CN110743580A - Catalyst for dehydration of 2,3-butanediol to produce methyl ethyl ketone and preparation method thereof - Google Patents

Abstract

A catalyst for efficient dehydration of 2,3-butanediol to prepare methyl ethyl ketone and its preparation method Abstract: The present invention discloses a catalyst for dehydration of 2,3-butanediol to prepare methyl ethyl ketone and a preparation method thereof. The catalyst uses the alkaline earth metal salt barium phosphate as the active component for the first time, and uses the activated carbon as the carrier, and the loading amount is 2% to 10%, preferably 8%. dehydration reaction. The catalyst of the invention has simple preparation process, low preparation cost, high catalytic activity, good stability, environmental protection, and can be recycled. The results show that the conversion rate of 2,3-butanediol is 100.0%, and the yield of methyl ethyl ketone can reach 95.2%. %.

Description

Catalyst for dehydration of 2,3-butanediol to produce methyl ethyl ketone and preparation method thereof

technical field

The invention relates to a catalyst, a preparation method and application, and belongs to the technical field of chemical industry.

Background technique

Methyl ethyl ketone is a widely used organic solvent, many polymer compounds, such as digested cellulose, vinyl resin, polyurethane, magnetic tape, coatings, adhesives, inks, pharmaceutical production and lubricating oil dewaxing, etc. are very useful in methyl ethyl ketone. good solubility. At the same time, methyl ethyl ketone contains carbonyl functional groups, which can be used as raw materials for the production of fragrances, tapes, adhesives, synthetic leather and other products. In addition, it can also be seen in industrial fields such as the preparation of catalysts, antioxidants and corrosion inhibitors. At present, the production methods of methyl ethyl ketone mainly include n-butene two-step method, n-butane liquid-phase oxidation method, butene liquid-phase oxidation method, butadiene catalytic hydrolysis method, isobutylbenzene method, isobutyraldehyde isomerization method, There are more than ten kinds of mixed C4 hydrocarbon oxidation method and biological fermentation method, among which n-butane liquid-phase oxidation method, n-butene method and i-butylbenzene method are the most commonly used. In recent years, the n-butene method is mainly used in the industrialized production of methyl ethyl ketone at home and abroad, but the process is complicated in operation, serious in pollution, and the raw materials come from non-renewable fossil resources, which limit its large-scale development. Combined with today's pursuit of energy conservation and green technology, it is particularly important to explore and develop an environmentally friendly and efficient production process route for methyl ethyl ketone.

With the decrease of fossil resources, the biological fermentation process has gradually matured and attracted the attention of scientific researchers. The technical route of converting biomass resources into high-value derivative chemicals can reduce the consumption and dependence on traditional fossil resources. 2,3-Butanediol is a bio-based platform compound with a wide range of sources and low cost. Therefore, the process of catalyzing the dehydration of 2,3-butanediol to prepare methyl ethyl ketone has become the research focus and work focus of domestic and foreign researchers.

Shao Yuanyan et al. used p-toluenesulfonic acid as a catalyst and selected a stainless steel θ environmental packed tower as the reaction device. The results showed that the optimal yield of methyl ethyl ketone could reach 78.9%. (Shao Yuanyan, Fang Yunjin, et al. Research on the preparation of methyl ethyl ketone by liquid phase dehydration of 2,3-butanediol, Chemistry World, 2013, 54(4): 227-230.) This method has the advantages of high catalyst activity and low energy consumption, but In the preparation process, the selection of sulfuric acid as a catalyst will not only easily cause corrosion to the equipment, but also require an excess of strong alkali to post-process the product after the reaction, which is likely to cause three wastes, which does not conform to the concept of environmentally friendly green chemistry. Huang He et al. (patent CN101293817A, 2008) used ZSM-5 and NaY molecular sieve catalyst to catalyze the dehydration of 2,3-butanediol to produce methyl ethyl ketone, and reacted in a fixed bed with N ₂ as a protective gas. The results showed that 2,3- The conversion rate of butanediol can reach 90.5~100%, and the selectivity of methyl ethyl ketone can reach 83.7~91.3%. However, the raw material concentration is low (30-200 g/L), and a large amount of aqueous solution that does not participate in the reaction needs to be heated to 200-300 °C during the reaction process, resulting in more energy consumption.

