WO2018148939A1

WO2018148939A1 - Reaction catalyst for epimerization of monosaccharides

Info

Publication number: WO2018148939A1
Application number: PCT/CN2017/073962
Authority: WO
Inventors: 张建; 张业新; 张亚杰
Original assignee: 中国科学院宁波材料技术与工程研究所
Priority date: 2017-02-17
Filing date: 2017-02-17
Publication date: 2018-08-23

Abstract

The invention relates to a reaction catalyst for epimerization of monosaccharides, preparation and recovery method thereof. The catalyst is a hydrogel of metal oxide-quantum dots, wherein the metal is selected from the group consisting of molybdenum, tungsten, tin, or combinations thereof. The catalyst has a high utilization rate and good selectivity, and is easy to recover.

Description

Monosaccharide epimerization reaction catalyst

Technical field

The invention belongs to the field of chemical industry, and in particular relates to a monosaccharide epimerization reaction catalyst and a preparation and recovery method thereof.

Background technique

Rare sugars, such as mannose, sucrose, ribose, etc., have important applications in food, pharmaceutical, and clinical medicine, but they are very rare compared to glucose and fructose, which are abundant in nature. The monosaccharide epimerization reaction is an important means for obtaining rare sugars, and the commonly used catalyst is an epimerase. Epimerases are used under harsh conditions (alkaline conditions), sensitive to impurities, narrow reaction temperature window (around 62 ° C), limited by thermodynamic equilibrium, low yield, and the separation and recovery of enzymes is very cumbersome. In contrast, the use of inorganic salt catalysts is relatively broad and can be carried out at higher temperatures (80-150 ° C), resulting in higher yields. Such catalysts can be divided into two classes, homogeneous catalysts and heterogeneous catalysts. The homogeneous catalyst is soluble and can be sufficiently contacted with monosaccharide molecules such as sodium molybdate, ammonium molybdate, and the like. CN102807593A discloses a process for preparing D-mannose, which uses ammonium molybdate to catalyze the epimerization reaction of glucose to obtain mannose. However, such catalysts are difficult to separate and recover, and it is necessary to add a mineral acid to ensure that the reaction is in an acidic environment, which further increases the difficulty of product separation. Another type of catalyst, a heterogeneous catalyst, is insoluble in water and is easily separated from the reaction system, such as molybdenum-based heteropolyacids. CN104004030A discloses a catalyst for the differential production of mannose from glucose, that is, a tungsten-containing compound, including tungsten oxide, tungsten carbide, tungsten nitride, tungsten phosphide, tungsten sulfide, and the like. However, the heterogeneous catalyst can be sufficiently contacted with the monosaccharide molecules by stirring, and the catalyst is used in a large amount and has low efficiency.

In summary, there is still a lack of a monosaccharide epimerization reaction catalyst with high utilization rate, good selectivity and convenient recovery.

Summary of the invention

The invention provides a monosaccharide epimerization reaction catalyst and a preparation method thereof, and a use and recovery method thereof, the catalyst has the advantages of high utilization rate, good selectivity and convenient recovery.

In a first aspect of the invention, there is provided a monosaccharide epimerization reaction catalyst comprising a catalytically effective amount of a metal oxide quantum dot hydrosol, wherein the metal is selected from the group consisting of molybdenum, tungsten , tin, or combination.

In another preferred embodiment, the catalyst is selected from the group consisting of molybdenum oxide quantum dot hydrosols, tungsten oxide quantum dot hydrosols, tin oxide quantum dot hydrosols, or combinations thereof.

In another preferred embodiment, the concentration of the metal oxide quantum dots in the catalyst is from 0.1 to 1 g/L.

In another preferred embodiment, the quantum dots have a size of 1 to 50 nm.

In another preferred embodiment, the quantum dots have a size of 2 to 40 nm.

In another preferred embodiment, the quantum dots have a size of 3-30 nm.

