CN101456800A - Novel method for synthesizing acetyl propionyl - Google Patents

Abstract

The invention provides a method for preparing levulinyl, which comprises the following steps: 3-methylbutanol is subjected to molecular rearrangement reaction and oxidation reaction at a reaction temperature of 200-600°C in the presence of oxygen-containing gas to obtain levulinyl acyl products. The preparation method of levulinyl of the present invention can reduce environmental pollution, reduce production cost and can be industrialized.

Description

A new method for the synthesis of levulinyl

technical field

The invention relates to an organic synthesis method, in particular to a preparation method of levulinyl.

Background technique

Levulinyl is an important intermediate in organic synthesis, which can be used to prepare medicines, as raw materials for spices, to prepare essences, and as preservatives and fungicides.

At present, the industrialized production of conventional levulinyl mainly adopts the following methods:

One uses 2-pentanone as a raw material and selenium dioxide as an oxidant to oxidize the methylene group adjacent to the carbonyl group to obtain a finished product. The disadvantage of the above method is that there is a lot of waste water, which is seriously harmful to the environment; in addition, its raw material, that is, the production of 2-pentanone, also pollutes the environment.

There is also a method to prepare levulinyl from 2,3-pentanediol or 2-hydroxy-3-pentanone. The disadvantage of this method is that the cost is high and there are many wastes.

Or another method is to use 3-bromo-2-pentanone as raw material, react with sodium azide to generate azide and then prepare levulinyl. The disadvantage of this method is that the three wastes and corrosion of the bromination reaction are all Very serious, sodium azide itself is a highly toxic drug.

USP2,799,707 discloses a method for synthesizing levulinyl with hydroxyacetone and paraldehyde, but the cost is high and it can only be used as a laboratory preparation method.

U.S. Patent No. 6,720,456 has been improved with a phase transfer catalyst, but the problem has not been fundamentally solved in fact, and the cost and three wastes are still the reasons why it cannot be industrialized.

To sum up, the art lacks a method for preparing levulinyl that can overcome the defects of the prior art such as polluting the environment and high production costs.

Therefore, there is an urgent need in this area to develop a method for preparing levulinyl that reduces environmental pollution, reduces production costs and can be industrialized.

Contents of the invention

The purpose of the present invention is to obtain a kind of levulinyl preparation method that reduces environmental pollution, reduces production cost and can be industrialized.

The present invention provides a kind of method for preparing levulinyl, it comprises the steps:

3-Methylbutanol carries out the molecular rearrangement reaction and oxidation reaction of the following formula (I) in the presence of oxygen-containing gas at a reaction temperature of 200-600° C. to obtain the levulinyl product:

_{2CH3CHCH3CH2CH2OH + 3O2 → 2CH3COCOCH2CH3 + 4H2O} ( _I ) _.

In a specific embodiment of the present invention, the molar ratio of 3-methylbutanol to oxygen-containing gas is 0.5-2.

In a specific embodiment of the present invention, the oxygen-containing gas is oxygen or air.

In a specific embodiment of the present invention, the molecular rearrangement reaction and oxidation reaction of the formula (I) are carried out in the presence of a metal or metal oxide catalyst.

In a specific embodiment of the present invention, the metal or metal oxide catalyst is selected from copper, zinc, aluminum oxide, cobalt oxide, barium oxide or combinations thereof.

In a specific embodiment of the present invention, the composition of described metal or metal oxide catalyst is as follows:

40-48wt% of copper, 2-10wt% of zinc, 15-36wt% of aluminum oxide, 4-8wt% of cobalt oxide and 5-20wt% of barium oxide, calculated by the total weight of the catalyst.

In a specific embodiment of the present invention, the metal or metal oxide catalyst is set as a catalyst layer in a fixed-bed reactor, so that the 3-methylbutanol and oxygen-containing gas are continuously passed through the catalyst layer to carry out The molecular rearrangement reaction and oxidation reaction of the formula (I).

In a specific embodiment of the present invention, the space velocity at which the 3-methylbutanol or the oxygen-containing gas continuously passes through the catalyst layer is 1000˜6000 h ⁻¹ .

