CN108101752B

CN108101752B - Method for preparing 1,1,2-trimethoxyethane from biomass

Info

Publication number: CN108101752B
Application number: CN201611042768.0A
Authority: CN
Inventors: 王爱琴; 徐刚; 张涛; 郑明远; 庞纪峰; 王�华
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2016-11-24
Filing date: 2016-11-24
Publication date: 2021-05-04
Anticipated expiration: 2036-11-24
Also published as: CN108101752A

Abstract

The invention provides a method for preparing 1,1,2-trimethoxyethane from biomass including cellulose, starch, hemicellulose, cane sugar, glucose, fructose, fructan, xylose, soluble xylo-oligosaccharide and natural wood fiber raw materials containing carbohydrate components. The method takes renewable natural biomass as a reaction raw material, takes one or more than two of tungsten oxide, tungsten sulfide, tungsten chloride, tungsten carbide, tungsten hydroxide, tungsten bronze, tungstic acid, tungstate-containing salt, metatungstic acid, metatungstate, paratungstic acid, paratungstate, peroxytungstic acid, peroxytungstate, heteropoly tungstic acid and heteropoly tungstic acid-containing salt as a catalyst, and realizes high selectivity of carbohydrate through a one-step catalytic conversion process in a methanol solvent. The reaction provided by the invention not only takes renewable resources as raw materials, but also has the advantages of simple reaction process, high yield of target products, simple, convenient and easy preparation process of the catalyst and low cost.

Description

Method for preparing 1,1,2-trimethoxyethane from biomass

Technical Field

The invention relates to a preparation method of 1,1,2-trimethoxy ethane, in particular to a method for preparing 1,1,2-trimethoxy ethane by one-step catalysis of biomass in methanol solution through a tungsten-containing catalyst

Background

1,1,2-trimethoxy ethane is also called methoxy acetaldehyde dimethyl acetal, is an important chemical intermediate, is widely applied to many fields such as chemical industry, medicine, spice and the like, can be used for preparing polyacetal resin and alkyl vinyl ether, is also an important fuel additive, and can effectively reduce the particle size of emissions when being used as a diesel oil oxygen-containing additive.

Currently, 1,2-trimethoxyethane is mainly obtained by condensation, chlorination and etherification of acetaldehyde, i.e. by further reaction of acetaldehyde with an intermediate product, namely chloracetaldehyde dimethanol, sodium methoxide (potassium) and the like (document 1:1, 1,2-trimethoxyethane and methyl ortho-chloro-from 1-chloro-2,2-dimethoxyethane and/or 1,1-dichloro-2-methoxy, Patent No. DE 2048272-A). The method uses chlorine, lime and the like, has great harm to the environment and is difficult to separate and purify. In addition, the biggest disadvantage of the method is that acetaldehyde is used as raw material and has the following problems: 1. the boiling point is lower (20.8 ℃); 2. is toxic; 3. easily self-polymerize to form paraldehyde and thus are not easy to store for a long time.

The 1,1,2-trimethoxy ethane is prepared by utilizing renewable biomass resources, so that the dependence of human on fossil resources can be reduced, and the environment-friendly and economic sustainable development can be realized. Polyhydroxy compounds, including cellulose, starch, hemicellulose, sucrose, glucose, fructose, fructan, xylose, soluble xylo-oligosaccharides, are widely found in nature. With the development of agricultural technologies, the yield thereof is increasing. The development of renewable biomass for preparing 1,1,2-trimethoxy ethane can partially reduce the dependence on petroleum resources, overcome the defects of the prior art and simultaneously contribute to the realization of deep processing of agricultural products for preparing high-added-value chemicals. From the research results of the current literature, no report exists on the preparation of 1,1,2-trimethoxyethane by using biomass as a raw material and performing high-efficiency and high-selectivity catalytic degradation.