In another preferred embodiment, the method comprises the steps of:

(i) reacting with a simple element of metal and peroxygen to obtain said metal oxide quantum dot hydrosol; wherein said metal is selected from the group consisting of molybdenum, tungsten, tin, or combinations thereof; The ratio of the mass of the metal element to the peroxygen water is from 1 × 10 ^-4 to 1 × 10 ^-3 : 1;

And optional step (ii) preparing said monosaccharide epimerization catalyst using said metal oxide quantum dot hydrosol.

In another preferred embodiment, the mass ratio of the metal element to the peroxygen water is from 1 × 10 ^-3 to 1 × 10 ^-2 : 1 (based on the peroxygen water content in the aqueous solution).

In another preferred embodiment, the metal is a metal elemental powder.

In another preferred embodiment, the peroxygen water is peroxygen water having a mass fraction of 5 to 50%.

In another preferred embodiment, the peroxygen water is peroxygen water having a mass fraction of 10-35%.

In another preferred embodiment, the heating is heating at a reflux temperature.

In another preferred embodiment, the heating temperature is 50 to 150 °C.

In another preferred embodiment, the heating temperature is 80-130 °C.

In another preferred embodiment, the heating time is 1-36 h.

In another preferred embodiment, the heating time is 12-24 h.

According to a second aspect of the present invention, there is provided a process for catalyzing a monosaccharide epimerization reaction, the method comprising the steps of: mixing the catalyst of the first aspect of the invention with a monosaccharide to form an epimerization The catalyst-monosaccharide mixed solution is heated to carry out the reaction; preferably, the heating is carried out by means of microwave irradiation, and/or ultraviolet radiation.

In another preferred embodiment, the mixed solution further comprises a solvent selected from the group consisting of water, DMSO, DMF, Methanol, ethanol, isopropanol, acetic acid, or a combination thereof.

In another preferred embodiment, the monosaccharide is a hexose and/or a pentose.

In another preferred embodiment, the monosaccharide is selected from the group consisting of glucose, mannose, arabinose, ribose, xylose, lyxose, or a combination thereof.

In another preferred embodiment, the reaction is carried out in a closed reactor.

In another preferred embodiment, the epimerization catalyst-monosaccharide mixed solution has a monosaccharide concentration of 20 to 500 g/liter.

In another preferred embodiment, the catalyst (in terms of metal oxide quantum dot mass) and monosaccharide charge ratio is 0.5 x 10 ^-4 -1 x 10 ^-2 :1.

In another preferred embodiment, the mass ratio of the catalyst to the monosaccharide is from 1 × 10 ^{-4 to} 1 × 10 ^-3 : 1.

In another preferred embodiment, the mass ratio of the catalyst to the monosaccharide is 5 × 10 ^{-4 -} 2.5 × 10 ^-3 : 1.

In another preferred embodiment, the reaction temperature is from 50 to 180 °C.

In another preferred embodiment, the temperature of the reaction is from 70 to 140 °C.

In another preferred embodiment, the reaction time is from 0.5 to 10 hours.

In another preferred embodiment, the heating is by microwave radiation.

In another preferred embodiment, the heating is supplemented by ultraviolet light radiation.

In another preferred embodiment, the reaction solution is stirred during the reaction.

In another preferred embodiment, the stirring speed is 0-300 rpm.

In a third aspect of the invention, there is provided a catalyst recovery method, characterized in that the method comprises the steps of: applying a DC electric field to the solution containing the catalyst after the catalytic reaction with the catalyst is completed, driving the catalyst The membrane was filtered through to obtain a recovered catalyst.

In another preferred embodiment, the catalyst catalyzes the monosaccharide epimerization reaction as described above.

In another preferred embodiment, the catalyst is passed through a filter membrane and passed to a new monosaccharide solution.

In another preferred embodiment, the DC electric field has a voltage of 10-100 volts.

In another preferred embodiment, the current density is from 0.01 to 5 amps per square centimeter.

In another preferred embodiment, the filter membrane is selected from the group consisting of a microporous membrane, an ultrafiltration membrane, a nanofiltration membrane, or a combination thereof.

