WO2016180000A1

WO2016180000A1 - Two-step ethylene glycol and 1,2-propylene glycol preparation method using cellulose

Info

Publication number: WO2016180000A1
Application number: PCT/CN2015/095076
Authority: WO
Inventors: 王爱琴; 徐刚; 张涛; 郑明远; 庞纪峰; 王�华
Original assignee: 中国科学院大连化学物理研究所
Priority date: 2015-05-13
Filing date: 2015-11-20
Publication date: 2016-11-17
Also published as: CN106278822A; CN106278822B

Abstract

Provided is a two-step ethylene glycol and 1,2-propylene glycol preparation method using cellulose, comprising the following steps: (1) in an alcohol solvent system using cellulose as the raw material, reacting with alcohol under the effect of a first catalyst to produce glycolate and lactate; (2) adding a second catalyst to the mixed liquid product obtained from step (1), and performing hydrogenation by introducing hydrogen so as to obtain ethylene glycol and 1,2-propylene glycol. In the present invention, by means of the two-step reactions performed in alcohol, namely, esterification and hydrogenation, the cellulose conversion rate may reach 100% and the production rate for ethylene glycol and 1,2-propylene glycol may reach 70% or higher while reducing separation cost, thereby providing a new approach to comprehensive and highly effective cellulose usage.

Description

Method for preparing ethylene glycol and 1,2-propanediol by two-step cellulose method

Technical field

The invention relates to the field of cellulose production, in particular to a method for preparing ethylene glycol, 1,2-propanediol by a two-step cellulose method.

Background technique

Biomass is the only renewable organic carbon resource that is ideal for replacing petroleum to produce fuels and chemicals. Therefore, the development of new routes and new methods for biomass conversion to fuels and chemicals is an important goal for the future development of sustainable energy systems. The main part of biomass is cellulose, so the effective use of cellulose has become the focus of research.

Polyols such as ethylene glycol and 1,2-propanediol are important energy liquid fuels, and are also very important polyester raw materials. The industry mainly adopts the petroleum route, that is, ethylene and propylene are epoxidized to obtain ethylene glycol, 1,2- Propylene Glycol [Document 1: He Li, Research Progress in Ethylene Glycol Synthesis Technology, Industrial Catalysis, 2010, 14(6), 11-15. Literature 2: Zheng Jun, 1,2-Propanediol Production Status and Development Prospects at Home and Abroad, Thermosetting Resin, 2009, 24(1), 58-62], the method is technically difficult, low in efficiency, high in energy consumption and serious in pollution. At present, hydrolyzed hydrogenation from biomass is used to prepare ethylene glycol. 1,2-propanediol is regarded as a new utilization route of cellulose conversion. [Documents: 3: A method for preparing ethylene glycol from cellulose, CN101723802A. Document 4: A method for producing ethylene glycol and 1,2-propanediol, CN101768050A. Document 5: tungsten carbide catalyst and its preparation and application in cellulose glycol reaction, CN101648140], this method can not only open up new synthetic routes The product of high economic value obtained from cheap cellulose is realized, and the hydroxyl group of the glucose unit in the cellulose is largely retained during the conversion process, and the atomic economy is high in the whole process, indicating a strong industrial utilization prospect. On the other hand, the intermediate product in the hydrolyzed hydrogenation of cellulose is extremely unstable, which is not conducive to the comprehensive optimization of the series reaction and the adjustment of the catalytic system, and the reaction is carried out in water, and the product separation and solvent recovery cost are high. The method for preparing ethylene glycol and 1,2-propanediol by the two-step cellulose method designed by the invention makes the process step-by-step controllable, the catalyst can be separately recovered, and the recovery cost of the product recovery solvent is low.

Summary of the invention

The object of the present invention is to provide a method for preparing ethylene glycol, 1,2-propanediol from cellulose, firstly converting cellulose into glycolate, lactate, and then hydrogenating to obtain ethylene glycol, 1, 2 - Propylene glycol.

In order to achieve the above object, the technical solution adopted by the present invention is:

In the alcohol solvent system, cellulose is used as a raw material, and reacted with an alcohol at 180-300 ° C for 0.5-3 h under the action of the first catalyst to form a glycolate, a lactate; and a second catalyst is added to the obtained liquid mixed product, and 0.5 is introduced. Hydrogenation of -7 MPa of hydrogen at 140-220 ° C for 0.1-3 h gives a mixture of ethylene glycol and 1,2-propanediol.

