A one-step method for preparing bio-based isooctyl alcohol from n-butanol

Abstract

The invention discloses a method for preparing bio-based isooctyl alcohol from n-butanol in one step. The method comprises continuously feeding bio-based n-butanol and nitrogen into a reactor at the same time, and synthesizing bio-based isooctyl alcohol in one step under the action of a multifunctional copper-based catalyst; the catalyst comprises the following composition based on 100% of the total mass: 15-60% copper, 10-45% zinc oxide, and 20-50% titanium dioxide. The present invention utilizes a multifunctional copper-based catalyst to achieve coupling of n-butanol dehydrogenation, n-butyraldehyde condensation dehydration, and octenal hydrogenation reactions, and has high reaction conversion rate and selectivity.

Description

Technical Field

[0001] The invention relates to a method for synthesizing a bio-based compound, in particular to a method for preparing bio-based isooctyl alcohol from n-butanol in one step. Background Art

[0002] As an important chemical raw material, isooctyl alcohol can react with oxygen-containing inorganic or organic acids to form esters, react with phosphorus pentachloride to form chlorooctane, react with hydrohalic acid to form halooctane, and dehydrate two isooctyl alcohol molecules to form ethers. Isooctyl alcohol is mainly used to make phthalic acid esters and aliphatic dibasic acid ester plasticizers such as dioctyl phthalate, dioctyl azelate and dioctyl sebacate, which are used as the main plasticizer and cold-resistant auxiliary plasticizer, defoamer, dispersant, mineral processing agent and petroleum additive for plastics, and is also used in printing and dyeing, paint, film and other aspects.

[0003] With the continuous improvement of living standards and the country's further advocacy of biomass and bio-based materials, the demand for bio-based isooctyl alcohol in the sunscreen and moisturizer industries has become increasingly prominent. However, the main production process of isooctyl alcohol is to hydroformylate propylene to produce n-butyraldehyde, which is then condensed and dehydrated to produce octenal, and then hydrogenated to produce isooctyl alcohol. The raw material propylene is from fossil sources, which does not meet the requirements of daily necessities for raw material safety. Therefore, the demand for changing the isooctyl alcohol production route and using bio-based raw materials to produce bio-based isooctyl alcohol has received increasing attention.

[0004] The current mainstream method for preparing bio-based isooctyl alcohol is to use crotonaldehyde as raw material, selectively hydrogenate it to produce n-butyraldehyde, then condense and dehydrate it in the presence of an alkaline catalyst to produce octenal, and finally hydrogenate it to produce isooctyl alcohol. However, the process is complicated, and the condensation and dehydration reaction of n-butyraldehyde in industry mostly uses dilute sodium hydroxide solution as a catalyst, which has problems such as severe corrosion to equipment, large wastewater discharge, and environmental pollution.

[0005] In order to avoid the problems caused by using dilute alkali liquid catalyst in the condensation reaction of n-butyraldehyde, patent CN115028524A provides a method for converting crotonaldehyde into isooctylaldehyde in one step by a nickel-zirconium catalyst supported by biomass charcoal, but the method introduces a solvent into the reaction raw materials, which increases the separation operation, and the obtained isooctylaldehyde still needs to be further hydrogenated to prepare isooctyl alcohol. CN114933514A proposes a method for converting crotonaldehyde into isooctyl alcohol by layering two catalysts in a fixed bed. The method has a high yield for preparing isooctyl alcohol, but the reaction process uses a precious metal palladium-based catalyst, which is costly and has high requirements for the loading and temperature control of the catalyst. In addition, the raw material crotonaldehyde is also a highly toxic material, which has high requirements for the design of the equipment. Patent CN101823938B uses a metal catalyst with hydroxyapatite as a carrier to realize the one-step catalytic condensation of n-butanol to prepare isooctyl alcohol, but the isooctyl alcohol selectivity of the innovative route is less than 80%, and the industrialization difficulty is relatively large, so it is also necessary to develop a more economical and industrializable bio-based isooctyl alcohol preparation technology. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a one-step method for preparing bio-based isooctyl alcohol from n-butanol. The present invention uses a multifunctional copper-based catalyst to achieve the coupling of n-butanol dehydrogenation, n-butyraldehyde condensation dehydration and octenal hydrogenation reaction. Compared with the existing process, the process shortens the process flow, the equipment is simple, and the generation of organic alkaline wastewater and the use of highly toxic material crotonaldehyde are avoided, which is safer and more environmentally friendly.

