Methods for preparing vicinal diols

Abstract

This invention discloses a method for preparing vicinal diols. The method includes reacting an olefin, an oxidant, and a substituted benzenesulfonic acid solution in the presence of a catalyst containing a titanium-silicon molecular sieve to obtain a product containing vicinal diols. This method has the advantages of mild reaction conditions, simple operation, high raw material conversion rate, high selectivity for vicinal diols, and high effective utilization rate of hydrogen peroxide.

Description

Technical Field

[0001] This invention relates to a method for preparing vicinal diols by olefin oxidation, and more particularly to a method for preparing vicinal diols by olefin oxidation in the presence of a titanium-silicon molecular sieve catalyst. Background Technology

[0002] vicinal glycols are hydrocarbon organic compounds in which hydroxyl groups are present on two adjacent carbon atoms. Common vicinal glycols include 1,2-ethylene glycol (hereinafter referred to as ethylene glycol), 1,2-propanediol (hereinafter referred to as propylene glycol), 1,2-butanediol (hereinafter referred to as butanediol), and 1,2-hexanediol (hereinafter referred to as hexanediol). Vicinal glycols have important applications. For example, ethylene glycol can be used as a solvent, antifreeze, and in the synthesis of polyester; propylene glycol can be used to synthesize unsaturated polyester resins and as an antifreeze and moisturizer; and hexanediol can be used in the production of high-end cosmetics. Vicinal glycols have broad market applications and large production volumes. For example, in 2018, the global production capacity of propylene glycol reached 1.8 million tons per year.

[0003] The main production method for vicinal glycols involves the hydrolysis of upstream epoxides under specific conditions. For example, ethylene oxide hydrolyzes to yield ethylene glycol, propylene oxide hydrolyzes to yield propylene glycol, and hexane oxide hydrolyzes to yield hexanediol. Additionally, propylene glycol can also be obtained through a dimethyl carbonate / propylene glycol co-production method. The epoxide hydrolysis method requires the prior preparation of the epoxide compound, increasing process complexity, reducing raw material utilization, and causing waste emissions, directly leading to increased costs. The co-production method also requires the prior production of the epoxide compound; furthermore, the price of co-produced products is always subject to market fluctuations.

[0004] US10214471 and US20180354878A1 disclose a method for reacting propylene and hydrogen peroxide in a reactor to obtain propylene glycol under the action of a heteropolyacid and a phase transfer catalyst. In this method, the heteropolyacid reacts with hydrogen peroxide in an aqueous phase to form a peroxide heteropolyacid salt, which is then reacted with the peroxide heteropolyacid salt to form a soluble salt in the organic phase via a phase transfer catalyst. In this method, an alkylated aromatic organic solvent with 8-12 carbon atoms increases the proportion of the heteropolyacid salt in the organic phase to complete the oxidation of propylene to propylene oxide. The heteropolyacid dissolves in water and continues to react with hydrogen peroxide; the resulting propylene oxide can enter the aqueous phase. Since the pH of the aqueous phase is maintained in the range of 1-3.5, the propylene oxide is hydrolyzed under the action of the acid in the aqueous phase to obtain propylene glycol. This method essentially only involves the two-step reaction of propylene epoxidation to propylene oxide and the hydrolysis of propylene oxide under acid to obtain propylene glycol, all carried out in a single reactor. The reaction requires a large amount of solvent and has a complex catalyst system, making the operation difficult.

[0005] EP1527057A1 discloses a method for the continuous preparation of propylene glycol. This method involves reacting propylene with hydrogen peroxide to produce propylene oxide, simultaneously generating propylene glycol as a byproduct. The generated propylene oxide is then reacted at 180-220°C and 15-25 bar to produce propylene glycol, which is then separated. This method is a physical integration of two steps: epoxidation and hydrolysis, and therefore cannot avoid the problems of low reaction efficiency and harsh hydrolysis conditions.

[0006] WO2019029808A1 discloses a method for preparing terminal 1,2-alkanediols with 5-12 carbon atoms, which involves reacting the corresponding terminal olefin with formic acid and hydrogen peroxide to obtain monoformate or diformate, and then decomposing them under the action of a decarbonization catalyst to obtain the corresponding diol and carbon monoxide.

[0007] CN103570493A discloses a method for synthesizing 1,2-vicinal diol via phase transfer catalytic oxidation using a supported heteropolyacid. The method involves mixing and reacting an acid, a terminal alkene, hydrogen peroxide, and a heteropolyacid phase transfer catalyst, followed by separation to obtain an epoxidized mixture. An alkaline solution is then added to maintain the pH at 10-12, and the mixture is further extracted by esterification and subjected to vacuum distillation to obtain the vicinal diol. This method has a long operational process and low product yield.