SUMMARY OF THE INVENTION

In order to solve the above problems, the purpose of the present invention is to propose a preparation method of a catalyst for producing methyl ethyl ketone by efficient dehydration of 2,3-butanediol.

In order to achieve the above object, the present invention adopts the following technical solutions: a preparation method of a catalyst for dehydration of 2,3-butanediol to prepare methyl ethyl ketone, comprising the following steps:

In step (1), the activated carbon is immersed in an equal amount of barium phosphate hydrochloric acid solution for 2-12 h at room temperature;

In step (2), the activated carbon impregnated in step (1) is dried at 100-150 °C for 2-12 h;

In step (3), the dried activated carbon is calcined for 2-6 h under the protection of N ₂ inert gas to obtain a Ba ₃ (PO ₄ ) ₂ /activated carbon (AC) catalyst.

In step (1) of the present invention, the mass ratio of the load, that is, the barium phosphate to the activated carbon, is 2 to 10%, preferably 8%. According to the maximum water absorption rate of the activated carbon, the activated carbon is immersed in an equal amount of barium phosphate hydrochloric acid solution at room temperature. Immersion for 12 h.

In step (2) of the present invention, the drying temperature is 120° C., and the drying time is 12 h.

In step (3) of the present invention, the flow rate of N ₂ is 10-40 ml/min, and the calcination is performed for 4 h.

The invention also provides the application of the Ba ₃ (PO ₄ ) ₂ /AC catalyst in the reaction of 2,3-butanediol dehydration to methyl ethyl ketone. The reaction process is as follows: continuous reaction is carried out in a fixed-bed reactor, the catalyst is placed in the middle of the quartz tube, the two ends are filled with inert ceramic rings, placed in a tubular heating electric furnace, firstly activated by _N2 protective gas, and then in N2 ₂ The catalytic dehydration reaction of 2,3-butanediol was carried out under a protective gas atmosphere.

Preferably, the activation temperature is 250-350 °C, the flow rate of the N ₂ protective gas is 10-30 ml/min, and the activation treatment time is 1-4 h.

Preferably, the catalytic dehydration reaction temperature is 220-340 °C, the flow rate of the N ₂ protective gas is 10-30 ml/min, and the reaction time is 8-20 h.

Preferably, the mass space velocity of the 2,3-butanediol reaction solution is 0.25-2.5 h ^-1 .

Compared with the prior art, the beneficial effects of the present invention are as follows:

1) The present invention uses 2,3-butanediol as a raw material to prepare methyl ethyl ketone, which avoids the dependence of domestic and foreign methyl ethyl ketone production industries on petroleum non-renewable energy.

2) The catalyst preparation process of the present invention is simple and the preparation cost is low. It does not corrode equipment, is environmentally friendly, and conforms to the concept of green chemistry.

3) The catalyst of the present invention can have good activity and stability in the reaction of 2,3-butanediol catalyzed dehydration to produce methyl ethyl ketone, and the catalyst has high recyclability and utilization rate, and is suitable for industrial application.

4) Compared with the traditional n-butene two-step method, the present invention not only has a simple process, but also can effectively avoid the introduction and generation of toxic and harmful substances, has high operability, and is conducive to realizing industrial production.

Detailed ways

In order to illustrate the present invention more clearly, the present invention will be further described below with reference to the preferred embodiments.

When the catalyst Ba ₃ (PO ₄ ) ₂ /AC of the present invention is used in the catalytic dehydration reaction of 2,3-butanediol, it can achieve excellent catalytic reaction performance, including high catalytic reaction activity and high selection of methyl ethyl ketone sex, etc. Those skilled in the art should understand that the content specifically described below is illustrative rather than restrictive, and should not limit the protection scope of the present invention.

