A method for preparing alcohol using light gasoline

Abstract

The present invention is mainly applied to the field of fine chemicals, and provides a method for generating alcohol by hydration reaction using water and olefins in light gasoline components as raw materials and using acidic ion exchange resin as catalyst in a fixed bed reactor. Light gasoline uses catalytic cracking gasoline from a refinery, with a dry point of 30-70°C, a hydration reaction temperature of 20-100°C, and a reaction pressure of 0.5-1.0MPa. Under the action of a strong acidic cation exchange resin catalyst, C4, C5 and C6 olefins in the raw materials will respectively undergo hydration reactions with water to generate corresponding alcohols. The method provided by the present invention is simple in process, has a long catalyst life, is easy to obtain raw materials, and does not generate three wastes.

Description

Technical Field

[0001] The invention belongs to the technical field of alcohols, and in particular relates to a method for preparing alcohols from light gasoline, specifically a method for producing butanol, pentanol and hexanol by hydration of olefins, which can realize efficient utilization of light gasoline in refineries to produce high value-added products. Background Art

[0002] Alcohol is a commonly used organic chemical raw material. 2-Butanol, 2-methyl-2-butanol and 2-methyl-2-pentanol are widely used in the synthesis and production of medicines, pesticides, dyes, auxiliaries and additives. At present, the raw materials for producing such alcohols are all high-purity single-component olefins, which are expensive and costly. However, light gasoline resources such as C5 have a high olefin content and are not suitable for direct blending into gasoline for oil blending. Generally, they are etherified or aromatized by modification to increase their octane number. However, in addition to being used as a raw material for oil blending through various channels, light gasoline can also be converted into chemical products to increase its use value. The gasoline produced by the FCC unit of the refinery contains more olefins and is a high-quality hydration raw material. Therefore, the use of light gasoline to hydrate under acidic catalyst conditions to prepare mixed alcohols is a feasible path because the reaction conditions are mild and environmentally friendly.

[0003] Under normal circumstances, water is insoluble in light gasoline. The use of polar organic solvents can improve the mutual solubility of light hydrocarbons and water, such as ketones, alcohols and ethers, which can make the originally immiscible two phases become homogeneous, which greatly increases the feasibility of olefins and water reacting at the catalyst active site, thereby improving the conversion rate of olefins in light gasoline. The prior art uses 2-methyl-1-butene and 2-methyl-2-butene, two isopentene, as raw materials, and acetone as solvent to prepare tert-amyl alcohol by hydration. However, the raw materials used in the above method are pure isopentene, which is relatively expensive. Secondly, high-concentration isopentene will undergo polymerization of olefins under the catalytic action of strongly acidic cation exchange resin to generate macromolecular hydrocarbon compounds, affecting the purity of the product. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for preparing alcohol from light gasoline. The method provided by the present invention is not prone to polymerization to generate heavy components, and the reaction conditions are mild, which is convenient for industrialization.

[0005] The present invention provides a method for preparing alcohol by hydrating light gasoline, comprising:

[0006] Under the action of a catalyst, light gasoline, water and a polar solvent react to obtain alcohol.

[0007] Preferably, the catalyst is selected from strongly acidic cation exchange resins.

[0008] Preferably, the light gasoline contains low-carbon olefins.

[0009] Preferably, the reaction is carried out in a fixed bed reactor.

[0010] Preferably, the volume space velocity during the reaction is 0.2 to 1.5 h -1 .

[0011] Preferably, the reaction temperature is 20-120°C.

[0012] Preferably, the reaction pressure is 0.3-1.5 MPa.

[0013] Preferably, the polar solvent is selected from one or more of ethanol, n-propanol, isopropanol and n-butanol.

[0014] Preferably, the catalyst filling volume is 10-500 ml, the mass concentration of olefins in light gasoline is greater than 60%, and the molar ratio of water, olefins in light gasoline and solvent is (1-7):1:(1-7).

[0015] Preferably, the light gasoline is the light component of gasoline after full-fraction hydrogenation.