[0008] CN107879893A discloses a method for preparing vicinal diols via catalytic oxidation. The method involves preparing vicinal diols through the action of an olefin, an oxidant, and a bifunctional catalyst. The bifunctional catalyst contains silica-alumina molecular sieves, alumina, and titanium-silicon molecular sieves. This method uses an aluminum-containing catalyst, resulting in low utilization of hydrogen peroxide.

[0009] CN102452899A discloses a method for producing propylene glycol from propylene, which involves an epoxidation ring-opening hydration reaction of a titanium-silicon molecular sieve composite catalyst, propylene, and hydrogen peroxide to prepare propylene glycol. The titanium-silicon molecular sieve composite catalyst includes a titanium-silicon molecular sieve, an acidic molecular sieve, and a resin. However, this method has low hydrogen peroxide utilization.

[0010] CN104447204A discloses a method for preparing diols, which uses titanium-silicon molecular sieves supported on rare earth oxides as catalysts to promote the reaction of olefins and oxidants to produce diols. However, this method has low hydrogen peroxide utilization. Summary of the Invention

[0011] The purpose of this invention is to provide a method for preparing vicinal diols by direct oxidation of olefins. This method features mild reaction conditions, simple operation, high raw material conversion rate, high hydrogen peroxide utilization rate, and high selectivity for vicinal diols.

[0012] To achieve the above objectives, the present invention provides a method for preparing vicinal diols, characterized in that the method comprises reacting an olefin, an oxidant, and a substituted benzenesulfonic acid solution in the presence of a catalyst containing a titanium silicate molecular sieve to obtain a product containing a vicinal diol, wherein the substituted benzenesulfonic acid has the following structure:

[0013] R is selected from H, halogen, C1-C20 alkyl substituents, aryl substituents, ester substituents, carboxyl substituents, and halogen-containing substituents, and the number of substituents is 1-3.

[0014] The substituted benzenesulfonic acid is selected from one or more of methylbenzenesulfonic acid, dimethylbenzenesulfonic acid, ethylbenzenesulfonic acid, diethylbenzenesulfonic acid, isopropylphenylbenzenesulfonic acid, pentylbenzenesulfonic acid, cyclohexylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, phenylbenzenesulfonic acid, and p-chlorobenzenesulfonic acid; preferably, the substituted benzenesulfonic acid is selected from one or more of methylbenzenesulfonic acid, dimethylbenzenesulfonic acid, ethylbenzenesulfonic acid, diethylbenzenesulfonic acid, isopropylphenylbenzenesulfonic acid, pentylbenzenesulfonic acid, cyclohexylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, and octadecylbenzenesulfonic acid; more preferably, the substituted benzenesulfonic acid is selected from one or more of methylbenzenesulfonic acid, pentylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, and tetradecylbenzenesulfonic acid.

[0015] The molar ratio of the substituted benzenesulfonic acid to the titanium silicate molecular sieve is (0.005-0.3):1, preferably (0.01-0.1):1, and more preferably (0.02-0.08):1, wherein the titanium silicate molecular sieve is calculated as TiO2.

[0016] The titanium-silicon molecular sieve is at least one of MFI type titanium-silicon molecular sieve, MEL type titanium-silicon molecular sieve, BEA type titanium-silicon molecular sieve, MWW type titanium-silicon molecular sieve, MOR type titanium-silicon molecular sieve, TON type titanium-silicon molecular sieve, TUN type titanium-silicon molecular sieve and hexagonal titanium-silicon molecular sieve; preferably, the titanium-silicon molecular sieve is MFI type titanium-silicon molecular sieve.

[0017] The weight ratio of the titanium-silicon molecular sieve to the oxidant is (0.01-10):1.

[0018] The olefin is a mono- or polyolefin having C2-C30, preferably C2-C18, and more preferably C3-C8. The olefin may be selected from one or more of ethylene, vinyl chloride, propylene, allyl chloride, acrylonitrile, acrylic acid, acrolein, allyl alcohol, butenoic acid, isobutene, 1-butene, 2-butene, butadiene, 1-pentene, cyclopentene, 1,4-pentadiene, cyclopentadiene, isoprene, 1-hexene, cyclohexene, 1-heptene, 1-octene, cyclooctene, 1-decene, cyclododecene, styrene, styrene, oleic acid, methyl oleate, ricinoleic acid, and methyl ricinoleate.

[0019] The molar ratio of the oxidant to the olefin is (0.1-20):1.

[0020] The oxidant is selected from at least one of inorganic peroxides, organic peroxides, and ozone. The inorganic peroxide is at least one of hydrogen peroxide, urea peroxide, potassium persulfate, potassium persulfate, sodium percarbonate, percarbonamide, and sodium perborate. The organic peroxide is selected from at least one of tert-butyl hydroperoxide, cyclohexyl hydroperoxide, cumene peroxide, ethylbenzene hydroperoxide, benzoic acid peroxide, methyl ethyl ketone peroxide, tert-butyl perpentyl peroxide, isopropyl hydroperoxide, tert-amyl hydroperoxide, and di-tert-butyl peroxide. Preferably, the oxidant is hydrogen peroxide.