In a specific embodiment of the present invention, 3-methylbutanol gas is fed into one end of the fixed-bed reactor, and air or oxygen with a temperature of 200°C to 600°C is fed into the middle of the fixed-bed reactor. .

In a specific embodiment of the present invention, also comprise the recycling step of described 3-methyl butanol, described step is as follows:

The obtained levulinyl product is separated to obtain purified levulinyl and 3-methyl butanol, and the 3-methyl butanol is recovered as a raw material.

Detailed ways

After extensive and in-depth research, the inventor found that 3-methylbutanol was oxidized and molecularly rearranged at a specific temperature to obtain levulinyl by improving the preparation process, thereby obtaining a cheap 3- A method for preparing levulinyl from methyl butanol, which is particularly excellent in terms of environmental protection, cost and industrialization, and is particularly suitable as a large-scale industrial production method of levulinyl. The present invention has been accomplished on this basis.

Principle of the present invention is as follows:

Using cheap 3-methylbutanol as raw material, after heating and gasification (preferably through copper, zinc and other metals and aluminum oxide, cobalt oxide, barium oxide and other catalyst layers) molecular rearrangement reaction and reaction with oxygen or air Oxygen undergoes an oxidation reaction to obtain levulinyl. The reactant is refined to obtain the finished product of levulinyl with a purity of more than 98%. The reaction formula is as follows:

2CH ₃ CHCH ₃ CH ₂ CH ₂ OH+3O ₂ →2CH ₃ COCOCH ₂ CH ₃ +4H ₂ O (I)

The side reaction of the above reaction is that the 3-methylbutanol will be oxidized and converted into butanone. The inventors also found that the selectivity of 3-methylbutanol to levulinyl is higher at a specific temperature.

Various aspects of the present invention are described in detail below:

A kind of method for preparing levulinyl of the present invention, it comprises the steps:

3-Methylbutanol undergoes molecular rearrangement and oxidation reactions at a reaction temperature of 200-600°C in the presence of oxygen-containing gas to obtain levulinyl products.

The reaction formula is as follows:

2CH ₃ CHCH ₃ CH ₂ CH ₂ OH+3O ₂ →2CH ₃ COCOCH ₂ CH ₃ +4H ₂ O (I)

The 3-methylbutanol can be obtained commercially. The concentration of the 3-methylbutanol is not lower than 95% by weight.

From an economic point of view, usually the oxygen-containing gas is oxygen or air. Other inert gases containing oxygen may also be used in the present invention.

Preferably, the molecular rearrangement reaction and oxidation reaction of the formula (I) are carried out in the presence of a metal or metal oxide catalyst.

The catalyst is selected from catalysts that can promote the molecular rearrangement reaction and oxidation reaction of 3-methylbutanol and oxygen-containing gas. Typically, the molecular rearrangement and oxidation reactions are carried out in the presence of metal or metal oxide catalysts. Preferably, the metal or metal oxide catalyst is selected from copper, zinc, aluminum oxide, cobalt oxide, barium oxide or combinations thereof. More preferably, the composition of the metal or metal oxide catalyst is as follows: copper 40-48wt%, zinc 2-10wt%, aluminum oxide 15-35wt%, cobalt oxide 4-8wt%, barium oxide 5-20wt%.

The catalyst of the present invention can be prepared by common technical means, for example: the metal catalyst is obtained by preparing the metal mixture (for example, in the form of an alloy) into particles, nets or sponges, and the metal oxide catalyst is prepared by impregnation method Or obtained by co-precipitation method. Specific examples include, but are not limited to, the metal catalyst is a networked copper and zinc alloy (that is, a brass alloy), and the metal oxidant catalyst is mixed at 600° C. obtained by sintering under the conditions.

The reaction temperature is usually selected at 200-600° C., so that 3-methylbutanol and oxygen-containing gas undergo molecular rearrangement and oxidation reactions. Preferably, the temperature range is between 300°C and 500°C.

The molar ratio of the 3-methylbutanol to oxygen in the oxygen-containing gas may be 0.5-2, preferably 0.7-1.5.

In order to be more suitable for industrialized production, the metal or metal oxide catalyst can be set as a catalyst layer in a fixed bed reactor, and the 3-methylbutanol and oxygen-containing gas are continuously passed through the catalyst layer to carry out the molecular weight exhaustion and oxidation reactions.