Disclosure of Invention

The invention aims to provide a catalytic conversion method, by which biomass (comprising cellulose, starch, hemicellulose, cane sugar, glucose, fructose, fructan, xylose, soluble xylo-oligosaccharide and natural wood fiber raw materials containing the carbohydrate) can be subjected to catalytic reaction, and 1,1,2-trimethoxyethane can be prepared by a one-pot method with high yield and high selectivity.

In order to achieve the purpose, the invention adopts the technical scheme that: the method is characterized in that biomass, which comprises cellulose, starch, hemicellulose, cane sugar, glucose, fructose, fructan, xylose, soluble xylo-oligosaccharide and natural wood fiber raw materials containing the carbohydrate, are used as reaction raw materials, methanol is used as a solvent, catalytic reaction is carried out in a closed high-pressure reaction kettle, and a catalyst is one or more than two of tungsten oxide, tungsten sulfide, tungsten chloride, tungsten carbide, tungsten hydroxide, tungsten bronze, tungstic acid, tungstate containing salts, metatungstic acid, metatungstate, paratungstate, peroxytungstic acid, peroxytungstate, heteropoly acid containing tungsten and heteropoly acid containing tungsten. The reaction is carried out in a closed autoclave, the reaction temperature is 100-400 ℃, the preferred reaction temperature is 180-300 ℃, the reaction time is not less than 0.5 min, and the preferred reaction time is 0.1-5 h. The reaction pressure is 0.2-20 MPa; the reaction atmosphere can be pure oxygen or air; or inert atmosphere such as nitrogen, argon, helium; or reducing atmosphere hydrogen, preferably the reaction atmosphere is inert atmosphere or air atmosphere. The mass ratio of biomass to methanol is 1:200-1:1, preferably 1:100-1: 10. The amount of the active component tungsten metal in the catalyst is 0.05-50%, preferably 5-15% of the mass of the biomass of the reaction raw material.

The invention has the following advantages:

1. the method is characterized in that 1,1,2-trimethoxyethane is prepared by taking renewable biomass (comprising cellulose, starch, hemicellulose, sucrose, glucose, fructose, fructan, xylose, soluble xylo-oligosaccharide and natural wood fiber raw materials containing the carbohydrates) as a reaction raw material, and compared with acetaldehyde, chlorine and lime used in the existing industrial synthetic route of the 1,1,2-trimethoxyethane, the method has the advantages of cleanness and reproducibility and meets the requirements of sustainable development.

2. The tungsten-based catalyst used is simple and easy to obtain, is convenient to separate, has good catalytic cycle performance, and has good industrial application prospect.

The reaction provided by the invention not only takes renewable resources as raw materials, but also has the advantages of simple reaction process, high yield of target products, simple, convenient and easy preparation process of the catalyst and low cost.

The present invention will be described in detail with reference to specific examples, which are not intended to limit the scope of the present invention.

Detailed Description

Example 1

WO_xPreparation of the catalyst: take 3g WCl₆Dissolved in 100mL of absolute ethanol, the resulting yellow solution was transferred to a Teflon kettle and allowed to stand in an oven at 160 ℃ for 36 h. Naturally cooling to room temperature, suction filtering the formed blue flocculent substance with ethanol-water, washing for 3 times, and drying at 50 deg.C to obtain WO_x。

Example 2

W₂Preparation of C/AC: 50g of Activated Carbon (AC) and 250mL of 33 wt% HNO₃Adding the solution into a 500mL three-neck flask, treating in a water bath at 80 ℃ for 24h, washing to be neutral, and drying at 120 ℃ for 24h to obtain the pretreated AC. Pouring 1g of the pretreated AC into 1.5ml of aqueous solution containing 0.588g of ammonium metatungstate, drying the solution in a 120 ℃ oven, and then carrying out temperature programming reduction on the catalyst precursor in hydrogen: raising the temperature from room temperature to 550 ℃ at the heating rate of 8.8 ℃/min, then raising the temperature to 900 ℃ at the heating rate of 1 ℃/min, and keeping the temperature for 1h, wherein the hydrogen flow rate is 120 mL/min. After reduction, 1% (v/v) O is used₂/N₂The mixed gas is passivated for 6h, and the flow rate is 20 mL/min. The theoretical loading of W in the prepared catalyst was 30 wt%.