In another preferred embodiment, the filter membrane has a pore diameter of from 2 nm to 450 nm.

It is to be understood that within the scope of the present invention, the various technical features of the present invention and the technical features specifically described in the following (as in the embodiments) may be combined with each other to constitute a new or preferred technical solution. Due to space limitations, we will not repeat them here.

DRAWINGS

1 is a graph showing the yield and selectivity of a glucose epimerization product mannose in Example 1 as a function of reaction temperature;

2 is a schematic view of a preferred catalyst electrophoresis recovery apparatus according to the present invention;

Among them, 1 is a filter membrane, 2 is a monosaccharide solution for catalytic reaction, 3 is a new monosaccharide solution, 4 is a container, 5 is a positive electrode, 6 is a negative electrode, and 7 is a power source.

detailed description

The inventors have conducted long-term and intensive research and found that the use of a metal oxide quantum dot hydrosol catalyst has both high dispersibility of the homogeneous catalyst and separability of the heterogeneous catalyst. Quantum dots can be stably dispersed in an aqueous solution to form a sol, which can fully interact with monosaccharide molecules and improve their utilization. By applying a DC electric field, the recycling of the metal oxide quantum dot catalyst can be realized by electrophoresis, and the recycling of the catalyst can be realized. On the basis of this, the present invention has been completed.

Monosaccharide epimerization reaction catalyst

The present invention provides a monosaccharide epimerization reaction catalyst which is a metal oxide quantum dot hydrosol wherein the metal is selected from the group consisting of molybdenum, tungsten, tin, or combinations thereof.

Preferably, the catalyst is selected from the group consisting of molybdenum oxide quantum dot hydrosols, tungsten oxide quantum dot hydrosols, tin oxide quantum dot hydrosols, or combinations thereof.

Preferably, the quantum dots have a size of from 1 to 50 nanometers. More preferably, the quantum dots have a size of from 3 to 30 nanometers.

Preparation method of monosaccharide epimerization reaction catalyst

The invention provides a preparation method of a monosaccharide epimerization reaction catalyst, the method comprising the steps of:

(i) adding the elemental metal to peroxygen, wherein the metal is selected from the group consisting of molybdenum, tungsten, tin, or combinations thereof;

(ii) heating and cooling.

Among them, the metal element can be added to the peroxygen water in any form, preferably a metal elemental powder. In a preferred embodiment, the peroxygen water is from 5 to 50% by mass of peroxygen water, more preferably from 10 to 35% of peroxygen. The mass ratio of the metal elemental substance to the peroxygen water is not particularly limited, and is preferably 1 × 10 ^-4 to 1 × 10 ^-3 : 1;

The reaction is heated at a temperature of from 50 to 150 ° C, preferably from 80 to 130 ° C, more preferably at a reflux temperature. The reaction time is not particularly limited, and preferably, the heating time is from 1 to 36 h, more preferably from 12 to 24 h.

Method for catalyzing the epimerization reaction of monosaccharides

The present invention provides a method for catalyzing the epimerization reaction of a monosaccharide, the method comprising the steps of: mixing the catalyst of the present invention with a monosaccharide in a solvent, and heating to carry out the reaction. Preferably the solvent is water.

In a preferred embodiment, the monosaccharide is a six carbon sugar and/or a five carbon sugar. More preferably, the monosaccharide is selected from the group consisting of glucose, mannose, arabinose, ribose, xylose, lyxose, or a combination thereof.

The reaction can be carried out in any conventional heating apparatus. Preferably, the reaction is carried out in a closed reactor.

In another preferred embodiment, the catalyst has a monosaccharide concentration of 20-500 g/l after mixing.

Preferably, the mass ratio of the catalyst to the monosaccharide is from 1 × 10 ^{-4 to} 1 × 10 ^-3 . More preferably, the catalyst (in terms of metal oxide quantum dot mass) and monosaccharide charge ratio is 5 x 10 ^{-4 -} 2.5 x 10 ^-3 .

