), which is the weight ratio (in g / g / hr) of alcohol (or olefin) in contact with a given weight of catalyst per unit time.

[0047] Although not limited thereto, the WHSV for methods of producing thiol compounds may have a minimum value of 0.01, 0.02, 0.05, 0.1, 0.25, or 0.5; or alternatively, a maximum value of 5, 4, 3, 2.5, 2, or 1. Typically, the WHSV can range from any minimum WHSV disclosed herein to any maximum WHSV disclosed herein. In one non-limiting aspect, the WHSV may be in the range of: about 0.01 to about 5; alternatively, about 0.01 to about 3; alternatively, about 0.01 to about 1; alternatively, about 0.02 to about 4; alternatively, about 0.02 to about 3; alternatively, about 0.05 to about 2; alternatively, about 0.05 to about 1.5; alternatively, about 0.1 to 4; alternatively, about 0.2 to about 3; alternatively, about 0.2 to about 1.2; alternatively, about 0.2 to about 1; alternatively, about 0.5 to about 4; alternatively, about 0.5 to about 2; or alternatively, about 0.5 to about 1. Other WHSV ranges are apparent from this disclosure. Any suitable reactor or vessel may be used to form thiols, and non-limiting examples of said reactor or vessel may include flow reactors, continuous reactors, packed tube reactors, and stirred tank reactors, including more than one reactor in series or parallel, and including any combination of reactor types and arrangements.

[0048] In some aspects of the invention, first and second methods for producing thiols may include contacting an alcohol (or olefin) compound and H2S with a fixed bed of supported sulfur-containing catalyst.

[0049] Not limited thereto, step (ii) and / or the formation of the thiol compound may be carried out at a reaction pressure in the range of about 50 to about 1000 psig (344 to 6890 kPag). Other representative and non-limiting ranges of reaction pressure may include about 50 to about 500 psig (344 to 3447 kPag), about 100 to about 800 psig (689 to 5515 kPag), about 150 to about 450 psig (1034 to 3103 kPag), about 200 to about 450 psig (1379 to 3103 kPag), about 200 to about 350 psig (1379 to 2413 kPag), or about 300 to about 450 psig (2068 to 3103 kPag).

[0050] There are no particular restrictions on the molar ratio of H2S to alcohol (or H2S to olefin), as long as H2S is used in excess. Typical molar ratio ranges for H2S to alcohol (or H2S to olefin) may include, but are not limited to, about 3:1 to about 50:1, about 3:1 to about 18:1, about 3:1 to about 10:1, about 4:1 to about 30:1, about 4:1 to about 20:1, about 5:1 to about 20:1, about 5:1 to about 15:1, about 10:1 to about 30:1, or about 10:1 to about 15:1.

[0051] The methods described herein result in unexpectedly high molar conversions of alcohols or olefins and / or unexpectedly high molar yields of thiols. On one hand, the minimum conversion (or yield) may be at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, or at least about 95%. On the other hand, the maximum conversion (or yield) may be about 97%, about 98%, about 99%, or about 99.5%, and may reach or approach 100% conversion of alcohols or olefins (or yield of thiols). Generally, the conversion (or yield) may range from any minimum conversion (or yield) disclosed herein to any maximum conversion (or yield) disclosed herein. Non-limiting ranges for conversion (or yield) may include about 50% to about 99.5%, about 70% to about 95%, about 80% to about 99%, about 90% to about 98%, or about 95% to 100%. For molar conversion, the percentage is based on the amount of alcohol (or olefin) reactant converted from the initial amount of alcohol (or olefin). Yield values ​​are also molar percentages and are based on the ratio of the number of moles of thiol produced to the number of moles of alcohol (or olefin). In some respects, these conversions (or yields) can be achieved using batch methods, while in others they can be achieved using flow or continuous methods, such as single-pass or multi-pass reactors (e.g., fixed-bed reactors).

[0052] Equally surprising is that the continuous flow method for producing thiols according to the present invention exhibits surprisingly high single-pass molar conversions (or single-pass molar yields) of olefins or alcohols. In one aspect, the minimum single-pass conversion (or yield) can be at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%. Additionally, the maximum single-pass conversion (or yield) can be about 90%, about 95%, about 98%, or about 99%, and can reach or approach 100% conversion of alcohols or olefins (or yields of thiols), depending on the reaction conditions. Generally, the single-pass conversion (or yield) can range from any minimum single-pass conversion (or yield) disclosed herein to any maximum single-pass conversion (or yield) disclosed herein. The non-limiting range of single-pass conversion rate (or yield) may include about 40% to about 90%, about 50% to about 95%, about 60% to about 98%, or about 70% to 100%.

[0053] The first and second methods for producing thiols disclosed herein typically produce a crude reaction mixture containing thiols, residual reactants, and relatively small amounts of byproducts (e.g., non-thiol reaction products such as heavy sulfides). Advantageously and unexpectedly, the amount of non-thiol reaction products (e.g., sulfides) in the reaction mixture is very low. For example, in one aspect, the reaction mixture may contain less than or equal to about 15 mol% of non-thiol reaction products, while in another aspect, the reaction mixture may contain less than or equal to about 10 mol% of non-thiol reaction products, and in yet another aspect, the reaction mixture may contain less than or equal to about 8 mol% (or 5 mol%, or 3 mol%) of non-thiol reaction products.

[0054] Advantageously, the selectivity for thiols in the first and second methods can be remarkably high, based on the total amount of thiols in the reaction mixture. For example, the selectivity for thiols can be at least about 75 mol% based on total thiols; alternatively, at least about 80 mol%; alternatively, at least about 85 mol%; alternatively, at least about 90 mol%; or alternatively, at least about 95 mol%.