Example 3

W₂Preparation of N/AC: the procedure is analogous to example 2, except that hydrogen is replaced by nitrogen and the nitriding temperature is 700 ℃.

Example 4

W₂C/CMK-3 preparation: the procedure was similar to example 2, except that the AC support was replaced with CMK-3. The preparation process of the CMK-3 comprises the following steps: dissolving 1.25g of sucrose in 5g of deionized water, adding 0.14g of concentrated sulfuric acid, adding 1g of SBA-15 into the obtained mixed solution, soaking at room temperature for 6h, and drying at 100 ℃ and 160 ℃ for 6h respectively. The resulting grayish brown powder was again immersed in a solution consisting of 0.8g of sucrose, 0.09g of concentrated sulfuric acid and 5g of deionized water, and the drying step was repeated. Transferring into a tube furnace, keeping the temperature of 900 ℃ for 6h under the nitrogen atmosphere, and completely carbonizing the sucrose. To the resulting black powder was added 50ml of 4 wt% hydrofluoric acid, stirred at room temperature for 2h, filtered/washed, this process was repeated three times to completely remove the silica, and finally in an oven at 120 deg.CDrying overnight to obtain the ordered mesoporous carbon CMK-3.

Example 5

Catalytic conversion experiments: 0.5g of cellulose, 0.1gWO_xAnd 50ml of methanol were added to a 100ml reaction vessel in the atmosphere of atmospheric air, and the reaction was carried out while stirring at 800rpm, and while raising the temperature to 240 ℃ for 1 hour. After the reaction is finished, cooling to room temperature, centrifugally separating the liquid product from the catalyst, and analyzing the liquid product by adopting gas chromatography. The yield of the product was (moles of carbon from carbohydrate in the product)/(total moles of carbon in carbohydrate) x 100%, where only 1,1,2-trimethoxyethane, the target product, was calculated.

Example 6

The kinds of the substitution catalysts and the reaction conditions were the same as in example 5, and the types of tungsten-containing catalysts H were compared₂WO₄，WO₃，Na₂WO₄,AMT,W₂N/AC,W₂C/AC,W₂C/CMK-3,H₃O₄₀PW₁₂,H₃O₄₀SiW₁₂,WO_xThe results of catalytic conversion of cellulose under catalysis are shown in Table 1.

TABLE 1 comparison of catalytic conversion Performance of cellulose over various catalysts

Catalyst and process for preparing same	Conversion (%)	Yield (%)
			H₂WO₄	100	28.7
WO₃	37	21.3
			Na₂WO₄	27	17.5
AMT	49	25.6
			W₂N/AC	67	17.3
W₂C/AC	73	16.7
			W₂C/CMK-3	75	18.8
H₃O₄₀PW₁₂	100	29.0
			H₃O₄₀SiW₁₂	100	24.3
WO_x	100	32.8

As shown in the table, cellulose can be converted to 1,1,2-trimethoxyethane in high yield over various tungsten-containing catalysts involved in the present invention, wherein, WO_xThe yield on the catalyst can reach 32.8 percent.

Example 7

In place of biomass species, the reaction conditions were the same as in example 5, and the catalytic conversion results of cellulose, cellobiose, glucose, starch, birch, miscanthus and cornstalk were compared, as shown in Table 2.

TABLE 2 comparison of catalytic conversion Performance of various biomasses

As shown in the table, various biomasses can be effectively converted into the 1,1,2-trimethoxyethane in the tungsten-containing catalytic system related to the invention.

Example 8

WO at different reaction temperatures_xThe catalytic conversion of cellulose over the catalyst was compared and is shown in Table 3. The reaction conditions were the same as in example 5 except that the reaction temperature was changed.