In a preferred embodiment, the reaction has a reaction temperature of from 50 to 180 °C. More preferably, the temperature of the reaction is from 70 to 140 °C. The reaction time is not particularly limited, and a preferred reaction time is from 0.5 to 10 hours, more preferably from 0.5 to 10 hours.

In another preferred embodiment, the reaction solution needs to be stirred during the reaction to promote the reaction. The stirring speed is not particularly limited, and preferably, the stirring speed is 0 to 300 rpm.

After the reaction is completed, the catalyst can be recovered by ultrafiltration or electrosorption/analysis.

Method for recovering monosaccharide epimerization reaction catalyst

The present invention provides a method for recovering a catalyst, the method comprising the steps of: applying a DC electric field to the solution after the catalytic reaction with the catalyst of the present invention is completed, driving the catalyst through the filter membrane.

In a preferred embodiment, the catalyst, after passing through the filter membrane under the action of an electric field, enters a new monosaccharide solution to catalyze the new monosaccharide solution.

The voltage and current of the applied DC electric field are not particularly limited. Preferably, the voltage of the direct current electric field is 10-100 volts. Preferably, the current density is from 0.01 to 5 amps per square centimeter.

The filter membrane is also not particularly limited. The filter membrane can pass through the catalyst without passing through a monosaccharide. Preferably, the filter membrane is selected from the group consisting of a microporous membrane, an ultrafiltration membrane, a nanofiltration membrane, or a combination thereof. A preferred pore size is from 2 nm to 450 nm.

Advantages of the invention:

(1) The monosaccharide epimerization reaction catalyst of the present invention is a quantum dot of a metal oxide which can be stably suspended in an aqueous solution, and has high dispersibility of a homogeneous catalyst and separability of a heterogeneous catalyst. . Quantum dots can be stably dispersed in an aqueous solution to form a sol, which can fully interact with monosaccharide molecules and improve their utilization. In particular, the quantum confinement effect imparts high surface energy to the catalyst and exhibits high catalytic activity. The reaction is carried out in a neutral aqueous solution, without any additives, with a wide temperature operating window and high selectivity.

(2) The catalyst usage amount of the present invention is reduced by an order of magnitude as compared with a general inorganic salt catalyst, and the catalyst/monosaccharide charge ratio of the present invention is generally 0.0001 to 0.01.

(3) Since the quantum dots have a charge in the aqueous solution, generally a negative charge, by applying a direct current electric field, the quantum dots can be driven through the isolation filter to enter a new monosaccharide solution, that is, the metal is electrophoresed. The recycling of the oxide quantum dot catalyst enables the recycling of the catalyst.

The invention is further illustrated by the following specific examples. It is to be understood that the following description is only the most preferred embodiment of the invention and should not be construed as limiting the scope of the invention. On the basis of a full understanding of the present invention, the experimental methods in the following examples which do not specify the specific conditions, generally according to the conventional conditions, or according to the conditions recommended by the manufacturer, those skilled in the art can make non-essential aspects of the technical solution of the present invention. Modifications, such modifications are considered to be included in the scope of the invention.

Example 1

15 g of metal molybdenum powder was dispersed into 30 kg of 15 wt% peroxygen water (mass ratio of molybdenum powder to peroxygen water was 5×10 ⁻⁴ ), heated at 100 ° C for 24 hours under reflux, and cooled to room temperature to obtain molybdenum oxide quantum dot hydrosol. The concentration of molybdenum oxide quantum dots is 959 mg/liter, and the average particle diameter is 3 nm.

1.78 liters of molybdenum oxide quantum dot hydrosol and 2 kg of glucose were simultaneously dispersed into 18.22 liters of water, the glucose concentration was 100 g/liter, and the mass ratio of molybdenum oxide quantum dots to glucose was 8.5×10 ⁻⁴ . The mixed solution was reacted in a closed reaction vessel at a temperature of 80, 90, 100, 110, 120, 130 ° C for 4 hours, and stirred at 50 rpm. After the reaction, the yield and selectivity of the obtained epimer mannose are shown in Figure 1. The mannose yield after 110 °C is above 30%, close to the thermodynamic equilibrium yield, and the range of 90-120 °C is selected. Sex>97%.