[0021] The titanium-silicon molecular sieve in the catalyst contains 20%-100% by weight, preferably 50%-100%, and more preferably 80%-100%.

[0022] In the method provided by this invention, the contact reaction uses one or more of the following solvents: water, C2-C20 ethers, C2-C20 acids, C2-C30 esters and their derivatives. Preferably, water is used as the solvent. The molar ratio of the oxidant to the solvent is 1:(3-200). The contact reaction is carried out at a temperature of 5℃-100℃, a pressure of atmospheric pressure to 5MPa, and a reaction time of 1min-24h.

[0023] The method for preparing vicinal diols provided by this invention involves a one-step reaction of an olefin with an oxidant and a substituted benzenesulfonic acid solution in a reactor in the presence of a titanium silicate molecular sieve to generate a product containing vicinal diols. Compared with existing methods, this method eliminates the need for prior preparation of epoxide compounds, simplifies the operation, provides milder reaction conditions, achieves higher raw material conversion rates, higher oxidant utilization, and higher selectivity for vicinal diols. The process is also safer and more efficient, making it suitable for large-scale industrial production applications. Detailed Implementation

[0024] This invention provides a method for preparing vicinal diols, comprising reacting an olefin, an oxidant, and a substituted benzenesulfonic acid solution in the presence of a catalyst containing a titanium silicate molecular sieve to obtain a product containing a vicinal diol, wherein the substituted benzenesulfonic acid has the following structure:

[0025]

[0026] R is selected from H, halogen, C1-C20 alkyl substituents, aryl substituents, ester substituents, carboxyl substituents, and halogen-containing substituents, and the number of substituents is 1-3.

[0027] The inventors unexpectedly discovered that adding a small amount of substituted benzenesulfonic acid to the reaction system can effectively promote the one-step oxidation of olefins to prepare vicinal diols. Compared with inorganic acids or carboxylic acids, the substituted benzenesulfonic acid used in this invention has better compatibility with the oil-water phase of the reaction system and the titanium-silicon molecular sieve catalyst, and is also safer.

[0028] According to the method of the present invention, the substituted benzenesulfonic acid has the following structure:

[0029]

[0030] Wherein R can be H, halogen, C1-C20 alkyl substituent, aryl substituent, ester substituent, carboxyl substituent, or halogen-containing substituent, and the number of substituents can be 1-3. Preferably, the substituted benzenesulfonic acid can be one or more of methylbenzenesulfonic acid, dimethylbenzenesulfonic acid, ethylbenzenesulfonic acid, diethylbenzenesulfonic acid, isopropylphenylbenzenesulfonic acid, pentylbenzenesulfonic acid, cyclohexylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, phenylbenzenesulfonic acid, and p-chlorobenzenesulfonic acid; further preferably, it is a benzenesulfonic acid having an alkyl substituent, for example, it can be one or more of methylbenzenesulfonic acid, dimethylbenzenesulfonic acid, ethylbenzenesulfonic acid, diethylbenzenesulfonic acid, isopropylphenylbenzenesulfonic acid, pentylbenzenesulfonic acid, cyclohexylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, and octadecylbenzenesulfonic acid. More preferably, the substituted benzenesulfonic acid is one or more of methylbenzenesulfonic acid, pentylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, and tetradecylbenzenesulfonic acid.

[0031] In this invention, the substituted benzenesulfonic acid and the titanium silicate molecular sieve together promote the oxidation of olefins to prepare vicinal diols. Both require appropriate ratios to maximize their effectiveness. According to the method of this invention, the molar ratio of the substituted benzenesulfonic acid to the titanium silicate molecular sieve (based on TiO2) is (0.005-0.3):1, preferably (0.01-0.1):1, and more preferably (0.02-0.08):1.

[0032] The titanium species in the framework of titanium-silicon molecular sieves possess excellent properties for activating oxidants to catalyze the oxidation of organic molecules. According to the method of the present invention, the titanium-silicon molecular sieve is a common type, such as MFI-type (e.g., TS-1), MEL-type (e.g., TS-2), BEA-type (e.g., Ti-β), MWW-type (e.g., Ti-MCM-22), MOR-type (e.g., Ti-MOR), TUN-type (e.g., Ti-TUN), hexagonal titanium-silicon molecular sieves (e.g., Ti-MCM-41, Ti-SBA-15), and other structural titanium-silicon molecular sieves (e.g., Ti-ZSM-48). Preferably, the titanium-silicon molecular sieve is selected from at least one of MFI-type, MEL-type, and BEA-type titanium-silicon molecular sieves. More preferably, the titanium-silicon molecular sieve is an MFI-type titanium-silicon molecular sieve. The MFI-type titanium-silicon molecular sieve described herein can be a TS-1 molecular sieve prepared by conventional methods such as hydrothermal synthesis or post-processing synthesis; it can be a titanium-silicon molecular sieve with a hierarchical porous structure (i.e., a pore distribution within the molecular sieve crystal in the range of 2-50 nm is obtained by fitting the molecular sieve pore distribution curve to the N2 adsorption-desorption curve using BJH fitting); it can be a hollow titanium-silicon molecular sieve (HTS) with an internal hollow structure (i.e., TEM characterization shows that there is one or more internal cavities within the molecular sieve crystal); or it can be a titanium-silicon molecular sieve with a plate-like, spherical, hexagonal prism shape, or an open surface. This invention does not impose specific limitations on these types. For better technical effects, the more preferred MFI-type titanium-silicon molecular sieve of this invention is a titanium-silicon molecular sieve with a hierarchical porous structure as described above and / or a hollow titanium-silicon molecular sieve (HTS) with a hollow structure.