[0007] A method for preparing bio-based isooctyl alcohol from n-butanol in one step, comprising continuously feeding bio-based n-butanol and nitrogen into a reactor simultaneously, and synthesizing bio-based isooctyl alcohol in one step under the action of a multifunctional copper-based catalyst;

[0008] The catalyst, taking the total mass as 100%, comprises the following components:

[0009] Copper 15-60%, zinc oxide 10-45%, titanium dioxide 20-50%,

[0010] Preferably, it comprises the following components:

[0011] Copper 35-55%, zinc oxide 15-30%, titanium dioxide 30-45%.

[0012] As a preferred embodiment of the present invention, the processing amount of the catalyst is 0.1-5 g bio-based n-butanol / (g catalyst·h), preferably 0.5-2 g bio-based n-butanol / (g catalyst·h).

[0013] As a preferred embodiment of the present invention, the molar ratio of nitrogen to bio-based n-butanol is 1-50, preferably 5-25.

[0014] As a preferred embodiment of the present invention, the reaction temperature in the reactor is 150-300° C., preferably 180-280° C., and the reaction pressure is normal pressure.

[0015] As a preferred embodiment of the present invention, the catalyst is loaded in a reactor, the raw materials of bio-based n-butanol and nitrogen enter from the upper end of the reactor, the reaction materials flow out from the lower end of the reactor and then undergo gas-liquid separation, the liquid phase is collected, and a reaction liquid containing bio-based isooctyl alcohol is obtained.

[0016] As a preferred embodiment of the present invention, the reactor is a fixed bed reactor.

[0017] As a preferred embodiment of the present invention, the bio-based n-butanol is derived from a byproduct of the process of preparing bio-based 1,3-butanediol by acetaldehyde condensation hydrogenation. The preparation of bio-based 1,3-butanediol by acetaldehyde condensation hydrogenation has been reported in many known technologies (such as patents US6900360B2 and TW295577B), and a certain amount of n-butanol (about 3-20% of the mass of 1,3-butanediol) is produced as a byproduct in industrial production, which can be preferentially used as a source of bio-based n-butanol in this application to further prepare bio-based isooctyl alcohol.

[0018] As a preferred embodiment of the present invention, the catalyst is prepared by at least one of a coprecipitation method, a hydrothermal method, an adsorption method, an impregnation method, and a sol-gel method, preferably a coprecipitation method.

[0019] As a preferred embodiment of the present invention, the preparation method of the catalyst is as follows:

[0020] Soluble salts of copper, zinc, titanium and urea are dissolved in deionized water, and the mixed solution is transferred to a crystallization kettle for reaction at 100-150° C. for 24-48 hours; the precipitate is filtered out, washed, dried, calcined and reduced with hydrogen to obtain the catalyst.

[0021] As a preferred embodiment of the present invention, the amount of urea used is 3-30 times the total molar amount of metals in the soluble salts of copper, zinc and titanium.

[0022] Preferably, the concentration of urea in the mixed solution is, for example, 0.5-10 mol / L.

[0023] As a preferred embodiment of the present invention, the drying conditions are, for example, drying at 60-120° C. for 6-24 hours.

[0024] As a preferred embodiment of the present invention, the calcination conditions are, for example, calcination at 400-600° C. for 3-8 hours in an oxygen-containing atmosphere.

[0025] As a preferred embodiment of the present invention, the conditions for hydrogen reduction are, for example: reduction at 240-260° C. in a 5-40 L / h hydrogen atmosphere for 3-12 h.

[0026] As a preferred embodiment of the present invention, the soluble salt of copper can be selected from one or more of copper nitrate, copper sulfate, copper chloride and copper acetate.

[0027] Preferably, the soluble zinc salt is one or more of zinc nitrate, zinc sulfate, zinc chloride and zinc acetate.

[0028] Preferably, the soluble salt of titanium is one or more of titanium tetrachloride, tetrabutyl titanate, and titanium sulfate.

[0029] The multifunctional copper-based catalyst of the present invention can realize the coupling reaction of n-butanol dehydrogenation, n-butyraldehyde condensation dehydration and octenal hydrogenation, and the consumption of hydrogen in the last step of the coupling reaction further promotes the n-butanol dehydrogenation reaction, thereby improving the n-butanol conversion rate and preparing isooctyl alcohol with high selectivity.