The alcohol solvent is at least one of methanol, ethanol, n-propanol or isopropanol. The first catalyst is tungsten oxide, tungsten sulfide, tungsten chloride, tungsten carbide, tungsten hydroxide, tungsten bronze, tungstic acid, tungstate, metatungstic acid, metatungstate, secondary At least one of tungstic acid, paratungstate, peroxo-tungstic acid, peroxytungstate, tungsten-containing heteropolyacid or tungsten-containing heteropolyacid salt. The glycolic acid ester is at least one of methyl glycolate, ethyl glycolate, propyl glycolate or isopropyl glycolate, and the lactate is methyl lactate, ethyl lactate, propyl lactate or isopropyl lactate. At least one of them.

The second catalyst uses silica as a carrier, Cu as an active component or a main active component, and contains Ag, Mg, Ca, Ba, Zn, Zr, Co, Cr, Ni, Mn, Sn, Au, Pt, One or more of Pd, Ru or Re as an auxiliary agent, wherein the mass fraction of Cu is 0.5-40%. The additive mass fraction is 0-5%, and the rest is the carrier.

The alcohol solvent is used in an amount of 10 to 200 times the mass of the cellulose, the first catalyst is used in an amount of 5% to 50% by mass of the cellulose, and the second catalyst is used in an amount of 10 to 40% by mass of the cellulose.

The invention has the following advantages:

1. Compared with the existing cellulose to prepare ethylene glycol, 1,2-propanediol technology, the two-step preparation process of the invention enables the intermediate product to be fixed, and has better stability and controllability.

2. The main active center of the catalyst of the step (2) according to the present invention is Cu, and the catalyst cost is lower than that of the existing noble metals such as Ru and Ni.

3. The alcohol solvent of the present invention has a lower boiling point than the aqueous solvent in the existing hydrolyzed hydrogenation technology, and has lower cost for subsequent product separation and solvent recovery.

The invention is described in detail below by means of specific examples, but these examples are not intended to limit the scope of the invention.

detailed description

Example 1

Preparation of Cs _2.5 H _0.5 PW ₁₂ O ₄₀ Catalyst

Were put 2.5g CS ₂ CO ₃ and the resulting pretreated 18.12g _{_{_{_{H 3 PW 12 O 40 6H 2}}}} 0 0.1mol·L-1 and prepare a solution of 0.08mol·L ^-1, 0.1 · mol·L ^-1 of The Cs ₂ CO ₃ solution was added dropwise to a solution of 0.08 mol·L ^-1 H ₃ PW ₁₂ 0 ₄₀ at a rate of 1 mL·min ^-1 at room temperature. After the completion of the dropwise addition, stirring was continued for 0.5 h, and the mixture was allowed to stand at room temperature for 20 h. Then, the water was slowly evaporated at 323 K to obtain a white solid, which was then dried at about 110 ° C, and calcined at 300 ° C for 2 h before use, and had a specific surface area of 108 m ² g ^-1 .

Example 2

Preparation of W ₂ C/AC: 50 g of activated carbon (AC), 250 mL of 33 wt% HNO _{3 was} weighed, placed in a 500 mL three-necked flask, treated in a water bath at 80 ° C for 24 h, washed to neutral, and dried at 120 ° C for 24 h. 1 g of the pretreated AC was poured into an aqueous solution containing 0.588 g of ammonium metatungstate, and after drying in an oven at 120 ° C, the catalyst precursor was subjected to temperature-programmed reduction in hydrogen, and the specific reaction process was: 8.8 ° C from room temperature. The heating rate of /min was raised to 550 ° C, and then the temperature was raised to 900 ° C at a heating rate of 1 ° C / min for 1 h, and the hydrogen flow rate was 120 mL / min. The theoretical loading of W in the prepared catalyst was 30% by weight.