The molybdenum oxide quantum dot catalyst was recovered by electrophoretic separation, as shown in FIG. A 1 liter 110 ° C reaction solution (2) was separated from 1 liter of a new glucose solution (concentration 100 g/liter) (3) in the same vessel (4) using a 45 micron microporous membrane (1). Insert the positive electrode (5) and the negative electrode graphite rod (6) into the new glucose solution (3) and the post-reaction glucose solution (2), turn on the power supply (7), and the current density is 0.05 amps/square decimeter, and electrify for 3 hours. The molybdenum oxide quantum dots were sufficiently transferred to a new glucose solution, and then the reaction at 110 ° C was repeated, the yield of mannose was 30%, and the selectivity was 95%.

Example 2

450 ml of the molybdenum oxide quantum dot hydrosol synthesized in Example 1 and 200 g of mannose were simultaneously dispersed into 3.8 liters of water, the mannose concentration was 44 g/liter, and the mass ratio of the molybdenum oxide quantum dots to the mannose was 8.8×10. ^–4 . The mixture was heated in a closed reaction vessel under microwave irradiation and reacted at 110 ° C for 6 hours. The yield of the epimer glucose was 65% and the selectivity was 97%. After recovery by nanofiltration, the above procedure was repeated, and the yield of glucose was 62% and the selectivity was 90%.

Example 3

Take 0.1 g of metal tungsten powder, disperse into 200 g of 25 wt% hydrogen peroxide (tungsten powder and peroxygen water mass ratio 5×10 ^–4 ), heat at 100 ° C for 15 hours, and cool to room temperature to obtain tungsten oxide quantum dot hydrosol. The tungsten oxide quantum dot concentration is 640 mg / liter, and the average particle diameter is 5 nm.

Take 500 ml of tungsten oxide quantum dot hydrosol and 500 g of arabinose, while dispersing into 0.93 liters of water, the arabinose concentration is 520 g/l, and the mass ratio of tungsten oxide quantum dots to arabinose is 6.4×10 ⁻ . The mixed solution was reacted in a closed reactor at 110 ° C for 8 hours. The reaction was carried out in a closed reactor at 120 ° C for 10 hours, and the yield of epimer ribose was 35%, and the selectivity was 80%.

The tungsten oxide quantum dot catalyst was recovered by electrophoretic separation, as shown in FIG. A solution of 1 liter of the 110 ° C reaction solution 2 was separated from 1 liter of a new arabinose solution (concentration 520 g/liter) 3 in the same vessel 4 using a 45 micron microfiltration membrane 1. The positive electrode 5 and the negative electrode graphite rod 6 were inserted into the new glucose solution 3 and the reacted arabinose solution 2, respectively, and the power source 7 was turned on, the current density was 3 amps/dm 2 , and the current was energized for 1 hour to fully transfer the quantum dots to the new glucose. In the solution, the reaction at 110 ° C was repeated, and the yield of ribose was 30%, and the selectivity was 95%.

Example 4

Take 0.05 g of metal tin powder, disperse into 200 g of 35 wt% peroxygen water (Sn powder and peroxygen water mass ratio 2.5×10 ^–4 ), heat at reflux at 100 ° C for 36 hours, and cool to room temperature to obtain tin oxide quantum dot hydrosol. The tin oxide quantum dot concentration is 320 mg/liter, and the average particle diameter is 25 nm.

800 ml of tin oxide quantum dot hydrosol and 100 g of ribose were taken and dispersed in 0.93 liters of water with a ribose concentration of 105 g/l. The mass ratio of tin oxide quantum dots to ribose was 1.28×10 ⁻³ . The mixture was reacted in a closed reactor at 110 ° C for 10 hours, supplemented with 50 watts of ultraviolet radiation (wavelength 400-315 nm). The yield of the epimeric arabinose was 70% and the selectivity was 91%.