[0030] Compared with the prior art, the beneficial effects of the technical solution of the present invention are mainly reflected in:

[0031] 1) The present invention innovatively utilizes a multifunctional copper-based catalyst to couple the dehydrogenation of n-butanol, the condensation dehydration of n-butyraldehyde, and the hydrogenation of octenal, wherein the hydrogen generated by the dehydrogenation of n-butanol is directly utilized for the hydrogenation of octenal, and n-butanol is directly converted into isooctyl alcohol in the same reactor, thereby saving equipment investment, reducing separation energy consumption, and improving the operating income of the device.

[0032] 2) The bio-based n-butanol raw material used in the present invention is a by-product of the process for preparing bio-based 1,3-butanediol by acetaldehyde condensation hydrogenation, which also improves the profit of the 1,3-butanediol device.

[0033] 3) The present invention utilizes bio-based raw materials to prepare bio-based isooctyl alcohol.

[0034] 4) The isooctyl alcohol prepared by the method of the present invention has a high yield, and the product is easy to separate and purify, and is suitable for industrial production. DETAILED DESCRIPTION

[0035] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0036] The sources of the main raw materials used in the examples are as follows. Unless otherwise specified, other raw materials and reagents can be purchased from commercial sources.

[0037] n-Butanol: ≥99.5%, Wanhua Chemical's self-produced bio-based n-butanol comes from the by-product of the bio-based 1,3-butanediol unit;

[0038] Nitrogen: Dalian Data Gas Co., Ltd.;

[0039] Copper nitrate trihydrate: purity ≥99%, Beijing Inokai Technology Co., Ltd.;

[0040] Copper sulfate pentahydrate: purity ≥99%, Beijing Inokai Technology Co., Ltd.;

[0041] Cupric chloride dihydrate: purity ≥98%, Beijing Inokai Technology Co., Ltd.;

[0042] Copper acetate: purity ≥98%, Beijing Inokai Technology Co., Ltd.;

[0043] Zinc nitrate hexahydrate: purity ≥98%, Beijing Inokai Technology Co., Ltd.

[0044] Zinc sulfate heptahydrate: purity ≥99.5%, Beijing Inokai Technology Co., Ltd.;

[0045] Zinc chloride: purity ≥98%, Beijing Inokai Technology Co., Ltd.;

[0046] Zinc acetate: purity ≥99.5%, Beijing Inokai Technology Co., Ltd.;

[0047] Titanium tetrachloride: purity ≥99%, Beijing Inokai Technology Co., Ltd.;

[0048] Tetrabutyl titanate: purity ≥99%, Beijing Inokai Technology Co., Ltd.;

[0049] Titanium sulfate: purity ≥99%, Beijing Inokai Technology Co., Ltd.

[0050] The reactor in the following examples is a fixed bed reactor, and the fixed bed has an inner diameter of 10 mm and a length of 1000 mm.

[0051] The gas chromatography analysis used in the embodiment of the present invention was carried out according to the following method: 30m DB-WAX, ID.: 0.32mm, FD.: 0.25μm; 80-230°C, 3°C / min, nitrogen flow rate: 30mL / min, hydrogen flow rate: 40mL / min, air flow rate: 400mL / min; injection volume: 0.2μL. GC was tested using Agilent7820, and the sample was diluted 3 times with chromatographic acetonitrile.

[0052] [Catalyst Preparation Example 1]

[0053] 15.10 g of copper nitrate trihydrate, 6.20 g of zinc nitrate hexahydrate, 7.90 g of titanium tetrachloride and 75.08 g of urea were dissolved in 250 g of deionized water, and the mixed solution was transferred to a crystallization kettle and reacted at 130° C. for 36 hours. The precipitate was then filtered out, washed with deionized water and anhydrous ethanol for three times respectively, then dried at 80° C. for 12 hours, and calcined at 500° C. for 5 hours to obtain catalyst 1.

[0054] [Catalyst Preparation Examples 2-6, Comparative Preparation Examples 1-3]

[0055] The catalysts were provided by referring to the method in the above catalyst preparation example 1, except that the catalysts were prepared under different conditions in reference to Table 1. The prepared catalysts were numbered sequentially as catalysts 2-6 and catalysts D1-D3.