Example

Example 1

(1) According to the maximum water absorption rate of activated carbon, its maximum water absorption rate is 2 in this embodiment, take 100g activated carbon, and according to the load of 8wt%, take 8g barium phosphate, 192g hydrochloric acid solution (1M), and make it into 200g Barium phosphate hydrochloric acid solution, the activated carbon was immersed in the barium phosphate hydrochloric acid solution in equal amount, and immersed at room temperature for 12 h;

(2) Dry the activated carbon impregnated in (1) at 120 °C for 12 h;

(3) The dried activated carbon of (2) was calcined at 450 ℃ for 4 h under the protection of N ₂ inert gas to obtain 8 wt % Ba ₃ (PO ₄ ) ₂ /AC catalyst; the catalyst number was BaP-C-1.

Example 2

Change the load of step (1) in Example 1 to 2%, and other steps are the same as Example 1. The catalyst number is BaP-C-2.

Example 3

Change the load of step (1) in Example 1 to 4%, and other steps are the same as Example 1. The catalyst number is BaP-C-3.

Example 4

Change the load of step (1) in Example 1 to 6%, and other steps are the same as Example 1. The catalyst number is BaP-C-4.

Example 5

Change the load of step (1) in Example 1 to 10%, and other steps are the same as Example 1. The catalyst number is BaP-C-4.

Example 6

The calcination temperature of the catalyst in step (3) of Example 1 was changed, and the catalyst was calcined at 350 °C for 4 h. The loading and other steps were the same as those in Example 1. The catalyst number is BaP-C-6.

Example 7

The calcination temperature of the catalyst in step (3) of Example 1 was changed, and the catalyst was calcined at 400 °C for 4 hours. The loading amount and other steps were the same as those in Example 1. The catalyst number is BaP-C-7.

Example 8

The calcination temperature of the catalyst in step (3) of Example 1 was changed, and the catalyst was calcined at 500 °C for 4 h. The loading amount and other steps were the same as those in Example 1. The catalyst number is BaP-C-8.

Example 9

The calcination temperature of the catalyst in step (3) of Example 1 was changed, and the catalyst was calcined at 550 °C for 4 hours. The loading and other steps were the same as those in Example 1. The catalyst number is BaP-C-9.

Application example

Application example 1

The self-made catalyst BaP-C-1 was used for the gas-phase catalytic dehydration of 2,3-butanediol to produce methyl ethyl ketone. The reaction was carried out in a fixed bed reactor, and 20 g of the catalyst BaP-C-1 was activated at 350 °C for 1 h. During the period, N ₂ protective gas was passed and the flow rate was controlled to 20ml/min, then the temperature of the reactor was lowered to 220 °C, the mass space velocity of the 2,3-butanediol reaction solution was controlled at 0.75 h ^-1 , and the flow rate of N ₂ protective gas during the reaction was controlled at 0.75 h -1 . 20 ml/min. The reaction was terminated after 10 h, and the product was analyzed by gas chromatography.

Application example 2-9

The self-made catalysts Ba-P-2 to Ba-P-9 were used for the gas-phase catalytic dehydration of 2,3-butanediol to produce methyl ethyl ketone, and the operation steps were the same as those of Application Example 1. The dehydration efficiency and selectivity of the catalysts are shown in Table 1.

Comparative example

Comparative Example 1

Step (1) of Example 1 was changed, and the carrier activated carbon was not loaded, and other steps were the same as those of Example 1.

The above catalyst was used for the reaction of 2,3-butanediol gas-phase catalytic dehydration to produce methyl ethyl ketone, and a fixed bed reactor was used to evaluate its activity. The operation steps were the same as those of Application Example 1. The results are shown in Table 2.

Comparative Example 2

Change the reaction temperature conditions in Application Example 1, the reaction temperature of 240° C., the loading amount and the calcination temperature and other conditions and other steps are the same as Application Example 1.

Comparative Example 3

Change the reaction temperature conditions in Application Example 1, the reaction temperature of 260° C., the loading amount and the calcination temperature and other conditions and other steps are the same as Application Example 1.

Comparative Example 4

Change the reaction temperature conditions in Application Example 1, the reaction temperature of 280° C., the loading and the calcination temperature, and other steps are the same as Application Example 1.

Comparative Example 5

Change the reaction temperature conditions in Application Example 1, the reaction temperature of 300° C., the loading and the calcination temperature and other conditions and other steps are the same as Application Example 1.

Comparative Example 6

Change the reaction temperature conditions in Application Example 1, the reaction temperature of 320° C., the loading and the calcination temperature and other conditions and other steps are the same as Application Example 1.