[0055] In many cases, it may be necessary to separate thiol compounds from the reaction mixture for sale or for further industrial processes. Therefore, in some aspects, the first and second methods for producing thiol compounds may also include the step of separating the thiol compounds to form a product stream containing thiol compounds. The separation of thiol compounds can be achieved using any suitable technique to separate the thiol compounds from other components of the reaction mixture to form a product stream containing thiol compounds. Such techniques may include, but are not limited to, extraction, filtration, evaporation, or distillation, and combinations of two or more of these techniques. In a particular aspect of the invention, the separation step utilizes distillation at any suitable pressure (using one or more distillation columns). Advantageously, the low levels of non-thiols in the reaction mixture make the separation of, for example, thiol compounds by distillation a relatively simple process.

[0056] Additionally, other components of the reaction mixture (e.g., unreacted alcohols or olefins) may be recovered and recycled back to the reactor after step (ii). In such cases, the alcohols or olefins may be recycled until completely eliminated, such that all or substantially all (>99 mol%) of the alcohol or olefin reactants are converted into thiols or byproducts.

[0057] catalyst

[0058] Nickel-molybdenum catalysts and supported sulfur-containing catalysts may contain any suitable solid support, including any suitable solid oxide or similar material. Illustrative examples of solid supports may include silica, alumina (e.g., γ-alumina), magnesium oxide, boron oxide, titanium dioxide, zirconium oxide, zeolites, and mixed oxides thereof (e.g., silica-alumina). Combinations of more than one support material may be used in the catalyst.

[0059] If used, Y-zeolite (zeolite Y) and X-zeolite (zeolite X) can have approximately to approximately The average pore size within the range. The Si:Al ratio of X-zeolite is less than that of Y-zeolite. Typically, zeolite can be bonded to a carrier matrix (or binder), and non-limiting examples of the carrier matrix (or binder) may include silica, alumina, magnesium oxide, boron oxide, titanium dioxide, zirconium oxide, various clays, including mixed oxides thereof, and mixtures thereof.

[0060] The amount of nickel present in nickel-molybdenum catalysts and supported sulfur-containing catalysts is not particularly limited, but is generally in the range of about 1 to about 5% by weight. In one aspect, the amount of nickel may be about 1 to about 3% by weight, while in another aspect, the amount of nickel may be about 2 to about 5% by weight, and in yet another aspect, the amount of nickel may be about 2 to about 4% by weight, and in yet another aspect, the amount of nickel may be about 2.5 to about 4% by weight. These weight percentages are based on the amount of nickel relative to the total weight of the nickel-molybdenum catalyst or the supported sulfur-containing catalyst.

[0061] Similarly, there is no particular limitation on the amount of molybdenum on the catalyst, and it typically ranges from about 4 to about 18 wt%. In some respects, nickel-molybdenum catalysts and supported sulfur-containing catalysts may contain about 4 to about 16 wt% of the total weight of the respective catalyst; alternatively, about 10 to about 15 wt%; alternatively, about 11 to about 17 wt%; or alternatively, about 13 to about 16 wt% of molybdenum. While not wishing to be bound by theory, it is believed that higher molybdenum loading improves conversion and / or yield.

[0062] Typically, prior to use, nickel-molybdenum catalysts and supported sulfur-containing catalysts contain little or no carbon, for example, less than or equal to about 3% by weight. More commonly, the corresponding catalysts may contain less than or equal to about 2.5% by weight of carbon, less than or equal to about 2% by weight of carbon, less than or equal to about 1% by weight of carbon, or less than or equal to about 0.5% by weight of carbon. As mentioned above, these weight percentages are based on the total weight of the corresponding nickel-molybdenum catalyst or supported sulfur-containing catalyst.

[0063] While nickel-molybdenum catalysts are essentially sulfur-free before sulfidation, supported sulfur-containing catalysts (after sulfidation) typically contain at least about 3% by weight of sulfur and less than or equal to about 18% by weight of sulfur. Illustrative and non-limiting ranges for the amount of sulfur on supported sulfur-containing catalysts include about 4% to about 17% by weight, about 5% to about 15% by weight, about 7% to about 13% by weight, etc. These weight percentages are based on the total weight of the supported sulfur-containing catalyst. While not wishing to be bound by theory, it is believed that appropriate levels of sulfur are necessary to achieve the surprisingly high alcohol / olefin conversions and thiol yields disclosed herein.

[0064] Nickel-molybdenum catalysts and supported sulfur-containing catalysts can have any suitable BET surface area, ranging from about 75 to about 400 m². 2 / g, approximately 100 to approximately 350m 2 / g, approximately 100 to approximately 300m 2 / g, approximately 125 to approximately 275m 2 / g, approximately 150 to approximately 375m 2 / g, or approximately 150 to approximately 250 mg 2 / g of surface area.

[0065] Nickel-molybdenum catalysts and supported sulfur-containing catalysts can have any suitable shape or form, depending on the type of process used to convert alcohols or olefins into thiols (e.g., fixed-bed vs. fluidized-bed). Illustrative and non-limiting shapes and forms include powders, spherical or round (e.g., spheres), elliptical, pellets, beads, cylinders, particles (e.g., regular and / or irregular), trilobes, quadrilobes, rings, wagon wheels, monoliths, etc., and any combination thereof. Therefore, various methods can be used to prepare supported catalyst particles, including, for example, extrusion, spray drying, granulation, marumerizing, spheroidization, agglomeration, droplets, etc., and combinations thereof.

[0066] In some respects, nickel-molybdenum catalysts and supported sulfur-containing catalysts may be in the form of pellets or beads, with an average particle size (or average diameter) ranging from about 0.5 to about 15 mm, about 1 to about 7 mm, or about 2.5 to about 5 mm. As mentioned above, the size of nickel-molybdenum catalyst and supported sulfur-containing catalyst particles can be varied to suit specific methods for converting alcohols or olefins into thiols.