[0056] [Example 1]

[0057] Bio-based isooctyl alcohol was prepared as follows:

[0058] 5 g of catalyst 1 was loaded in a fixed bed, and the reactor was operated in a top feeding and bottom discharging manner; catalyst 1 was first reduced at 250°C for 5 h in a 10 L / h hydrogen atmosphere, then switched to a nitrogen atmosphere and cooled to 200°C; then the feed was adjusted to bio-based n-butanol and nitrogen, the n-butanol feed rate was controlled to 5 g / h, the corresponding processing capacity was 1 g n-butanol / (g catalyst*h), the molar ratio of nitrogen to n-butanol was 10:1, the catalyst bed temperature was controlled to 220°C by adjusting the external jacket temperature, and the reaction was carried out under normal pressure; samples were taken during the operation for GC analysis, and the reaction equilibrium was reached after 24 h. The reaction conversion rate was calculated to be 52.3%, and the selectivity was 87.7%.

[0059] [Example 2]

[0060] Bio-based isooctyl alcohol was prepared as follows:

[0061] 5 g of catalyst 2 was loaded in the fixed bed, and the reactor was operated in a top feeding and bottom discharging mode; catalyst 2 was first reduced at 250°C for 5 h in a 10 L / h hydrogen atmosphere, then switched to a nitrogen atmosphere and cooled to 200°C; then the feed was adjusted to bio-based n-butanol and nitrogen, the n-butanol feed rate was controlled to 10 g / h, the corresponding processing capacity was 2 g n-butanol / (g catalyst*h), the molar ratio of nitrogen to n-butanol was 25:1, the catalyst bed temperature was controlled to 260°C, and the reaction equilibrium was reached after 20 h. The calculated reaction conversion rate was 53.6%, and the selectivity was 86.3%.

[0062] [Example 3]

[0063] Bio-based isooctyl alcohol was prepared as follows:

[0064] 5 g of catalyst 3 was loaded in the fixed bed, and the reactor was operated in a top feeding and bottom discharging mode; catalyst 3 was first reduced at 250°C for 5 h in a 10 L / h hydrogen atmosphere, then switched to a nitrogen atmosphere and cooled to 200°C; then the feed was adjusted to bio-based n-butanol and nitrogen, the n-butanol feed rate was controlled to 15 g / h, the corresponding processing capacity was 3 g n-butanol / (g catalyst*h), the molar ratio of nitrogen to n-butanol was 50:1, the catalyst bed temperature was controlled to 280°C, and the reaction equilibrium was reached after 16 h. The calculated reaction conversion rate was 47.2%, and the selectivity was 86.6%.

[0065] [Example 4]

[0066] Bio-based isooctyl alcohol was prepared as follows:

[0067] 5 g of catalyst 4 was loaded in the fixed bed, and the reactor was operated in a top feeding and bottom discharging mode; catalyst 4 was first reduced at 250°C for 5 h in a 10 L / h hydrogen atmosphere, then switched to a nitrogen atmosphere and cooled to 200°C; then the feed was adjusted to bio-based n-butanol and nitrogen, the n-butanol feed rate was controlled to 3 g / h, the corresponding processing amount was 0.6 g n-butanol / (g catalyst*h), the molar ratio of nitrogen to n-butanol was 5:1, the catalyst bed temperature was controlled to 180°C, and the reaction equilibrium was reached after 24 h. The calculated reaction conversion rate was 47.5%, and the selectivity was 88.1%.

[0068] [Example 5]

[0069] Bio-based isooctyl alcohol was prepared as follows:

[0070] 5 g of catalyst 5 was loaded in the fixed bed, and the reactor was operated in a top feeding and bottom discharging mode; the catalyst 5 was first reduced at 250°C for 5 h in a 10 L / h hydrogen atmosphere, and then switched to a nitrogen atmosphere and cooled to 200°C; thereafter, the feed was adjusted to bio-based n-butanol and nitrogen, the n-butanol feed rate was controlled to 0.5 g / h, the corresponding processing amount was 0.1 g n-butanol / (g catalyst*h), the molar ratio of nitrogen to n-butanol was 1:1, the catalyst bed temperature was controlled to 150°C, and the reaction equilibrium was reached after 24 h. The calculated reaction conversion rate was 50.2%, and the selectivity was 85.3%.

[0071] [Example 6]

[0072] Bio-based isooctyl alcohol was prepared as follows:

[0073] 5 g of catalyst 6 was loaded in the fixed bed, and the reactor was operated in a top feeding and bottom discharging mode; the catalyst 6 was first reduced at 250°C for 5 h in a 10 L / h hydrogen atmosphere, and then switched to a nitrogen atmosphere and cooled to 200°C; thereafter, the feed was adjusted to bio-based n-butanol and nitrogen, and the n-butanol feed rate was controlled to 25 g / h, corresponding to a processing capacity of 5 g n-butanol / (g catalyst*h), a nitrogen to n-butanol molar ratio of 10:1, and the catalyst bed temperature was controlled to 300°C. Reaction equilibrium was reached after 16 h, and the reaction conversion rate was calculated to be 42.6%, and the selectivity was 85.9%.