Example 5

Take 2 liters of molybdenum oxide quantum dot hydrosol synthesized in Example 1 and 2 kg of xylose, while dispersing into 18 liters of water, the concentration of xylose is 100 g/L, and the mass ratio of molybdenum oxide quantum dots to xylose is 9.6×10 ^{– 4} . The mixture was reacted in a closed reactor at 90 ° C for 0.5 hour, and the yield of the epimer issuose was 35%, and the selectivity was 85%.

Example 6

Take 5 liters of molybdenum oxide quantum dot hydrosol synthesized in Example 1 and 2 kg of threose, and disperse into 15 liters of DMSO, the concentration of xylose is 100 g / liter, and the mass ratio of molybdenum oxide quantum dots to lyxose is 2.4. ×10 ^–3 . The mixture was reacted in a closed reactor at 100 ° C for 1 hour, and the yield of xylose was 58% and the selectivity was 89%.

All documents mentioned in the present application are hereby incorporated by reference in their entirety in their entireties in the the the the the the the the In addition, it should be understood that various modifications and changes may be made by those skilled in the art in the form of the appended claims.

Claims

A monosaccharide epimerization reaction catalyst, characterized in that the catalyst comprises a catalytically effective amount of a metal oxide quantum dot hydrosol, wherein the metal is selected from the group consisting of molybdenum, tungsten, tin, or a combination thereof .
The catalyst of claim 1 wherein said catalyst is selected from the group consisting of molybdenum oxide quantum dot hydrosols, tungsten oxide quantum dot hydrosols, tin oxide quantum dot hydrosols, or combinations thereof.
The catalyst according to claim 1, wherein said metal oxide quantum dots have a concentration of from 0.1 to 1 g/L.
The catalyst of claim 1 wherein said quantum dots have a size of from 1 to 50 nanometers.
A method of preparing a catalyst according to any one of claims 1 to 4, characterized in that the method comprises the steps of:

(i) reacting with a simple element of metal and peroxygen to obtain said metal oxide quantum dot hydrosol; wherein said metal is selected from the group consisting of molybdenum, tungsten, tin, or combinations thereof; The ratio of the mass of the metal element to the peroxygen water is from 1 × 10 -4 to 1 × 10 -3 : 1;

And optional step (ii) preparing said monosaccharide epimerization catalyst using said metal oxide quantum dot hydrosol.
A method for catalyzing a hetero-isomerization reaction of a monosaccharide, characterized in that the method comprises the steps of: mixing the catalyst according to any one of claims 1 to 4 with a monosaccharide to form an epimerization catalyst-single The sugar is mixed and heated to carry out the reaction.
The method of claim 6 wherein said mixed solution further comprises a solvent selected from the group consisting of water, DMSO, DMF, methanol, ethanol, isopropanol, acetic acid, or a combination thereof.
The method of claim 6 wherein said monosaccharide is selected from the group consisting of glucose, mannose, arabinose, ribose, xylose, lyxose, or a combination thereof.
The method according to claim 6, wherein the epimerization catalyst-monosaccharide mixed solution has a monosaccharide concentration of 20 to 500 g/liter.
The method according to claim 6, wherein the catalyst (in terms of metal oxide quantum dot mass) and the monosaccharide are fed at a mass ratio of 0.5 × 10 -4 -1 × 10 -2 :1.
The method according to claim 6, wherein the catalyst to monosaccharide is fed in a mass ratio of from 1 × 10 -4 to 1 × 10 -3 :1.
The method of claim 6 wherein said heating is by microwave radiation and/or ultraviolet radiation.
A catalyst recovery method, characterized in that the method comprises the steps of: after a catalytic reaction with the catalyst is completed, applying a direct current electric field to the solution, driving the catalyst through a filtration membrane to obtain a recovered catalyst.
The method of claim 13 wherein said filter membrane is selected from the group consisting of a microporous membrane, an ultrafiltration membrane, a nanofiltration membrane, or a combination thereof.
The method of claim 13 wherein said filter membrane has a pore size of from 2 nm to 450 nm.