[0016] The method provided by the present invention can efficiently utilize light gasoline from refineries for direct hydration to produce high-end chemical products. The method provided by the present invention has mild reaction conditions, low operating difficulty, is environmentally friendly, has a high olefin conversion rate, has high product purity, contains no by-products, and is convenient for industrial continuous production. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] The present invention provides a method for preparing alcohol by hydrating light gasoline, comprising:

[0019] Under the action of a catalyst, light gasoline, water and a polar solvent react to obtain alcohol.

[0020] In the present invention, the catalyst is preferably selected from strongly acidic cation exchange resins, and the strongly acidic cation exchange resin can be 001×7 catalyst provided by Dandong Mingzhu Special Resin Co., Ltd.

[0021] In the present invention, the light gasoline preferably contains olefins, more preferably low-carbon olefins; the mass content of olefins in the light gasoline is preferably greater than 60%, more preferably 65-70%.

[0022] In the present invention, the light gasoline is preferably a gasoline component produced by catalytic cracking in a refinery. After full fraction hydrogenation, the mercaptan sulfur with a lower boiling point reacts with diolefins to generate high-boiling sulfide and is transferred to the heavy gasoline. At the same time, the remaining diolefins are partially saturated. The light gasoline component after hydrogenation still retains a large amount of olefin components and can be used as a raw material for hydration reaction after water washing.

[0023] In the present invention, the light gasoline after hydrogenation of the whole fraction does not contain dienes as determined by the maleic anhydride method, wherein the mass content of mercaptan sulfur is preferably 0.0003-0.0005%, more preferably 0.0004%; the dry point is preferably 30-70°C, more preferably 40-60°C, and most preferably 49.9°C. In the present invention, the mass content of mercaptan sulfur in the light gasoline is preferably less than 5ppm; the mass content of dienes is preferably less than 50ppm.

[0024] In the present invention, the light gasoline is preferably a light component of gasoline after full-fraction hydrogenation, including C4, C5 and C6 components, with C5 being the largest component.

[0025] In the present invention, the light gasoline preferably includes: a C4 component, a C5 component and a C6 component.

[0026] In the present invention, the mass content of the C4 component in light gasoline is preferably 3-4%, more preferably 3.3%; the mass content of the olefins in the C4 component in light gasoline is preferably 1.8-2.2%, more preferably 2.1%; the olefins in the C4 component are preferably 2-butene.

[0027] In the present invention, the mass content of the C5 component in light gasoline is preferably 70-75%, more preferably 72-74%, and most preferably 72.8%; the mass content of the olefins in the C5 component in light gasoline is preferably 43-47%, more preferably 44-46%, and most preferably 45.4%; the olefins in the C5 component are preferably isopentene; the mass content of the isopentene in light gasoline is preferably 20-25%, more preferably 21-23%, and most preferably 22.06%. In the present invention, the mass content of highly active 2-methyl-1-butene in the C5 component is preferably greater than 10%, and more preferably 12%.

[0028] In the present invention, the mass content of the C6 component in the light gasoline is preferably 20-25%, more preferably 23-25%, and most preferably 23.9%; the mass content of the olefins in the C6 component in the light gasoline is preferably 15-20%, more preferably 17-19%, and most preferably 17.54%; the olefins in the C6 component are preferably 2-methyl-1-pentene and 2-methyl-2-pentene. In the present invention, the mass content of 2-methyl-1-pentene is preferably greater than 12%, and more preferably 12.5%.

[0029] In the present invention, the polar solvent is preferably selected from ethanol, n-propanol, isopropanol and n-butanol.

[0030] In the present invention, the amounts of the catalyst, light gasoline, water and polar solvent are respectively: the catalyst filling volume is 10-500 ml, the mass concentration of olefins in light gasoline is greater than 60%, the molar ratio of olefins in water and hydrogen gasoline to solvent is preferably (1-7):1:(1-7), more preferably (2-6):1:(2-6), and most preferably (3-5):1:(3-5). The amount ratio of the catalyst to water is preferably (10-500) ml:(1-7) mol, more preferably (50-400) ml:(2-6) mol, more preferably (100-300) ml:(3-5) mol, and most preferably 200 ml:4 mol.