[0033] According to the method of the present invention, the titanium-silicon molecular sieve can be used directly as a catalyst from raw molecular sieve powder, or it can be used after being shaped, for example, by pressing into tablets, by rolling to prepare microspheres or small sphere catalysts, by extrusion to prepare strip catalysts, by spray drying to prepare spherical catalysts, etc. Alternatively, the titanium-silicon molecular sieve can be directly added to the reaction of the present invention simultaneously or sequentially with other catalysts, co-catalysts, and inert matrix supports without being shaped. The present invention does not impose any limitations on this.

[0034] According to the method of the present invention, the catalyst containing titanium-silicon molecular sieve preferably contains 20%-100% by weight of titanium-silicon molecular sieve, more preferably 50%-100%, and even more preferably 80%-100%. In addition to titanium-silicon molecular sieve as the main catalyst, it may also contain binders, co-catalysts, pore expanders, inert matrix supports, etc.

[0035] According to the method of the present invention, the weight ratio of the titanium-silicon molecular sieve to the oxidant is (0.01-10):1, preferably (0.05-5):1, and more preferably (0.1-2):1.

[0036] According to the method of the present invention, there are no restrictions on the type of olefin used in the raw materials. The olefins can be monoolefins or polyolefins. The olefins can be aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and can have substituents, such as alkyl, aryl, ester, nitro, hydroxyl, carboxyl, aldehyde, ketone, cyano, ether, amino, imino, halogen substituents, and can contain oxygen, nitrogen, sulfur, phosphorus, and halogen heteroatoms. Preferably, the olefin is a C2-C30 mono-olefin or polyolefin, for example, it may be ethylene, vinyl chloride, propylene, propylene chloride, acrylonitrile, acrylic acid, acrolein, allyl alcohol, butenoic acid, isobutene, 1-butene, 2-butene, butadiene, 1-pentene, cyclopentene, 1,4-pentadiene, cyclopentadiene, isoprene, 1-hexene, cyclohexene, 1-heptene, 1-octene, cyclooctene, 1-decene, cyclododecene, styrene, styrene, oleic acid, methyl oleate, castor oil acid, methyl ricinoleate, more preferably a C2-C18, more preferably a C3-C8 mono-olefin or polyolefin.

[0037] According to the present invention, the olefin can be a single-component olefin, a mixed-component olefin, or a mixed olefin feedstock of olefin and inert components, such as nitrogen, argon, helium, neon, air, oxygen, hydrogen, methane, ethane, propane, and butane. In the mixed olefin feedstock, the molar content of the olefin is preferably greater than 20%, more preferably greater than 50%, further preferably greater than 70%, and most preferably greater than 90%. For safety reasons, the oxygen and hydrogen content in the mixed olefin feedstock is controlled; preferably, the molar content of oxygen and the molar content of hydrogen are each less than 5%, preferably less than 2%, and more preferably less than 1%.

[0038] According to the method of the present invention, the molar ratio of the oxidant to the olefin is (0.1-20):1, preferably (0.5-10):1, and more preferably (0.8-5):1.

[0039] According to the method of the present invention, the oxidant is at least one selected from inorganic peroxides, organic peroxides, and ozone. The inorganic peroxide is at least one selected from hydrogen peroxide, urea peroxide, potassium persulfate, potassium persulfate, sodium percarbonate, percarbonamide, and sodium perborate; the organic peroxide is at least one selected from tert-butyl hydroperoxide, cyclohexyl hydroperoxide, cumene peroxide, ethylbenzene hydroperoxide, benzoic acid peroxide, methyl ethyl ketone peroxide, tert-butyl perpentyl peroxide, isopropyl hydroperoxide, tert-amyl hydroperoxide, and di-tert-butyl peroxide. Hydrogen peroxide is a preferred oxidant.

[0040] Hydrogen peroxide is used in the form of hydrogen peroxide solution in this invention. This invention does not have specific requirements regarding the mass concentration of the hydrogen peroxide solution; preferably, the hydrogen peroxide solution is a solution with a hydrogen peroxide mass concentration of 2%-70%, more preferably 10%-50%, and even more preferably 20%-45%.