Usually, in the fixed bed, the space velocity of the total material such as 3-methylbutanol or oxygen-containing gas is 1000-6000h ^-1 .

In order to better achieve the purpose of environmental protection, the step of recycling and using the 3-methylbutanol is also included, and the steps are as follows:

The obtained levulinyl product is separated to obtain purified levulinyl and 3-methyl butanol, and the 3-methyl butanol is recovered as a raw material.

The optimized technical scheme of the present invention is as follows:

The vaporized 3-methyl butanol with a content of more than 95% is reacted with oxygen or air continuously through a fixed-bed reactor provided with a catalyst. The reaction temperature is 200-600°C. 3-methyl butanol and The molar ratio of oxygen or oxygen in air is 0.5-2.

Said catalyst is copper, zinc and other metals and aluminum oxide, cobalt oxide, barium oxide and other metal oxides; by copper 40 ~ 48wt%, zinc 2 ~ 10wt%, aluminum oxide 15 ~ 35wt%, cobalt oxide 4 ~ 8wt% , barium oxide 5 ~ 20wt% composition.

The space velocity of the reaction process is 1000～6000h ^-1 ;

3-methylbutanol gas is fed into one end of the fixed bed reactor, and air with a temperature of 200°C to 600°C is fed into the middle of the reactor;

After the reaction is finished, levulinyl is collected from the reaction product by a conventional method; 3-methylbutanol in the obtained product is recovered for recycling.

The main advantages of the present invention are as follows:

(1) The present invention takes 3-methylbutanol in cheap fusel oil as raw material, after heating and vaporizing, allow it to pass through the catalyst layer of metal oxides such as metals such as copper and zinc and aluminum oxide, cobalt oxide, barium oxide, Oxidation reaction and molecular rearrangement reaction occur under certain temperature conditions to obtain levulinyl. The reaction product is refined to obtain the finished levulinyl product with a purity of more than 98%. Due to the continuous operation of the invention, low raw material price and basically no three wastes, the invention has the characteristics of simple technological process and low production cost.

The compounds provided by the present invention can be synthesized by commercially available raw materials and traditional chemical transformation methods. For example, 3-methylbutanol can be purchased commercially or extracted from fusel oil.

The above-mentioned synthetic method is only the synthetic route of some compounds of the present invention. According to the above-mentioned examples, those skilled in the art can synthesize other compounds of the present invention by adjusting different methods, or those skilled in the art can synthesize the compounds of the present invention according to existing known techniques. compound. The synthesized compound can be further purified by methods such as rectification and crystallization.

Other aspects of the invention will be apparent to those skilled in the art from the disclosure herein.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods without specific conditions indicated in the following examples are usually carried out according to conventional conditions, or according to the conditions suggested by the manufacturer. All parts are by weight and all percentages are by weight unless otherwise indicated.

Unless otherwise defined or stated, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described can be applied to the method of the present invention.

Example 1

Catalyst preparation:

The catalyst bed layer is obtained as follows: add copper, zinc metal and aluminum oxide, cobalt oxide, barium oxide metal oxide catalyst in a diameter 25mm inverted U-shaped fixed-bed reactor, the composition of the catalyst is as follows: by copper 40wt% , zinc 10wt%, aluminum oxide 30wt%, cobalt oxide 6wt%, barium oxide 14wt%. The preparation method of described catalyzer is as follows: Copper and zinc use the 80 order brass nets (wherein the ratio of copper and zinc is 4:1) that Zhangjiagang Hexing silk screen factory produces, then aluminum oxide, cobalt oxide, oxide Barium and the brass mesh were placed in the inverted U-shaped fixed-bed reactor with a diameter of 25 mm.

The outer layer of the reactor is heated by an electric heating wire, and the temperature is controlled by a voltage regulator at 180-450°C. The 3-methylbutanol is gasified at a controlled temperature of 250°C, and air at 350°C is introduced into the middle of the inverted U-shaped reactor, and the space velocity of the reactants is 2000h ^-1 , the moles of 3-methylbutanol and oxygen The ratio is 0.9.