[0031] In the present invention, the amount of water mixed with light gasoline is preferably excessive. A high water-olefin ratio can increase the conversion rate of olefins. The molar ratio of water to olefins in light gasoline is preferably (1-7):1, more preferably (2-6):1, and most preferably (3-5):1.

[0032] In the present invention, the reaction is preferably carried out in a fixed bed reactor; the volume space velocity during the reaction is preferably 0.2 to 1.5 h -1 , more preferably 0.3 to 1.2 h -1 , the most preferred time is 0.5 to 1 h -1 The reaction temperature is preferably 20 to 120°C, more preferably 40 to 80°C, more preferably 50 to 70°C, and most preferably 65°C; the reaction pressure is preferably 0.3 to 1.5 MPa, more preferably 0.4 to 1.0 MPa, and most preferably 0.5 to 0.8 MPa;

[0033] In the present invention, the loading amount of the catalyst in the reaction process is preferably 50-200ml, more preferably 80-150ml, and most preferably 100-120ml; the two sides of the catalyst in the reaction process are preferably blocked with inert alumina ceramic balls and quartz sand. In the present invention, the two sides of the catalyst in the reaction process are preferably loaded with quartz sand, and the sides of the quartz sand are preferably loaded with alumina ceramic balls; the loading amount of the quartz sand is preferably 8-12ml, more preferably 10ml; the particle size of the quartz sand is preferably 35-45 mesh, more preferably 40 mesh; the loading amount of the alumina ceramic balls is preferably 80-120ml, more preferably 90-110ml, and most preferably 100ml; the diameter of the alumina ceramic balls is preferably 2-4mm, more preferably 3mm.

[0034] In the present invention, after the reaction is completed, it is preferred that the following steps are further included:

[0035] The obtained reaction product was cooled.

[0036] In the present invention, the cooling is preferably carried out in a low temperature cooling tank; the cooling temperature is preferably -5 to 5°C, more preferably -3 to 3°C, and most preferably 0°C.

[0037] In the present invention, the method for preparing alcohol by light gasoline hydration method preferably comprises:

[0038] Light gasoline containing low-carbon olefins is mixed with water and polar alcohol solvent as raw materials, pumped into a fixed bed reactor through a raw material pump, and enters a reaction tube equipped with a strong acid ion exchange resin catalyst for hydration reaction. The product after the reaction is cooled in a low-temperature cooling tank and then enters a product collection tank. The volume space velocity of the mixed raw materials is 0.2-1.5h -1 , the reaction temperature is 20-120°C, and the pressure of the reaction system is 0.3-1.5MPa.

[0039] In the present invention, the mixed liquid preferably flows into a product collection tank after being cooled, and the product is detected by GC analysis.

[0040] In the present invention, the synthesis reaction equation is as follows:

[0041] (1) Formation of C4 alcohols

[0042]

[0043] (2) Formation of C5 alcohols

[0044]

[0045] (3) Formation of C6 alcohols

[0046]

[0047] The method provided by the present invention can efficiently utilize light gasoline from refineries to directly hydrate and produce high-end chemical products. The reaction conditions are mild, the operation difficulty is low, it is environmentally friendly, the olefin conversion rate is high, the product purity is high, and it does not contain by-products, which is convenient for industrial continuous production.

[0048] Example 1

[0049] A fixed bed reactor was used, with olefin-rich light gasoline from Jingbo Petrochemical as the raw material, isopropanol as the solvent, and Dandong Mingzhu's 001×7 strong acid cation exchange resin as the catalyst to react with water to prepare alcohol. The catalyst loading was 100 ml, the reaction temperature was 65 ° C, the reaction pressure was 0.8 MPa, and the volumetric space velocity of the mixed raw materials was 1.0 h -1 .

[0050] Light gasoline is a gasoline component produced by the catalytic cracking unit of Jingbo Petrochemical. After full-fraction hydrogenation, the light component at the top of the tower can be used as a raw material for hydration reaction after water washing. The light gasoline after full-fraction hydrogenation is determined by the maleic anhydride method to contain no dienes, of which the mercaptan sulfur content is 0.0004% and the dry point is 49.9°C. The C4 component content in light gasoline is 3.3%, of which the olefin content is 2.1%, mainly 2-butene; the C5 component content is 72.8%, the olefin content is 45.4%, and the isopentene content is 22.06%; the C6 component content is 23.9%, and the olefin content is 17.5%, mainly 2-methyl-1-pentene and 2-methyl-2-pentene.