[0067] Example

[0068] The present invention is further illustrated by the following embodiments, which should not be construed as limiting the scope of the invention in any way. Various other aspects, modifications, and equivalents will arise in those skilled in the art upon reading this description without departing from the spirit of the invention or the scope of the appended claims.

[0069] These examples demonstrate that the sulfur-containing nickel-molybdenum catalyst used herein provides better activity and selectivity for the production of thiols from H2S and olefins or alcohols compared to the use of cobalt-molybdenum catalysts. Furthermore, the increase in conversion and thiolate yield (e.g., an increase of 5-10%) was achieved under significantly less demanding operating conditions (i.e., lower reaction temperatures, higher hydrocarbon space velocities, and lower H2S:olefin or H2S:alcohol feed ratios).

[0070] Examples 1-2

[0071] In Examples 1-2, methanethiol (MeSH) was synthesized from methanol (MeOH) and H₂S. Each mole of methanol in the reaction produces one mole of water. Methanol can further react (e.g., with MeSH) to form dimethyl sulfide (DMS) and water. Higher temperatures generally favor the production of DMS compared to MeSH. Here, MeSH is the desired product. Additionally, methanol (and MeSH) can decompose to form CO₂ (and CS₂) and hydrogen, and higher temperatures increase the rate of these unwanted decomposition reactions.

[0072] Examples 1-2 use a 1-inch stainless steel reactor in a downflow process and are filtered through a 14-20 mesh screen. Dilute the catalyst to help establish isothermal reactor operation. Temperature measurements are taken using a 1 / 4-inch center-wire thermocouple sheath with three thermocouples, and the reaction temperature (Temp) is the arithmetic mean of the three temperatures (note that the temperatures of the three thermocouples are typically within 2°C of each other).

[0073] The reaction mixture was analyzed using an online HP-6580 gas chromatograph equipped with a thermal conductivity detector. The temperature profile was obtained by holding at 35°C for 5 min, then ramping to 70°C at a rate of 5°C / min, followed by ramping to 260°C at a rate of 15°C / min and holding for 10 min. The chromatographic column was a CP-Sil 5CB for sulfur, 30 m × 320 μm × 4 μm, with a He flow rate of 0.5 mL / min. The detector was operated at 200°C, and the response factors for this detector were: CO2 0.92; H2S 0.88; H2O 0.55; dimethyl ether (DME) 0.67; MeOH 0.58; MeSH 0.81; CS2 0.82; DMS 0.80; and dimethyl disulfide (DMDS) 0.80.

[0074] For Example 1, Table 1 summarizes the experimental results for the synthesis of methanethiol from methanol and H2S using a cobalt molybdate catalyst (CoMo, 3 wt% Co and 11 wt% Mo, fresh catalyst basis) at a feed ratio of 7.6:1 H2S:methanol, while Table 2 summarizes the results at a feed ratio of 10.8:1 H2S:methanol, and Table 3 summarizes the results at a feed ratio of 15.5:1 H2S:methanol. MeSH yield was defined as the product of methanol conversion and methanethiol selectivity.

[0075] The results of Example 1 indicate that a minimum temperature of at least 240 °C is required for 99 mol% methanol conversion using a cobalt molybdate catalyst, but the maximum MeSH yield (product of conversion and selectivity) occurs between 220 and 230 °C. At any temperature equal to or below 240 °C, no 99 mol% methanol conversion level was achieved at a feed ratio of 7.6:1, and 100% methanol conversion was not observed at any temperature equal to or below 240 °C. A higher feed molar ratio of 15.5:1 resulted in higher selectivity for MeSH than at a feed ratio of 10.8:1, which in turn yielded a higher MeSH yield than at a feed ratio of 7.6:1.

[0076] The highest yield of methanethiol obtained was 89-90 mol% (15.5:1 feed ratio and 220 °C), although the methanol conversion was less than 99 mol% under these conditions. The highest yield of methanethiol obtained was 88.8 mol% (15.5:1 feed ratio and 240 °C) while achieving at least 99% methanol conversion.

[0077] For Example 2, Table 4 summarizes the experimental results for the synthesis of methanethiol from methanol and H2S using a nickel molybdate catalyst (NiMo, 3 wt% Ni and 10-11 wt% Mo, fresh catalyst basis) at a feed ratio of 9.9:1 H2S:methanol, while Table 5 summarizes the results at a feed ratio of 14.8:1 H2S:methanol, and Table 6 summarizes the results at a feed ratio of 17.1:1 H2S:methanol. MeSH yield was defined as the product of methanol conversion and methanethiol selectivity.

[0078] The results of Example 2 show that the NiMo catalyst of Example 2 achieved substantially complete (>99 mol%) methanol conversion at 220 °C (or higher), compared to the 240 °C required when using the CoMo catalyst of Example 1. Furthermore, the 100 mol% methanol conversion in Example 2 was achieved at 230 °C or higher (feed ratio greater than 14:1), compared to the CoMo catalyst of Example 1, which did not show 100 mol% methanol conversion at any temperature. Similar to Example 1, the higher H2S / methanol feed ratio resulted in increased MeSH selectivity in Example 2. However, the NiMo catalyst of Example 2 yielded a MeSH yield of 91.8 mol% (at a methanol conversion of >99 mol%), which was not achieved using the CoMo catalyst of Example 1 (MeSH yield of 88.8 mol% at a methanol conversion of >99 mol%).