[0074] [Comparative Example 1]

[0075] Bio-based isooctyl alcohol was prepared in substantially the same manner as in Example 1, except that the catalyst loaded in the fixed bed was replaced with catalyst D1.

[0076] After the reaction equilibrium of this comparative example, the calculated reaction conversion rate was 2.6% and the selectivity was 31.7%.

[0077] [Comparative Example 2]

[0078] Bio-based isooctyl alcohol was prepared in substantially the same manner as in Example 1, except that the catalyst loaded in the fixed bed was replaced with catalyst D2.

[0079] After the reaction equilibrium of this comparative example, the calculated reaction conversion rate was 44.0% and the selectivity was 6.4%.

[0080] [Comparative Example 3]

[0081] Bio-based isooctyl alcohol was prepared in substantially the same manner as in Example 1, except that the catalyst loaded in the fixed bed was replaced with catalyst D3.

[0082] After the reaction equilibrium of this comparative example, the calculated reaction conversion rate was 18.8% and the selectivity was 72.5%.

[0083] Table 1. Preparation conditions of different catalysts

[0084]

[0085]

Claims

1. A method for preparing bio-based isooctyl alcohol from n-butanol in one step, characterized in that: The method comprises continuously feeding bio-based n-butanol and nitrogen into a reactor simultaneously, and synthesizing bio-based isooctyl alcohol in one step under the action of a multifunctional copper-based catalyst; The catalyst is calculated based on the total mass as 100%, It includes the following components: Copper 15-60%, zinc oxide 10-45%, titanium dioxide 20-50%.

2. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 1, characterized in that The catalyst is calculated based on the total mass as 100%, It includes the following components: Copper 35-55%, zinc oxide 15-30%, titanium dioxide 30-45%.

3. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 1, characterized in that: The processing amount of the catalyst is 0.1-5 g of bio-based n-butanol / (g catalyst·h).

4. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 3, characterized in that: The processing amount of the catalyst is 0.5-2 g of bio-based n-butanol / (g catalyst·h).

5. The method for preparing bio-based isooctyl alcohol by one-step method of n-butanol according to any one of claims 1 to 4, characterized in that: The molar ratio of nitrogen to bio-based n-butanol is 1-50.

6. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 5, characterized in that: The molar ratio of nitrogen to bio-based n-butanol is 5-25.

7. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to any one of claims 1 to 4, characterized in that: The reaction temperature in the reactor is 150-300°C, and the reaction pressure is normal pressure.

8. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 7, characterized in that: The reaction temperature in the reactor is 180-280°C.

9. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to any one of claims 1 to 4, characterized in that: The catalyst is loaded in a reactor, raw materials of bio-based n-butanol and nitrogen enter from the upper end of the reactor, and the reaction materials flow out from the lower end of the reactor and then undergo gas-liquid separation, and the liquid phase is collected to obtain a reaction liquid containing bio-based isooctyl alcohol.

10. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 9, characterized in that: The reactor is a fixed bed reactor.

11. The method for preparing bio-based isooctyl alcohol by one-step method of n-butanol according to any one of claims 1 to 4, characterized in that: The bio-based n-butanol is derived from a by-product of a process for preparing bio-based 1,3-butanediol by an acetaldehyde condensation hydrogenation method.

12. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to any one of claims 1 to 4, characterized in that: The catalyst is prepared by at least one of a coprecipitation method, a hydrothermal method, an adsorption method, an impregnation method, and a sol-gel method.

13. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 12, characterized in that: The catalyst is prepared by a co-precipitation method.

14. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 12, characterized in that: The preparation method of the catalyst is as follows: Soluble salts of copper, zinc, titanium and urea are dissolved in deionized water, and the mixed solution is transferred to a crystallization kettle for reaction at 100-150° C. for 24-48 hours; the precipitate is filtered out, washed, dried, calcined and reduced with hydrogen to obtain the catalyst.

15. The method for preparing bio-based isooctyl alcohol from n-butanol in one step according to claim 14, characterized in that: The dosage of the urea is 3-30 times the total molar amount of metals in the soluble salts of copper, zinc and titanium.

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