TABLE 3 comparison of the catalytic conversion of cellulose on WOx catalysts at different reaction temperatures

Temperature of	Conversion rate%	Yield of 1,1,2-trimethoxyethane
			140	21	9.9
180	36	25.4
			220	84	29.1
240	100	32.8
			260	100	28.0
280	100	21.7

As can be seen from the table, the cellulose is in WO in a certain temperature range_xThe catalyst has good yield of 1,1,2-trimethoxy ethane, and the preferred temperature is about 180 ℃ and 260 ℃.

Example 9

WO at different reaction times_xA comparison of the catalytic conversion performance of the cellulose over the catalyst is shown in Table 4. The reaction conditions were the same as in example 5 except that the reaction time was varied.

TABLE 4 WO at different reaction times_xComparison of cellulose catalytic conversion Performance on catalyst

As can be seen from the table, the WO was used over a certain time range_xThe catalytic cellulose has excellent yield of 1,1,2-trimethoxy ethane, and the preferred temperature is 1-5 h.

Example 10

A comparison of the catalytic conversion performance of cellulose on WOx catalyst in different reaction atmospheres is shown in Table 5. The reaction conditions were the same as in example 5 except that the reaction atmosphere was varied.

TABLE 5 WO under different reaction atmospheres_xComparison of cellulose catalytic conversion Performance on catalyst

Atmosphere(s)	Conversion rate%	Yield of 1,1,2-trimethoxyethane
			0.1MPa of air	100	32.8
1MPa of air	100	29.4
			1MPa N₂	100	34.9
1MPa Ar	100	33.0
			1MPa O₂	100	6.5
2MPa O₂	100	2.7

As can be seen from the table, under different reaction atmospheres, with WO_xThe catalytic cellulose has better yield of 1,1,2-trimethoxy ethane, and the inert atmosphere or the atmospheric air atmosphere is more favorable for generating the 1,1,2-trimethoxy ethane.

Claims

1. A method for preparing 1,1,2-trimethoxy ethane by biomass is characterized in that: performing catalytic reaction in a closed high-pressure reaction kettle by using biomass as a reaction raw material, methanol as a solvent and a tungsten-containing compound as a catalyst to obtain a product 1,1, 2-trimethoxyethane; the tungsten-containing compound is one or more of tungsten oxide, tungsten sulfide, tungsten chloride, tungsten carbide, tungsten hydroxide, tungsten bronze, tungstic acid, tungstate-containing salt, metatungstic acid, metatungstate, paratungstic acid, paratungstate, peroxytungstic acid, peroxytungstate, heteropoly tungstic acid and heteropoly tungstic acid-containing salt;

the reaction pressure is 0.1-20 MPa; the reaction atmosphere is one or more than two of inert atmosphere or air atmosphere; the inert atmosphere is one or more than two of nitrogen, argon and helium; the biomass is one or more of cellulose, starch, hemicellulose, sucrose, glucose, mannose, arabinose, galactose, fructose, levan, xylose and soluble xylooligosaccharide, or the chemical formula can be expressed as C_n(H₂O)_mThe compound, n and m are integers of 5 or more.

2. The method of claim 1, wherein: the reaction temperature is 100 ℃ and 400 ℃, and the reaction time is not less than 0.5 minute.

3. The method of claim 1, wherein: the reaction temperature is 180 ℃ and 300 ℃, and the reaction time is 0.1-5 h.

4. The method of claim 1, wherein: the mass ratio of the biomass to the methanol is 1:200-1:1, and the amount of the tungsten metal serving as an active component in the catalyst is 0.05-50% of the mass of the biomass serving as a reaction raw material.

5. The method of claim 1 or 4, wherein: the mass ratio of the biomass to the methanol is 1:100-1:10, and the amount of the tungsten metal serving as an active component in the catalyst is 5-15% of the mass of the biomass serving as a reaction raw material.