[0079] Furthermore, operation at or near 100% methanol conversion (as in Example 2 using a NiMo catalyst) is ideal because it eliminates the need for downstream separation or purification to remove or recycle unreacted methanol. Methanol is difficult to remove from the product MeSH because it does not form a low-boiling azeotrope with water. Typically, the methanol concentration in commercial MeSH products must be below 400 ppmw.

[0080] Examples 3-4

[0081] In Examples 3-4, isopropyl mercaptan (IPM, 2-propanethiol) was synthesized from propylene and H2S. Examples 3-4 were conducted and analyzed in a manner similar to Examples 1-2, except that a jacketed 6-inch inner diameter 5% chromium steel reactor was used in a downflow process, and the inlet feed and outlet reaction mixture temperatures were measured by thermocouples, with the reaction temperature (Temp) being the arithmetic mean of the inlet and outlet temperatures.

[0082] The reaction mixture was analyzed using an Agilent 6850A gas chromatograph equipped with an Agilent G2613A liquid autosampler. The GC was equipped with a thermal conductivity detector operating at 300 °C. The temperature profile was as follows: 50 °C held for 1.5 min, then ramped to 100 °C at 20 °C / min, then ramped to 275 °C at 50 °C / min and held for 1.5 min. A DB-1 (standard polysiloxane) column, 15 m × 320 μm × 1 μm, was used, with an H2 flow rate of 0.8 mL / min, operated in ramp flow mode.

[0083] For Example 3, Table 7 summarizes the experimental results for the synthesis of IPM from propylene and H2S using a cobalt molybdate catalyst (CoMo, 3 wt% Co and 10-11 wt% Mo, based on fresh catalyst) at a H2S:propylene molar feed ratio of 9:1-11:1, a reaction pressure of 330 psig, and a feed rate based on 0.6-0.7 WHSV of propylene. Table 7 shows the composition of the reaction mixture as a function of temperature, where isopropyl mercaptan (IPM), n-propyl mercaptan (NPM), and unwanted heavy products (sulfides, such as di-n-propyl sulfide or isopropyl-n-propyl sulfide) are the major products.

[0084] As shown in Table 7, the highest yield of IPM in the reactor effluent was 78.4 mol% when using the CoMo catalyst, while the typical yield was a few percentage points lower. The highest combined yield of IPM and NPM was 87.4 mol%. Achieving these results required reactor temperatures of approximately 400℉ and higher. Under these conditions, the average amount of sulfides was 10.6 mol%, and unreacted propylene ranged from 0.4 to 1.2 mol%.

[0085] For Example 4, Table 8 summarizes the experimental results for the synthesis of IPM from propylene and H2S using a nickel molybdate catalyst (NiMo, 3.4 wt% Ni and 14 wt% Mo, based on fresh catalyst) at a molar feed ratio of 8.8:1 H2S:propylene, a reaction pressure of 330 psig, and a feed rate based on propylene of 0.73 WHSV. Table 8 shows the composition of the reaction mixture as a function of temperature, where isopropyl mercaptan (IPM), n-propyl mercaptan (NPM), and unwanted heavy products (sulfides, such as di-n-propyl sulfide or isopropyl-n-propyl sulfide) are the major products.

[0086] For Example 4, Table 9 also summarizes the experimental results for the synthesis of IPM from propylene and H2S using a nickel molybdate catalyst (NiMo, 3.4 wt% Ni and 14 wt% Mo, based on fresh catalyst) at a H2S:propylene molar feed ratio of 6:1–8:1, a reaction pressure of 330 psig, and a feed rate based on 0.8–0.9 WHSV of propylene. Table 9 shows the composition of the reaction mixture as a function of temperature, where isopropyl mercaptan (IPM), n-propyl mercaptan (NPM), and unwanted heavy products (sulfides, such as di-n-propyl sulfide or isopropyl-n-propyl sulfide) are the major products.

[0087] As shown in Tables 8-9, the highest yield of IPM in the reactor effluent using the NiMo catalyst was 88.2 mol%, while the typical yield was above 85 mol%. The highest combined yield of IPM and NPM was 96.2 mol%. To achieve these results, the reactor temperature used was only about 365-380℉. Under these conditions, the average amount of sulfides was less than 5 mol%, and the unreacted propylene was in the range of 0.1 mol% or less.

[0088] Comparing Examples 3 (CoMo) and 4 (NiMo), the highest IPM yield (88.2 mol%) in Example 4 was 9.8 mol% higher than the highest IPM yield in Example 3, and this was achieved in Example 4 using a NiMo catalyst at a temperature 30°F lower. Furthermore, the amount of unreacted propylene in the reactor mixture of Example 4 was 0.1 mol% or less, while the nickel molybdate catalyst in Example 4 operated at a space velocity up to 20% higher and a temperature up to 27°F lower than the cobalt molybdate catalyst in Example 3.

[0089] The amount of unwanted sulfides is consistently lower when using NiMo catalysts (up to 7.4%), compared to at least 8.8% when using CoMo catalysts. The lower reactor temperature required to increase IPM yield allows for a reduction of approximately half in sulfide formation when using NiMo catalysts. This combination of higher product yields and higher propylene conversion at lower reaction temperatures compared to using CoMo catalysts represents a significant and unexpected advantage for the synthesis of isopropanethiol using NiMo catalysts.

[0090] Examples 5-6

[0091] In Examples 5-6, sec-butylthiol (SBM, 2-butanethiol) was synthesized from 1-butene and H₂S. Examples 5-6 were performed and analyzed in the same manner as Examples 3-4. The reaction mixture was analyzed using an Agilent 6850A gas chromatograph equipped with an Agilent G2613A liquid autosampler. The GC was equipped with a flame ionization detector operating at 300 °C. The temperature profile was obtained by holding at 35 °C for 1.8 min, then increasing to 250 °C at a rate of 30 °C / min and holding for 2 min. The chromatographic column was a DB-1 (standard polysiloxane), 30 m × 320 μm × 0.25 μm, with an H₂ flow rate of 1.5 mL / min, operated in ramp pressure mode.