[0051] The raw material ratio of hydration reaction is 4:1:6.5 in molar ratio of water, olefins in light gasoline and solvent. The catalyst loading is 100 ml. 10 ml of 40-mesh quartz sand is loaded on both sides. 100 ml of alumina ceramic balls with a diameter of 3 mm are loaded on both sides of the quartz sand.

[0052] After the reaction is completed, the cooling temperature of the low-temperature cooling tank is 0°C, and the product mixture flows into the product collection tank after cooling. The product is detected by GC analysis.

[0053] Example 2

[0054] Alcohol was prepared according to the method of Example 1, except that the molar ratio of water, olefins in light gasoline and solvent was 5:1:6.5.

[0055] Example 3

[0056] Alcohol was prepared according to the method of Example 1, except that the molar ratio of water, olefins in light gasoline and solvent was 6:1:6.5.

[0057] Example 4

[0058] Alcohol was prepared according to the method of Example 2, except that the reaction temperature was 60°C.

[0059] Example 5

[0060] Alcohol was prepared according to the method of Example 2, except that the reaction temperature was 70°C.

[0061] Comparative Example 1

[0062] Alcohol was prepared according to the method of Example 2, which differs from Example 2 in that the raw materials used were olefins, including 2-methyl-1-butene and 2-methyl-2-butene, the mass concentration of 2-methyl-1-butene in the raw materials was 47.55%, the mass concentration of 2-methyl-2-butene in the raw materials was 52.11%, and the molar ratio of water, olefins and solvent remained unchanged.

[0063] Performance Testing

[0064] Cyclohexanone was used as the internal standard and the gas chromatography internal standard method was used to detect the conversion rate and selectivity:

[0065]

[0066]

[0067] The test results are as follows:

[0068]

[0069]

[0070] The method provided by the present invention can efficiently utilize light gasoline from refineries for direct hydration to produce high-end chemical products. The method provided by the present invention has mild reaction conditions, low operating difficulty, is environmentally friendly, has a high olefin conversion rate, has high product purity, contains no by-products, and is convenient for industrial continuous production.

[0071] Although the present invention has been described and illustrated with reference to specific embodiments of the present invention, these descriptions and illustrations do not limit the present invention. It will be clearly understood by those skilled in the art that various changes may be made without departing from the true spirit and scope of the present invention as defined by the appended claims, so that specific circumstances, materials, material compositions, materials, methods or processes are suitable for the goals, spirit and scope of the present application. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a specific order, it should be understood that these operations may be combined, subdivided or reordered to form equivalent methods without departing from the teachings of the present invention. Therefore, unless specifically indicated herein, the order and grouping of operations are not limitations of the present application.

Claims

1. A method for preparing alcohol by hydration of light gasoline, comprising: Under the action of a catalyst, light gasoline, water and a polar solvent react to obtain alcohol; The catalyst is selected from 001×7 strongly acidic cation exchange resin; The light gasoline contains low-carbon olefins; the light gasoline includes: a C4 component content of 3.3%, of which an olefin content of 2.1%, mainly 2-butene; a C5 component content of 72.8%, an olefin content of 45.4%, and an isopentene content of 22.06%; a C6 component content of 23.9%, an olefin content of 17.5%, mainly 2-methyl-1-pentene and 2-methyl-2-pentene; The reaction was carried out in a fixed bed reactor; the volume space velocity during the reaction was 1.0 h -1 ; The reaction temperature is 65°C; The reaction pressure is 0.8MPa; The polar solvent is selected from isopropanol; The catalyst filling volume is 100 ml, and the molar ratio of water, olefins in light gasoline and solvent is 5:1:6.

5.

2. The method according to claim 1, characterized in that The light gasoline is the light component of catalytic gasoline after full-fraction hydrogenation.

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