[0041] According to the method of the present invention, the contact reaction can be carried out in the presence of one or more of the following solvents: water, C2-C20 ethers, C2-C20 acids, C2-C30 esters and their derivatives. For example, it can be one or more of the following: dimethyl ether, diethyl ether, methyl tert-butyl ether, methyl cyclohexyl ether, anisole, acetic acid, propionic acid, butyric acid, malonic acid, octanoic acid, nonanoic acid, methyl formate, ethyl acetate, ethyl formate, butyl acetate, isopropyl acetate, cyclohexyl acetate, methyl oleate, ethyl oleate, and methyl castor oil. The molar ratio of the oxidant to the solvent is 1:(3-200), preferably 1:(5-80), and more preferably 1:(10-40).

[0042] Considering that adding organic solvents would require additional solvent separation, purification, and recovery units, increasing process complexity and energy consumption, from the perspective of optimizing the reaction process, reducing energy consumption, minimizing waste emissions, and improving the economics of the equipment, it is preferable to use water as the solvent instead of the aforementioned organic solvent. It is understood that the heterogeneous mass transfer resistance present during the reaction can be mitigated by existing technologies such as selecting a suitable reactor, adding internal components, and adjusting process parameters, which will not be elaborated upon here.

[0043] According to the method of the present invention, the conditions for the contact reaction are: a reaction temperature of 5-100°C, preferably 20-80°C, and a reaction pressure of atmospheric pressure to 5 MPa (gauge pressure). Within the reaction pressure range, the reaction system of the present invention can be a liquid-liquid-solid three-phase reaction, a gas-liquid-solid three-phase reaction, a liquid-solid two-phase reaction, or a gas-liquid-liquid-solid four-phase reaction. The reaction pressure can be the self-generated pressure formed by the reactants under the reaction conditions, or it can be introduced by introducing a gaseous component that is inert to the reaction. The gaseous component that is inert to the reaction includes, but is not limited to, nitrogen, argon, helium, neon, air, oxygen, methane, ethane, propane, butane, etc. For safety reasons, the oxygen content and hydrogen content in the reaction system are controlled, preferably with each molar content of oxygen and hydrogen being less than 5%, more preferably less than 2%, and more preferably less than 1%.

[0044] According to the method of the present invention, the reaction can be carried out under intermittent or continuous conditions. From the perspective of reducing labor intensity, improving product quality, and considering the feasibility and safety of the technology, continuous conditions are preferred. The contact reaction, i.e., the reaction time, is preferably 1 min to 24 h, or the feed mass hourly space velocity (WHSV) based on oxides is preferably 0.1 to 5 h. -1 .

[0045] According to the method of the present invention, the reaction can be carried out in batch or continuous reactions in different types of reactors such as batch reactors, fixed-bed reactors, tubular reactors, fluidized-bed reactors, suspended-bed reactors, and microchannel reactors. Different reactor types are only used to adapt to the corresponding purpose requirements and achieve better results in the one-step direct preparation of vicinal diols from olefins. At the same time, it is preferred to use appropriate catalysts in conjunction with the reactors. For example, fixed-bed reactors and tubular reactors use shaped catalysts, batch reactors use molecular sieve powder, and microchannel reactors use molecular sieve powder or immobilize the catalyst in microchannels to achieve relatively better reaction results. All of these should be considered as part of the present invention.

[0046] According to the method of the present invention, the reaction process mainly produces vicinal diols, mono-vicinal diols (i.e., condensation etherification products of 2 vicinal diol molecules), di-vicinal diols (i.e., condensation etherification products of 3 vicinal diol molecules), aldehydes generated from the double bond cleavage of the starting olefin, and acids obtained by further oxidation of the aldehydes. The substituted benzenesulfonic acid used in the reaction can be separated by distillation or extraction, while the unreacted olefins and the generated aldehydes can be separated by distillation. The generated vicinal diols, mono-vicinal diols, and di-vicinal diols can be separated under reduced pressure or by extraction, resulting in low overall separation energy consumption.

[0047] According to the method of the present invention, the separation of reaction products from catalyst can be achieved in various ways. For example, when using raw powdered titanium silicate molecular sieve as catalyst, the separation of products and the recycling and reuse of catalyst can be achieved by sedimentation, filtration, centrifugation, evaporation, membrane separation, etc. Alternatively, the catalyst can be shaped and loaded into a fixed-bed reactor, and the catalyst can be recovered after the reaction is completed. Various methods for the separation and recovery of catalysts are discussed in existing literature and will not be elaborated here.

[0048] The present invention will be further illustrated by the following examples, but these examples do not limit the scope of the invention.