[0092] For Examples 5-6, Table 10 summarizes the experimental results for the synthesis of SBM from 1-butene and H₂S using a cobalt molybdate catalyst (CoMo, 3 wt% Co and 10 wt% Mo, based on fresh catalyst, Examples 5A and 5B) and a nickel molybdate catalyst (NiMo, 3.4 wt% Ni and 14 wt% Mo, based on fresh catalyst, Example 6). Table 10 shows the composition of the reaction mixture and the reaction temperature, where sec-butanethiol (SBM), n-butanethiol (NBM), and unwanted heavy products (sulfides, such as di-n-butyl sulfide, di-sec-butyl sulfide, and sec-n-butyl sulfide) are the major products. WHSV values ​​are based on 1-butene.

[0093] Using the CoMo catalysts in Examples 5A and 5B, the highest SBM yield in the reaction mixture was 73.7 wt%, the average SBM yield was 71.5 wt%, and the thiol yield was 81.5 wt%. The reaction temperature was 404℉, producing 8-12 wt% sulfides and over 6 wt% unreacted 1-butene. In Example 6, using a NiMo catalyst, the SBM yield in the reaction mixture was surprisingly 10 wt% higher than the average yield in Example 5, and this was achieved at a lower temperature of 33℉. Sulfides were reduced by 2-5 wt% and unreacted butene by 1 wt%, while using a high space velocity of 15% and a low H2S:butene feed ratio of 32%.

[0094] Example 7

[0095] Example 7 summarizes the pre-sulfurization or sulfidation of the base catalyst using H2S. Due to product purity issues in the synthesis and manufacture of mercaptans, and further, the lack of available H2S at pressures greater than approximately 30 psig in most refineries, diesel hydrocarbons cannot be used to sulfidate catalysts used for mercaptan synthesis. The base NiMo catalysts used in Examples 3-6 were sulfided using H2S at pressures above 100 psig. The use of high-pressure H2S mitigates the temperature rise during the exothermic catalytic sulfidation reaction (e.g., MoO2 + 2H2S → MoS2 + 2H2O). Isothermal conditions are typically required during sulfidation to maximize catalyst activity and effectiveness.

[0096] Prior to sulfidation, the base NiMo catalyst was purged in nitrogen at 120–150 °C for approximately 10 hours, followed by pre-sulfidation with an H₂S gas stream at a pressure equal to or greater than 100 psig (but less than 250 psig) for less than 24 hours, producing approximately 10–11% by weight of sulfur on the sulfidation catalyst. Time and temperature data during typical pre-sulfidation experiments are listed in Table 11. The highest temperature recorded during sulfidation was 283 °F, although the highest weight-averaged sulfidation temperature was 184 °F. At this temperature peak, the reactor preheating was reduced by two hours to help mitigate the temperature rise. After the temperature in the reactor began to rise, the H₂S feed rate was also reduced for several hours to help slow the temperature rise in the reactor.

[0097] Examples 8-9

[0098] In Examples 8-9, ethyl mercaptan / ethanethiol was synthesized from ethylene and H₂S. Examples 8-9 were performed and analyzed in the same manner as Examples 5-6, except that a jacketed tubular reactor with 2-inch stainless steel tubing was used in a downflow process, and the temperatures of the inlet feed and effluent reaction mixtures were measured by thermocouples, where the reaction temperature (Temp) was the arithmetic mean of the inlet and outlet temperatures. The effluent reaction mixture was analyzed using an online gas chromatograph equipped with a flame ionization detector. The key components of the effluent reaction mixture were the desired product, ethyl mercaptan / ethanethiol, and unwanted heavy sulfide compounds, including diethyl sulfide and diethyl disulfide.

[0099] For Examples 8-9, Table 12 summarizes the experimental results for the synthesis of ethanethiol from ethylene and H₂S using a cobalt molybdate catalyst (CoMo, 3 wt% Co and 11 wt% Mo, based on fresh catalyst, Example 8) and a nickel molybdate catalyst (NiMo, 3.4 wt% Ni and 14 wt% Mo, based on fresh catalyst, Example 9). Sulfidation was carried out as described in Example 7. Table 12 shows the composition of the reaction mixture and the reaction temperature, where ethanethiol and unwanted heavy products (sulfides, such as diethyl sulfide and diethyl disulfide) are the major products. WHSV values ​​are based on ethylene, and the H₂S:ethylene molar ratio is 5.1-5.2:1.

[0100] As can be seen from Table 12, the maximum achievable ethanethiol concentration in the reactor effluent is 5.6% by weight higher when using the NiMo catalyst (Example 9) compared to using the CoMo catalyst (Example 8). Under the same reactor pressure, ethylene space velocity, and H2S:ethylene ratio, the reaction temperature is 43°C lower when using the NiMo catalyst compared to the CoMo catalyst, while achieving the maximum ethanethiol conversion (99.9% by weight) across the reactor outlet.

[0101] This lower reaction temperature is a significant operational advantage because it reduces the required reactor preheating and preheating supply temperature. Furthermore, the lower operating temperature results in a 44% reduction in the yield of unwanted sulfides and disulfides. This reduction in sulfides and disulfides has not been achieved under any reactor conditions using a CoMo catalyst while converting more than 90% by weight of ethylene in a single pass.