Since it is a continuous production, the yield is calculated as follows: the product is collected at the end of the reactor for 1 hour to obtain the product. The product weighed 112 grams. The product was analyzed by chromatography-mass spectrometry, and contained 33 wt% of 3-methyl butanol and 19 wt% of butanone. Wherein the content of levulinyl is 48wt%. Therefore, the primary reaction yield of levulinyl reaches 23wt%.

The product was rectified to obtain 53 grams of levulinyl product, 21 grams of butanone by-product and 36 grams of raw material 3-methylbutanol. The raw material 3-methyl butanol is recycled for use.

Example 2

Embodiment 2 is the same as the method of embodiment 1, the difference is:

In the preparation process of the catalyst, add the catalyst of copper, zinc and aluminum oxide, cobalt oxide, barium oxide metal oxide in the inverted U-type fixed-bed reactor of diameter 20mm, by copper 45wt%, zinc 5wt% and aluminum oxide 36wt%, Composed of 5wt% cobalt oxide and 9wt% barium oxide.

The vaporization temperature of 3-methylbutanol is 275°C. Air at 300°C was introduced into the middle of the inverted U-shaped reactor, the space velocity of the reactants was 2500h ^-1 , and the molar ratio of 3-methylbutanol to oxygen was 1.1.

The yield of one reaction to obtain levulinyl was 28%.

Example 3

Embodiment 3 is the same as the method of embodiment 1, the difference is:

In the preparation process of the catalyst, add the catalyst of copper, zinc and aluminum oxide, cobalt oxide, barium oxide metal oxide in the inverted U-type fixed-bed reactor of diameter 20mm, by copper 48wt%, zinc 10wt% and aluminum oxide 16wt%, Composed of 8wt% cobalt oxide and 18wt% barium oxide.

The vaporization temperature of 3-methylbutanol is 300°C. Air at 480°C was introduced into the middle of the inverted U-shaped reactor, the space velocity of the reactants was 2500h ^-1 , and the molar ratio of 3-methylbutanol to oxygen was 1.1.

The yield of one reaction to obtain levulinyl was 26%.

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (10)

1. A method for preparing levulinyl, which comprises the steps of: 3-Methylbutanol carries out the molecular rearrangement reaction and oxidation reaction of the following formula (I) in the presence of oxygen-containing gas at a reaction temperature of 200-600° C. to obtain the levulinyl product: _{2CH3CHCH3CH2CH2OH + 3O2 → 2CH3COCOCH2CH3 + 4H2O} ( _I ) _. 2. The method according to claim 1, characterized in that the molar ratio of 3-methylbutanol to oxygen-containing gas is 0.5-2. 3. The method according to claim 1, wherein the oxygen-containing gas is oxygen or air. 4. The method according to claim 1, characterized in that the molecular rearrangement reaction and oxidation reaction of the formula (I) are carried out in the presence of a metal or metal oxide catalyst. 5. The method of claim 4, wherein the metal or metal oxide catalyst is selected from copper, zinc, aluminum oxide, cobalt oxide, barium oxide or combinations thereof. 6. method as claimed in claim 4, is characterized in that, the composition of described metal or metal oxide catalyst is as follows: 40-48wt% of copper, 2-10wt% of zinc, 15-36wt% of aluminum oxide, 4-8wt% of cobalt oxide and 5-20wt% of barium oxide, calculated by the total weight of the catalyst. 7. The method according to claim 4, characterized in that, the metal or metal oxide catalyst is arranged as a catalyst layer in a fixed-bed reactor, so that the 3-methylbutanol and oxygen-containing gas are continuously passed through the The catalyst layer is used to carry out the molecular rearrangement reaction and oxidation reaction of the formula (I). 8 . The method according to claim 7 , wherein the space velocity of the 3-methylbutanol or the oxygen-containing gas continuously passing through the catalyst layer is 1000˜6000 h ⁻¹ . 9. The method according to claim 7, characterized in that 3-methylbutanol gas is introduced at one end of the fixed-bed reactor, and the temperature at the middle of the fixed-bed reactor is 200° C. to 600° C. ℃ air or oxygen. 10. method as claimed in claim 1, is characterized in that, also comprises the recycling step of described 3-methyl butanol, and described step is as follows: The obtained levulinyl product is separated to obtain purified levulinyl and 3-methyl butanol, and the 3-methyl butanol is recovered as a raw material.