Example 3

0.3 g of SBA-15 was dispersed in 30 mL of ethanol, 0.13 g of phosphotungstic acid was dissolved in 10 mL of ethanol, and then added dropwise to the above suspension, and the mixture was stirred for 24 hours, and the solvent was evaporated to dryness to prepare a loading amount of 30%. Supported catalyst. The preparation process of SBA-15 is as follows: 2.0 g of P123 is dissolved in 15 mL of water, then 55 mL of hydrochloric acid is added dropwise, the temperature is raised to 40 ° C and stirred for at least 2-3 h, 4.24 g of tetraethyl orthosilicate is added dropwise, and the reaction is carried out at 40 ° C for 24 h. Then, the mixture was transferred to a hydrothermal reaction kettle, allowed to stand at 100 ° C for 24 h, filtered with a sand core funnel, washed with water until neutral, and the remaining solid was first dried at 60 ° C and then placed at 500 ° C for 6 h.

Example 4

7.56 g of Cu(NO ₃ ) ₂ ·3H ₂ O was dissolved in 100 mL of deionized water at room temperature, concentrated aqueous ammonia was added to adjust the pH to 9.0, and 8.0 g of SiO _{2 was} further added. After stirring for 20 min, the mixture was transferred to an ice water bath, and deionized water was added at a rate of 15 mL·min ^-1 with stirring, diluted to 2 L, and filtered. After washing 3 times with deionized water, it was dried overnight at 120 ° C and then calcined at 450 ° C for 4 h. It was reduced at 350 ° C for 3 h before the reaction to obtain 20% Cu/SiO ₂ .

Example 5

1.90 g of Cu(NO ₃ ) ₂ ·3H ₂ O was dissolved in 100 mL of deionized water, and 11 mL of 28 wt.% aqueous ammonia was slowly added dropwise to the solution, followed by stirring at room temperature for 30 min, and 4.0 was added to the above copper ammonia complex solution. g different iron oxide (magnesium oxide, cobalt oxide) and silica ratio carrier, and then vigorously stirred for 2h, the initial pH of the solution = 11-12, and then heated to 90 ° C to evaporate excess ammonia and solvent, so that copper species here During the process, it was deposited on the iron oxide and silica support, and when the solution was neutral, the evaporation was stopped, centrifuged, washed, dried at 120 ° C for 12 h, and then calcined at 450 ° C for 4 h. It was reduced at 350 ° C for 3 h before the reaction. Thus, 5% Fe-15% Cu/SiO ₂ , 5% Mg-15% Cu/SiO ₂ , 5% Co-15% Cu/SiO _{2 were obtained} .

Example 6

Catalytic conversion experiment: 0.5 g of cellulose, 0.2 g of the first catalyst H ₂ WO ₄ , and 50 ml of methanol were placed in a 100 ml reaction vessel, stirred at a speed of 800 rpm, and simultaneously heated to 260 ° C for 2 h. After the reaction was completed, the liquid product and the catalyst were separated by dropping to room temperature and centrifuging at 5000 rpm for 10 minutes. 0.2 g of the second catalyst 20% Cu/SiO _{2 was} added to the liquid product, passed through 3 MPa H ₂ , and heated to 200 ° C for 2 h. After the reaction was completed, the mixture was cooled to room temperature and centrifuged at 5000 rpm for 10 min to separate the liquid product and the catalyst. The liquid product was analyzed using an Agilent 7890B gas chromatograph equipped with a hydrogen flame (FID) detector and an autosampler. HP-INNOWAX capillary column (30m × 250μm × 0.5μm.), the carrier gas is nitrogen, temperature programmed: stay at 45 ° C for 3 min, then rise to 100 ° C at 5 ° C / min, then rise to 250 ° C / 12 °C stay for 3min. The detector temperature was 270 ° C, the hydrogen flow rate was 30 ml/min, the air flow rate was 400 ml/min, and the N ₂ flow rate was 35 ml/min. The inlet temperature was 220 ° C, the injection volume was 1 μl, and the split ratio was 20:1.

The cellulose conversion rate is calculated by:

The formula for calculating the yield of ethanol and n-propanol is as follows (wherein the carbon content of the cellulose in the reactant is determined by an elemental analyzer):

Other liquid products and gaseous products (CO, CO ₂ , CH _{4 ,} etc.) were not calculated for their yield.