[0102] Advantageously, the NiMo catalyst used in Example 9 provided a significant increase in catalyst activity and yield. Regarding activity, the excellent NiMo catalyst activity resulted in an ethylene conversion greater than 99.9% by weight under the same reactor operating conditions, at a temperature 43°C lower than that of the CoMo catalyst (whose highest ethylene conversion was only 96.5% by weight). Regarding yield, Example 9 using the NiMo catalyst achieved a 97.1% by weight yield of ethanethiol, which was also unexpectedly higher than the yield achieved using the CoMo catalyst in Example 8.

[0103]

[0104]

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113]

[0114] The invention has been described above with reference to various aspects and specific embodiments. Many variations will occur to those skilled in the art based on the foregoing specific embodiments. All such obvious variations are within the full scope of the appended claims. Other aspects of the invention may include, but are not limited to, the following (aspects are described as "comprising / including…", but alternatively, may be "consistent with…" or "consisting with…"):

[0115] Aspect 1. A method for producing a thiol compound, the method comprising:

[0116] (i) To form a supported sulfur-containing catalyst by contacting a nickel-molybdenum catalyst with H2S at a sulfidation temperature of less than or equal to about 235 °C; and

[0117] (ii) Contact the alcohol compound, H2S and the supported sulfur-containing catalyst to form a reaction mixture containing the thiol compound.

[0118] Aspect 2. A method for producing a thiol compound, the method comprising:

[0119] (i) To form a supported sulfur-containing catalyst by contacting a nickel-molybdenum catalyst with H2S at a sulfidation temperature of less than or equal to about 235 °C; and

[0120] (ii) Contact the olefin compound, H2S and the supported sulfur-containing catalyst to form a reaction mixture containing the thiol compound.

[0121] Aspect 3. As defined in Aspect 1, where:

[0122] The thiol compound has the formula (A): R 1 –SH;

[0123] The alcohol compound has the formula (B): R 1 -OH; and

[0124] R 1 C1 to C 18Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl.

[0125] Aspect 4. As defined in Aspect 2, where:

[0126] The thiol compound has the formula (C): R 2 –SH;

[0127] The olefin compound has the formula C=C or formula (D): R 1 –C=C;

[0128] R 1 C1 to C 18 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl; and

[0129] R 2 C3 to C 20 Substituted or unsubstituted cycloalkyl or straight-chain or branched alkyl.

[0130] Aspect 5. The method as defined in any of the preceding aspects, the method further comprising, prior to step (i), contacting the nickel-molybdenum catalyst with an inert gas at a purging temperature of less than or equal to about 235°C.

[0131] Aspect 6. The method as defined in Aspect 5, wherein the inert gas includes any suitable inert gas or any inert gas disclosed herein, such as helium, neon, argon, nitrogen, etc., or any combination thereof.

[0132] Aspect 7. The method as defined in aspect 5 or 6, wherein the purge temperature is any suitable purge temperature or any temperature within the range disclosed herein, such as about 60°C to about 200°C, about 110°C to about 160°C, etc.

[0133] Aspect 8. The method as defined in any of the preceding aspects, wherein the vulcanization temperature is any suitable vulcanization temperature or any temperature within the range disclosed herein, such as about 60°C to about 200°C, about 40°C to about 100°C, about 110°C to about 160°C, etc.

[0134] Aspect 9. The method as defined in any of the preceding aspects, wherein step (i) comprises contacting the nickel-molybdenum catalyst with inlet H2S at an inlet sulfidation temperature of about 10°C to about 90°C, about 35°C to about 70°C, etc.

[0135] Aspect 10. The method as defined in any of the preceding aspects, wherein step (i) is carried out under any suitable vulcanization pressure or pressure within any range disclosed herein, such as about 50 to about 250 psig, about 100 to about 150 psig, etc.

[0136] Aspect 11. The method as defined in any of the preceding aspects, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst contain any suitable amount of nickel or any amount within any range disclosed herein, such as about 1 to about 5 wt%, about 1 to about 3 wt%, about 2 to about 5 wt%, about 2 to about 4 wt%, about 2.5 to about 4 wt% of nickel, etc., based on the total weight of the respective catalyst.

[0137] Aspect 12. The method as defined in any of the preceding aspects, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst contain any suitable amount of molybdenum or any amount within any range disclosed herein, such as about 4 to about 18 wt%, about 4 to about 16 wt%, about 10 to about 15 wt%, about 11 to about 17 wt%, about 13 to about 16 wt% of molybdenum, etc., based on the total weight of the respective catalyst.

[0138] Aspect 13. The method as defined in any of the preceding aspects, wherein the supported sulfur-containing catalyst contains any suitable amount of sulfur or an amount within any range disclosed herein, such as about 3 to about 18 wt%, about 4 to about 17 wt%, about 5 to about 15 wt%, about 7 to about 13 wt% of sulfur, etc., based on the total weight of the catalyst.

[0139] Aspect 14. The method as defined in any of the preceding aspects, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst contain any suitable amount of carbon or an amount within any range disclosed herein, such as less than or equal to about 3 wt%, less than or equal to about 2.5 wt%, less than or equal to about 2 wt%, less than or equal to about 1 wt%, less than or equal to about 0.5 wt% of carbon, etc., based on the total weight of the respective catalyst.

[0140] Aspect 15. The method as defined in any of the preceding aspects, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst comprise a solid support, said solid support comprising any suitable solid support or any solid support disclosed herein, such as silica, alumina (e.g., γ-alumina), magnesium oxide, boron oxide, titanium dioxide, zirconium oxide, zeolite, etc., or mixed oxides thereof, or mixtures thereof.

[0141] Aspect 16. The method as defined in any of the preceding aspects, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst are characterized by any suitable BET surface area or any BET surface area disclosed herein, for example, about 100 to about 300 m². 2 / g, approximately 125 to approximately 275m 2 / g, approximately 150 to approximately 250m 2 / g etc.