Comparative Example 7

The mass space velocity of the 2,3-butanediol reaction solution in Application Example 1 was changed, the mass space velocity of the 2,3-butanediol reaction solution was controlled at 0.25 h ^-1 , and the conditions such as the loading amount and calcination temperature were the same as those in other steps. example 1.

Comparative Example 8

The mass space velocity of the 2,3-butanediol reaction solution in Application Example 1 was changed, the mass space velocity of the 2,3-butanediol reaction solution was controlled at 0.5h ^-1 , and the conditions such as the load and calcination temperature were the same as those in other steps. example 1.

Comparative Example 9

The mass space velocity of the 2,3-butanediol reaction solution in Application Example 1 was changed, the mass space velocity of the 2,3-butanediol reaction solution was controlled at 1.0h ^-1 , and the conditions such as the load and calcination temperature were the same as those in other steps. example 1.

Comparative Example 10

The mass space velocity of the 2,3-butanediol reaction solution in Application Example 1 was changed, the mass space velocity of the 2,3-butanediol reaction solution was controlled at 1.25 h ^-1 , and the conditions such as the loading amount and calcination temperature were the same as those in other steps. example 1.

The above reaction products were analyzed by gas chromatography, and the results are shown in Table 2.

Table 1 Conversion of 2,3-butanediol and selectivity of methyl ethyl ketone with different catalysts

Table 2 The conversion of 2,3-butanediol and the selectivity of methyl ethyl ketone under different reaction conditions of the comparative example

The present invention uses alkaline earth metal salts as active components for the first time, which is different from the previous Lewis acid catalysts. And the raw material is taken from the by-product 2,3-butanediol of 1,3-propanediol produced by glycerol fermentation in industry, which can effectively develop its downstream products, solve the problem of surplus 2,3-butanediol in industry, and the methyl ethyl ketone has a high yield. Market requirements are wide, which can drive certain economic benefits.

Claims (10)

1. Ba₃（PO₄）₂A preparation method of an AC catalyst, which is used for preparing methyl ethyl ketone by dehydrating 2, 3-butanediol, is characterized by comprising the following steps:

step (1), dipping activated carbon in barium phosphate hydrochloric acid solution for 2-12 h at room temperature;

drying the activated carbon impregnated in the step (1) at 100-150 ℃ for 2-12 h;

step (3), adding the dried active carbon into N₂Roasting for 2-6 h under the protection of inert gas to obtain Ba₃（PO₄）₂an/AC catalyst.

2. The method according to claim 1, wherein in the step (1), the mass ratio of the barium phosphate to the activated carbon is 2 to 10%, preferably 8%.

3. The method of claim 1, wherein the activated carbon is equally immersed in the barium phosphate hydrochloric acid solution at room temperature for 12 hours according to the maximum water absorption of the activated carbon.

4. The method according to claim 1, wherein in the step (2), the drying temperature is 120 ℃ and the drying time is 12 hours.

5. The method of claim 1, wherein in step (3), N is₂The flow rate of (2) is 10-40 ml/min, and roasting is carried out for 4 hours.

6. A catalyst prepared by the process of any one of claims 1 to 5.

7. Use of a catalyst prepared according to any one of claims 1 to 5 in the production of methyl ethyl ketone by dehydration of 2, 3-butanediol.

8. The use according to claim 7, wherein the reaction is carried out by: placing the catalyst in the middle of a quartz tube, filling the two ends with inert ceramic rings, placing in a tubular heating electric furnace, introducing N₂After activation with protective gas, then in N₂And carrying out catalytic dehydration reaction on the 2, 3-butanediol in the protective gas atmosphere.

9. The use according to claim 8, wherein the activation temperature is 250 to 350 ℃ and N₂The flow rate of the protective gas is 10-30 ml/min, and the activation treatment time is 1-4 h.

10. The use according to claim 8, wherein the catalytic dehydration reaction temperature is 220 to 340 ℃, N₂The flow rate of the protective gas is 10-30 ml/min, and the reaction time is 8-20 h; the mass space velocity of the 2, 3-butanediol reaction liquid is 0.25-2.5 h^-1。