Example 7

Replacing the types of the first catalyst and the second catalyst, the other reaction conditions are the same as in Example 6, comparing various types of tungsten-containing catalysts H ₂ WO ₄ , WO ₃ , Na ₂ WO ₄ , AMT, W ₂ C/AC, HPW/SBA- 15, Cs _2.5 H _0.5 PW ₁₂ O ₄₀ and copper-containing catalyst 20% Cu/SiO ₂ , 5% Fe-15% Cu/SiO ₂ , 5% Mg-15% Cu/SiO ₂ , 5% Co-15% Cu The catalytic conversion results of cellulose catalyzed by /SiO ₂ are shown in Table 1.

Table 1 Comparison of cellulose catalytic conversion performance on various catalysts

As shown in the table, cellulose can be converted into ethylene glycol, 1,2-propanediol in high yield on various tungsten-containing and copper-containing catalysts involved in the present invention. Among them, W ₂ C / AC 5% Fe-15% Cu / SiO ₂ can make ethylene glycol, 1,2-propanediol yield of 64.3% and 8.6%.

Example 8

The solvent type was replaced, and other reaction conditions were the same as in Example 6. The results of cellulose catalytic conversion in methanol, ethanol, and n-propanol systems were compared, as shown in Table 2.

Table 2 Comparison of cellulose catalytic conversion performance in various alcohol solvents

As shown in the table, cellulose can be efficiently converted into ethylene glycol, 1,2-propanediol in various alcohol solvents of the present invention.

Example 9

Comparison of catalytic conversion properties of cellulose at different reaction temperatures. See Table 3, except that the reaction temperature is different, the other reaction conditions are the same as in Example 6.

Table 3 Comparison of Catalytic Conversion Properties of Cellulose at Different Reaction Temperatures

As can be seen from the table, the cellulose was catalyzed by H ₂ WO _{4 to} have excellent ethylene glycol, 1,2-propanediol yield in a certain temperature range.

Example 10

Comparison of catalytic conversion properties of cellulose at different reaction times. See Table 4, except that the reaction time is different, the other reaction conditions are the same as in Example 6.

Table 4 Comparison of Catalytic Conversion Properties of Cellulose on H ₂ WO ₄ Catalyst at Different Reaction Time

It can be seen from the table that cellulose has excellent ethylene glycol, 1,2-propanediol yield in a certain time range.

Claims

A method for preparing ethylene glycol and 1,2-propanediol by a two-step cellulose method, comprising the steps of:

(1) adding cellulose to the alcohol solvent, and reacting under the action of the first catalyst;

(2) A second catalyst is added to the mixed product obtained in the step (1), and hydrogen is introduced to carry out a reaction to obtain a mixture of ethylene glycol and 1,2-propylene glycol.
The method according to claim 1, wherein the alcohol solvent in the step (1) is one or more selected from the group consisting of methanol, ethanol, n-propanol or isopropanol.
The method according to claim 1, wherein the first catalyst in the step (1) is an oxide of tungsten, a sulfide of tungsten, a chloride of tungsten, a carbide of tungsten, a hydroxide of tungsten. , tungsten bronze, tungstic acid, tungstate, metatungstic acid, metatungstate, paratungstic acid, paratungstate, peroxytungstic acid, peroxytungstate, tungsten-containing heteropoly acid or tungsten-containing heteropoly One or more of the acid salts.
The method according to claim 1, wherein the second catalyst in the step (2) comprises silica as a carrier, Cu as an active component, and contains Ag, Mg, Ca, Ba, Zn, One or more of Zr, Co, Cr, Ni, Mn, Sn, Au, Pt, Pd, Ru or Re as an auxiliary agent, wherein the mass fraction of Cu is 0.5-40%; the mass fraction of the auxiliary agent is 0. -5%, the rest being the carrier.
The method according to claim 1, wherein the mass of the alcohol solvent in the step (1) is 10 to 200 times the mass of the cellulose, and the mass of the first catalyst is 5% to 50% of the mass of the cellulose. The amount of the second catalyst in the step (2) is 10 to 40% by mass of the cellulose in the step (1).
The method according to claim 1, wherein the reaction in the step (1) is carried out at a reaction temperature of from 180 to 300 ° C and a reaction time of from 0.5 to 3 hours.
The method according to claim 1, wherein the reaction in the step (2) has a reaction temperature of 140 to 220 ° C, a reaction time of 0.5 to 3 hours, and a hydrogen pressure of 0.5 to 7 MPa.