[0142] Aspect 17. The method as defined in any of the preceding aspects, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst are any suitable shape or form or any shape or form disclosed herein, such as powder, round or spherical (e.g., spheres), elliptical, pellet, bead, cylinder, particle (e.g., regular and / or irregular), trefoil, tetralobite, ring, wheel-shaped, monolithic, etc., or any combination thereof.

[0143] Aspect 18. The method as defined in any of the preceding aspects, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst are characterized by any suitable average particle size (or average diameter) or any average particle size (or average diameter) disclosed herein, for example, about 0.5 to about 15 mm, about 1 to about 7 mm, about 2.5 to about 5 mm, etc.

[0144] Aspect 19. The method as defined in any of Aspects 3-18, where R 1 and R 2 It is a branched alkyl group.

[0145] Aspect 20. The method as defined in any of Aspects 3-18, where R 1 and R 2 It is a straight-chain alkyl group.

[0146] Aspect 21. The method as defined in any of Aspects 3-20, where R 1 and R 2 It is a substituted alkyl group (e.g., a phenyl-substituted alkyl group).

[0147] Aspect 22. The method as defined in any of Aspects 3-21, where R 1 C1 to C 12 alkyl.

[0148] Aspect 23. The method as defined in any of Aspects 3-18, where R 1 It can be methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, cyclopentyl, or cyclohexyl.

[0149] Aspect 24. The method as defined in any of Aspects 3-18, where R 1 It can be methyl, ethyl, propyl, or butyl.

[0150] Aspect 25. The method as defined in any of Aspects 3-18, where R 1 It can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, or tert-pentyl.

[0151] Aspect 26. The method as defined in any of Aspects 1-18, wherein the thiol compound is methanethiol, ethanethiol, isopropanethiol or sec-butanethiol.

[0152] Aspect 27. The method as defined in any of the preceding aspects, wherein the method comprises combining an alcohol compound (or olefin compound) with H2S prior to contacting a supported sulfur-containing catalyst.

[0153] Aspect 28. The method as defined in any of the preceding aspects, wherein step (ii) is carried out at a temperature within any suitable range or any range disclosed herein, such as about 100°C to about 300°C, about 175°C to about 275°C, about 200°C to about 250°C, etc.

[0154] Aspect 29. The method as defined in any of the preceding aspects, wherein step (ii) is performed under pressure within any suitable range or within any range disclosed herein, such as about 50 to about 1000 psig, about 100 to about 800 psig, about 150 to about 450 psig, etc.

[0155] Aspect 30. The method as defined in any of the preceding aspects, wherein the molar ratio of H2S: alcohol (or H2S: olefin) is in any suitable range or in any range disclosed herein, such as about 3:1 to about 10:1, about 4:1 to about 30:1, about 5:1 to about 20:1, about 10:1 to about 15:1, etc.

[0156] Aspect 31. The method as defined in any of the preceding aspects, wherein the method comprises contacting an alcohol compound (or olefin compound) and H2S with a fixed bed of supported sulfur-containing catalyst.

[0157] Aspect 32. The method as defined in any of the preceding aspects, wherein step (ii) is performed under any suitable WHSV or any WHSV within the scope disclosed herein, such as about 0.01 to about 3, about 0.05 to about 1.5, about 0.2 to about 1, etc.

[0158] Aspect 33. The method as defined in any of the preceding aspects, wherein the conversion (or yield) of the alcohol or olefin compound is any molar percentage conversion (or molar yield) disclosed herein, such as at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, etc.

[0159] Aspect 34. The method as defined in any of the preceding aspects, wherein the single-pass conversion (or single-pass yield) of the alcohol or olefin compound is any single-pass molar percentage conversion (or single-pass molar yield) disclosed herein, such as at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, etc.

[0160] Aspect 35. The method as defined in any of the preceding aspects, wherein the reaction mixture contains less than or equal to about 15 mol% of non-thiol reaction products (e.g., sulfides), less than or equal to about 10 mol% of non-thiol reaction products, less than or equal to about 5 mol% of non-thiol reaction products, etc.

[0161] Aspect 36. The method as defined in any of the preceding aspects, wherein the selectivity of the thiol compound is any selectivity disclosed herein, such as at least about 75 mol%, at least about 80 mol%, at least about 85 mol%, at least about 90 mol%, at least about 95 mol%, etc., based on the total thiol compounds in the reaction mixture.

[0162] Aspect 37. The method as defined in any of the preceding aspects, further comprising the step of separating thiol compounds from the reaction mixture to form a product stream containing thiol compounds using any suitable technique or any technique disclosed herein, such as extraction, filtration, evaporation, distillation, etc., or any combination thereof.

[0163] Aspect 38. The method as defined in any of the preceding aspects, wherein the unreacted alcohol (or unreacted olefin) is recycled after step (ii).

Claims

1. A method for producing a thiol compound, the method comprising: (i) To form a supported sulfur-containing catalyst by contacting the nickel-molybdenum catalyst with H2S at a sulfidation temperature of less than or equal to 235 °C; as well as (ii) The alcohol compound, H2S, and the supported sulfur-containing catalyst are contacted at a temperature in the range of 100°C to 300°C to form a reaction mixture containing the thiol compound. Step (i) includes contacting the nickel-molybdenum catalyst with inlet H2S at an inlet sulfidation temperature of 10°C to 90°C; The thiol compound is ethanethiol, isopropanethiol, or sec-butanethiol; and The nickel-molybdenum catalyst and the supported sulfur-containing catalyst are independently at 100 to 300 m 2 The BET surface area per g is characterized.