[0049] The preparation method of the titanium-silicon molecular sieve TS-1 used in the examples is as follows (referring to the method in Zeolites, 1992, 12(8), 943-50): approximately 3 / 4 of a tetrapropylammonium hydroxide (TPAOH, 20%, purchased from Aldrich, USA) solution was added to a tetraethyl orthosilicate (TEOS) solution to obtain a liquid mixture with a pH of approximately 13. Then, under vigorous stirring, the required amount of tetrabutyl titanate [Ti(OBu)4] was added dropwise to the obtained liquid mixture. Anhydrous isopropanol solution was stirred for 15 minutes to obtain a clear liquid. Finally, the remaining TPAOH was slowly added to the clear liquid, and the mixture was stirred at 348-353 K for approximately 3 hours to obtain a sol with a chemical composition of 0.03TiO2:SiO2:0.36TPA:35H2O. This sol was then crystallized at 443 K for 3 days. The resulting solid was filtered, washed with distilled water, dried at 373 K for 5 hours, and then calcined at 823 K for 10 hours to obtain the molecular sieve sample. The amounts of TEOS, TPAOH, Ti(OBu)4, anhydrous isopropanol, and water were 42 g, 73 g, 2 g, 10 g, and 68 g respectively. In the titanium-silicon molecular sieve TS-1, the Ti:Si molar ratio was 0.03:1.

[0050] The hollow titanium-silicon molecular sieve (HTS) used in the examples was prepared according to the method described in Example 1 of Chinese Patent CN1301599A. In the HTS molecular sieve, the Ti:Si molar ratio is 0.03:1, and TEM characterization shows that there is an obvious hollow structure inside the molecular sieve crystal.

[0051] The Ti-beta preparation method used in the examples is as follows (referring to the method in Journal of Physical Chemistry B, 1998, 102:75-88): A certain amount of tetraethyl orthosilicate (TEOS) is added to a solution of tetraethylammonium hydroxide (TEAOH, 20%) and hydrogen peroxide, and hydrolyzed for 2 hours under stirring. Then, a weighed solution of anhydrous isopropanol of tetrabutyl titanate [Ti(OBu)4] is added to the hydrolysate of tetraethyl orthosilicate, and stirring is continued for 3 hours to remove alcohol, finally yielding a sol with the chemical composition TiO2:60SiO2:33TEAOH:400H2O:20H2O2. Finally, dealuminized molecular sieve seed crystals are added and stirred vigorously (the amount of seed crystals added is based on the sol as silica, 4g of seed crystals for every 100g of silica). The resulting mixture was crystallized at 413 K for 14 days. The resulting slurry was filtered, washed with water, dried at 373 K for 6 hours, and then calcined at 823 K for 12 hours to obtain a molecular sieve sample. The composition of the sample included 42 g of TEOS, 81 g of TEAOH, 1.16 g of Ti(OBu)₄, 10 g of anhydrous isopropanol, and 7.5 g of hydrogen peroxide. The Ti:Si molar ratio in the Ti-β molecular sieve was 0.016:1.

[0052] Unless otherwise specified, all raw materials used in the examples are chemically pure reagents.

[0053] In the examples, the reaction products were analyzed by gas chromatography, and the results were quantified using the external standard method. The chromatographic conditions were as follows: Agilent-6890 chromatograph, HP-5 capillary column, injection volume 0.5 μL, injection port temperature 280°C. The column temperature was held at 100°C for 2 min, then increased to 250°C at a rate of 15°C / min and held for 15 min. An FID detector was used, with a detector temperature of 280°C.

[0054] In the examples, the hydrogen peroxide content was measured using the indirect titration method with sodium thiosulfate, and the hydrogen peroxide was measured as hydrogen peroxide.

[0055] The following indicators were mainly examined in each embodiment and comparative example:

[0056] Olefin conversion rate = (Number of moles of olefins consumed in the formation of each substance in the product) / (Number of moles of olefins in the feedstock) × 100%

[0057] Selectivity for vicinal diols = (Number of moles of vicinal diols in the product) / (Number of moles of olefins consumed in the formation of main and by-products) × 100%

[0058] Effective utilization rate of hydrogen peroxide = (moles of hydrogen peroxide consumed in the formation of organic matter in the product) / (moles of hydrogen peroxide in the raw materials before the reaction - moles of hydrogen peroxide in the product after the reaction) × 100%

[0059] Example 1

[0060] TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to propylene was 2:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.03:1, and the molar ratio of hydrogen peroxide to water was 1:20. The mixture in the reactor was then reacted at 60℃ and 2MPa for 3 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0061] Example 2

[0062] TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to propylene was 2:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.08:1, and the molar ratio of hydrogen peroxide to water was 1:15. The mixture in the reactor was then reacted at 40℃ and 3MPa for 3 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0063] Example 3

[0064] TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.5:1, the molar ratio of hydrogen peroxide to propylene was 3:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.08:1, and the molar ratio of hydrogen peroxide to water was 1:30. The mixture in the reactor was then reacted at 60℃ and 4MPa for 4 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0065] Example 4