2. A method for producing a thiol compound, the method comprising: (i) To form a supported sulfur-containing catalyst by contacting the nickel-molybdenum catalyst with H2S at a sulfidation temperature of less than or equal to 235 °C; as well as (ii) Contacting the olefin compound, H2S, and the supported sulfur-containing catalyst at a temperature in the range of 100°C to 300°C to form a reaction mixture containing the thiol compound. Step (i) includes contacting the nickel-molybdenum catalyst with inlet H2S at an inlet sulfidation temperature of 10°C to 90°C; The thiol compound is ethanethiol, isopropanethiol, or sec-butanethiol; and The nickel-molybdenum catalyst and the supported sulfur-containing catalyst are independently at 100 to 300 m 2 The BET surface area per g is characterized.

3. The method of claim 1, wherein the alcohol compound comprises ethanol, propanol, butanol, or any combination thereof.

4. The method of claim 2, wherein the olefin compound comprises ethylene, propylene, butene, or any combination thereof.

5. The method of claim 1 or 2, wherein step (i) is performed under the following conditions: Vulcanization temperatures of 60°C to 235°C, 60°C to 200°C, 40°C to 100°C, 80°C to 225°C, 80°C to 180°C, 110°C to 235°C, 110°C to 200°C, or 110°C to 160°C; and Vulcanization pressures of 50 to 250 psig, 50 to 200 psig, 100 to 250 psig, 100 to 200 psig, or 100 to 150 psig.

6. The method of claim 1 or 2, wherein step (i) comprises contacting the nickel-molybdenum catalyst with inlet H2S at an inlet sulfidation temperature of 20°C to 80°C, 20°C to 60°C, or 35°C to 70°C.

7. The method of claim 1 or 2, wherein step (ii) is performed under the following conditions: Temperatures within the range of 125°C to 275°C, 175°C to 275°C, 175°C to 250°C, 200°C to 300°C, 200°C to 275°C, or 200°C to 250°C; Pressures ranging from 50 to 1000 psig, 50 to 500 psig, 100 to 800 psig, 150 to 450 psig, 200 to 450 psig, 200 to 350 psig, or 300 to 450 psig; and WHSV in the range of 0.01 to 5, 0.02 to 3, 0.05 to 1.5, 0.1 to 4, 0.2 to 3, 0.2 to 1.2, 0.2 to 1, 0.5 to 2, or 0.5 to 1.

8. The method of claim 1 or 2, wherein step (ii) comprises contacting the alcohol compound or the olefin compound and H2S with the fixed bed of the supported sulfur-containing catalyst.

9. The method of claim 1 or 2, wherein the molar ratio of H2S: alcohol compound or H2S: olefin compound is in the range of 3:1 to 50:1, 3:1 to 18:1, 3:1 to 10:1, 4:1 to 30:1, 4:1 to 20:1, 5:1 to 20:1, 5:1 to 15:1, 10:1 to 30:1, or 10:1 to 15:

1.

10. The method of claim 1 or 2, further comprising the step of contacting the nickel-molybdenum catalyst with an inert gas at a purging temperature of less than or equal to 235°C prior to step (i).

11. The method of claim 10, wherein: The inert gas includes nitrogen; and The purging temperature is 60°C to 200°C, 80°C to 180°C, or 110°C to 160°C.

12. The method as claimed in claim 1 or 2, wherein: The yield of the thiol compound is at least 50 mol%, at least 70 mol%, at least 80 mol%, at least 90 mol%, 80 to 99 mol%, or 90 to 98 mol%; and / or The conversion rate of the alcohol or olefin compound is at least 50 mol%, at least 80 mol%, at least 90 mol%, at least 95 mol%, 80 to 99 mol%, 90 to 98 mol%, or 95 to 100 mol%.

13. The method of claim 1 or 2, wherein the reaction mixture contains less than or equal to 10 mol%, less than or equal to 8 mol%, less than or equal to 5 mol%, or less than or equal to 3 mol% of non-thiol reaction products.

14. The method of claim 1 or 2, wherein the selectivity of the thiol compound is at least 75 mol%, at least 80 mol%, at least 85 mol%, at least 90 mol%, or at least 95 mol% based on the total thiol compounds in the reaction mixture.

15. The method of claim 1 or 2, further comprising the step of separating the thiol compound from the reaction mixture to form a product stream containing the thiol compound.

16. The method of claim 1 or 2, wherein the unreacted alcohol or olefin compound is recycled after step (ii).

17. The method of claim 1 or 2, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst independently comprise: solid carrier; 1 to 5% by weight, 1 to 3% by weight, 2 to 5% by weight, 2 to 4% by weight, or 2.5 to 4% by weight of nickel; and 4 to 18 wt%, 4 to 16 wt%, 10 to 15 wt%, 11 to 17 wt%, or 13 to 16 wt% of molybdenum.

18. The method of claim 1 or 2, wherein the nickel-molybdenum catalyst and the supported sulfur-containing catalyst independently contain less than or equal to 3% by weight, less than or equal to 2.5% by weight, less than or equal to 2% by weight, less than or equal to 1% by weight, or less than or equal to 0.5% by weight of carbon.

19. The method of claim 1 or 2, wherein the BET surface area is 125 to 275 m². 2 / g, 150 to 375 m 2 / g, or 150 to 250 m 2 / g.

20. The method of claim 1 or 2, wherein the supported sulfur-containing catalyst contains 3 to 18% by weight, 4 to 17% by weight, 5 to 15% by weight, or 7 to 13% by weight of sulfur.

21. The method of claim 17, wherein the solid support comprises silicon dioxide, aluminum oxide, magnesium oxide, boron oxide, titanium dioxide, zirconium oxide, zeolite, mixed oxides thereof, or mixtures thereof.

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