[0066] TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, dodecylbenzenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.3:1, the molar ratio of hydrogen peroxide to propylene was 1.5:1, the molar ratio of dodecylbenzenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.02:1, and the molar ratio of hydrogen peroxide to water was 1:20. The mixture in the reactor was then reacted at 70℃ and 4MPa for 2 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0067] Example 5

[0068] TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, dodecylbenzenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 1:1, the molar ratio of hydrogen peroxide to propylene was 1.5:1, the molar ratio of dodecylbenzenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.08:1, and the molar ratio of hydrogen peroxide to water was 1:20. The mixture in the reactor was then reacted at 50℃ and 2MPa for 3 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0069] Example 6

[0070] TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 1:1, the molar ratio of hydrogen peroxide to propylene was 2:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.08:1, and the molar ratio of hydrogen peroxide to water was 1:15. The mixture in the reactor was then reacted at 50℃ and 2MPa for 4 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0071] Example 7

[0072] TS-1 molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were introduced into a microchannel reactor manufactured by Corning Incorporated. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to propylene was 2:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.02:1, and the molar ratio of hydrogen peroxide to water was 1:10. The mixture was then reacted at 50°C and 1.5 MPa for 5 min. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0073] Example 8

[0074] TS-1 molecular sieve, 1-butene, 30% by mass hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to 1-butene was 2:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.03:1, and the molar ratio of hydrogen peroxide to water was 1:20. The mixture in the reactor was then reacted at 80℃ and 0.5MPa for 3 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0075] Example 9

[0076] TS-1 molecular sieve, allyl chloride, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to allyl chloride was 1.2:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.05:1, and the molar ratio of hydrogen peroxide to water was 1:20. The mixture in the reactor was then reacted at 40℃ and 0.2MPa for 2 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0077] Example 10

[0078] HTS molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, dodecylbenzenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.15:1, the molar ratio of hydrogen peroxide to propylene was 1.5:1, the molar ratio of dodecylbenzenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.02:1, and the molar ratio of hydrogen peroxide to water was 1:10. The mixture in the reactor was then reacted at 40℃ and 2MPa for 4 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0079] Example 11

[0080] HTS molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.15:1, the molar ratio of hydrogen peroxide to propylene was 1.8:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.03:1, and the molar ratio of hydrogen peroxide to water was 1:15. The mixture in the reactor was then reacted at 50℃ and 3MPa for 4 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0081] Example 12

[0082] HTS molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, dodecylbenzenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to propylene was 1.8:1, the molar ratio of dodecylbenzenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.03:1, and the molar ratio of hydrogen peroxide to water was 1:10. The mixture in the reactor was then reacted at 50℃ and 2MPa for 3 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0083] Example 13

[0084] HTS molecular sieve, propylene, 30% (w / w) hydrogen peroxide solution, p-toluenesulfonic acid, and water were added to a reactor. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.2:1, the molar ratio of hydrogen peroxide to propylene was 1.5:1, the molar ratio of p-toluenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.02:1, and the molar ratio of hydrogen peroxide to water was 1:15. The mixture in the reactor was then reacted at 40℃ and 2MPa for 3 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0085] Example 14

[0086] Ti-β molecular sieve, 1-hexene, 30% by mass hydrogen peroxide solution, pentylbenzenesulfonic acid, and water were added to a reaction vessel. The molar ratio of titanium-silicon molecular sieve to hydrogen peroxide was 0.5:1, the molar ratio of hydrogen peroxide to 1-hexene was 3:1, the molar ratio of pentylbenzenesulfonic acid to titanium-silicon molecular sieve (based on TiO2) was 0.02:1, and the molar ratio of hydrogen peroxide to water was 1:20. The mixture in the reaction vessel was then reacted at 60℃ and 0.2MPa for 3 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0087] Example 15

[0088] TS-1 molecular sieve, methyl oleate, 30% (w / w) hydrogen peroxide solution, decylbenzenesulfonic acid, and butyl acetate were added to a reaction vessel. The molar ratio of titanium silicate molecular sieve to hydrogen peroxide was 0.08:1, the molar ratio of hydrogen peroxide to propylene was 1.5:1, the molar ratio of decylbenzenesulfonic acid to titanium silicate molecular sieve (based on TiO2) was 0.1:1, and the molar ratio of hydrogen peroxide to butyl acetate was 1:15. The mixture in the reaction vessel was then reacted at 50°C and atmospheric pressure for 6 hours. After the reaction was completed, samples were taken for analysis, and the results are shown in Table 1.

[0089] Comparative Example 1

[0090] Unlike Example 1, p-toluenesulfonic acid was not added. The analytical results are shown in Table 1.

[0091] Comparative Example 2

[0092] Unlike Example 1, TS-1 molecular sieve was not added. The analytical results are shown in Table 1.

[0093] Comparative Example 3

[0094] The difference from Example 1 is that sulfuric acid was used instead of p-toluenesulfonic acid. The analytical results are shown in Table 1.

[0095] Comparative Example 4

[0096] TS-1 molecular sieves loaded with cerium dioxide were prepared according to the method of Example 1 of Chinese Patent CN104447204A, and the reaction was evaluated according to the method of Example 1 of this invention. In this case, the reaction process did not involve the addition of p-toluenesulfonic acid, and CeO2 / TS-1 was used as the catalyst. The analytical results after the reaction are shown in Table 1.

[0097] Table 1

[0098]

[0099]

[0100] As can be seen from the results of Examples 1-13 and Comparative Examples 1-4, the method of the present invention for preparing vicinal diols is simple to operate, has mild reaction conditions, high olefin conversion and vicinal diol selectivity, high effective utilization of hydrogen peroxide, and is safe and controllable, making it suitable for large-scale industrial production applications.

Claims

1. A method for preparing vicinal diols, characterized in that... This method involves contacting an olefin, an oxidant, and a substituted benzenesulfonic acid solution in the presence of a catalyst containing a titanium silicate molecular sieve, using water as a solvent, to obtain a product containing a vicinal diol. The molar ratio of the oxidant to water is 1:(3-200). The substituted benzenesulfonic acid is selected from one or more of methylbenzenesulfonic acid, dimethylbenzenesulfonic acid, ethylbenzenesulfonic acid, diethylbenzenesulfonic acid, isopropylphenylbenzenesulfonic acid, pentylbenzenesulfonic acid, cyclohexylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, phenylbenzenesulfonic acid, and p-chlorobenzenesulfonic acid. The titanium silicate molecular sieve is an MFI type titanium silicate molecular sieve, a MEL type titanium silicate molecular sieve, or a BE type titanium silicate molecular sieve. The olefin is selected from at least one of the following: type A titanium-silicon molecular sieve, MWW type titanium-silicon molecular sieve, MOR type titanium-silicon molecular sieve, TON type titanium-silicon molecular sieve, TUN type titanium-silicon molecular sieve, and hexagonal titanium-silicon molecular sieve; the olefin is selected from one or more of the following: vinyl chloride, propylene, propylene chloride, acrylonitrile, acrylic acid, acrolein, allyl alcohol, butenoic acid, isobutene, 1-butene, 2-butene, butadiene, 1-pentene, cyclopentene, 1,4-pentadiene, cyclopentadiene, isoprene, 1-hexene, cyclohexene, 1-heptene, 1-octene, cyclooctene, 1-decene, cyclododecene, styrene, styrene, oleic acid, methyl oleate, ricinoleic acid, and methyl ricinoleate; the oxidant is hydrogen peroxide.

2. The method according to claim 1, wherein, The substituted benzenesulfonic acid is selected from one or more of methylbenzenesulfonic acid, dimethylbenzenesulfonic acid, ethylbenzenesulfonic acid, diethylbenzenesulfonic acid, isopropylphenylbenzenesulfonic acid, pentylbenzenesulfonic acid, cyclohexylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, and octadecylbenzenesulfonic acid.

3. The method according to claim 1, wherein, The substituted benzenesulfonic acid is selected from one or more of methylbenzenesulfonic acid, pentylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, and tetradecylbenzenesulfonic acid.

4. The method according to claim 1, wherein, The molar ratio of the substituted benzenesulfonic acid to the titanium silicate molecular sieve is (0.005-0.3):1, and the titanium silicate molecular sieve is calculated as TiO2.

5. The method according to claim 4, wherein, The molar ratio of the substituted benzenesulfonic acid to the titanium silicate molecular sieve is (0.01-0.1):

1.

6. The method according to claim 5, wherein, The molar ratio of the substituted benzenesulfonic acid to the titanium silicate molecular sieve is (0.02-0.08):

1.

7. The method according to claim 1, wherein, The titanium-silicon molecular sieve is an MFI type titanium-silicon molecular sieve.

8. The method according to claim 1, wherein, The weight ratio of the titanium-silicon molecular sieve to the oxidant is (0.01-10):

1.

9. The method according to claim 1, wherein, The molar ratio of the oxidant to the olefin is (0.1-20):

1.

10. The method according to claim 1, wherein, The catalyst containing titanium-silicon molecular sieve has a weight content of 20%-100% titanium-silicon molecular sieve.

11. The method according to claim 10, wherein, The catalyst containing titanium-silicon molecular sieves has a weight content of 50%-100% titanium-silicon molecular sieves.

12. The method according to claim 11, wherein, The catalyst containing titanium-silicon molecular sieves has a weight content of 80%-100% titanium-silicon molecular sieves.

13. The method according to claim 1, wherein, The contact reaction is carried out at a temperature of 5℃-100℃, a pressure of atmospheric pressure to 5MPa, and a reaction time of 1min-24h.

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