CN1485311A

CN1485311A - Process for preparing butyl butyrate

Info

Publication number: CN1485311A
Application number: CNA021307792A
Authority: CN
Inventors: 王海京; 高国强
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2002-09-28
Filing date: 2002-09-28
Publication date: 2004-03-31
Anticipated expiration: 2022-09-28
Also published as: CN1191227C

Abstract

A process of preparing butyl butyrate comprises: gasifying butanol in the case of hydrogen, at the temperature of 200degree C-300 degree C and the pressure of 0.01-1Mpa, passing a reactor, contacting with a catalyst, the formula thereof is CuaZnCrbMcOx wherein a=0.1-10, b=0.1-10, c=0.1-5, M selecting from elements of IVB Group in the Periodic Table, X is the number of oxygen atom satisfying chemical valence of other elements, then separating and collecting butyl butyrate. The process is simple, no waste acids and no wastewater produce which wouldn't pollute environment.

Description

Preparation method of butyl butyrate

Technical Field

The invention relates to a preparation method of butyl butyrate

Background

Butyl butyrate is a fine chemical product, can be used for organic synthesis, and can also be used as a solvent and a perfume. Butyl butyrate is used as a solvent to be applied to nitrocellulose, shellac, coumarone resin and coating. The spice is mainly used for mixing essences of apples, pineapples and the like.

The main method for industrially synthesizing butyl butyrate is to synthesize n-butyric acid and n-butanol in H₂SO₄And (3) esterification under catalysis.

The raw material n-butyric acid is subjected to oxidation synthesis by n-butyraldehyde or n-butanol, so the process route has high cost, in addition, the catalyst sulfuric acid seriously corrodes the device, and a large amount of useless wastewater and waste H are generated by esterification₂SO₄It also causes serious pollution to the environment.

In recent years, foreign countries have begun to synthesize the corresponding 2n esters from alcohols with a carbon number n, such as Elliott D J, pennella, J Catal, 1989; 119: 359, it points out that under the condition of 285 deg.C, 65atm and nitrogen as carrier gas, the conversion rate is 51%, the selectivity is 56% and the by-product of hydrogen is produced.

Compared with the esterification process using sulfuric acid as a catalyst, the process has great progress, but the catalyst activity and selectivity are lower, the reaction needs to be carried out under 65atm, and the conditions are harsh. If the reaction pressure is to be reduced, the catalyst activity and selectivity are lower.

Disclosure of Invention

The object of the present invention is to overcome the above-mentioned drawbacks and to provide a process for the direct preparation of butyl butyrate from butanol, which leads to a higher conversion of butanol and selectivity of butyl butyrate at lower pressures.

The method provided by the invention comprises the following steps: gasifying butanol in the presence of hydrogen, passing the gasified butanol through a reactor at the temperature of 200-300 ℃ and the pressure of 0.01-1MPa, and reacting the gasified butanol with a catalyst expressed as Cu_aZnCr_bM_cO_xContacting the catalyst, separating and collecting butyl butyrate. Wherein a is 0.1 to 10, preferably 0.2 to 8, more preferably 0.5 to 7; b is 0.1 to 10, preferably 0.2 to 8.5, more preferably 0.4 to 7; c is 0.1 to 5, preferably 0.2 to 4, more preferably 0.3 to 3; m is an element selected from group IVB, preferably Ti and Zr, and X is the number of oxygen atoms required to satisfy the valence requirements of the other elements.

In particular, the invention provides a methodThe method comprises the following steps: mixing hydrogen and butanol according to the molar ratio of 0.1-20: 1 to form a gas-liquid mixture, continuously introducing the gas-liquid mixture into a gasifier for gasification, and introducing the gas-liquid mixture into a fixed bed reactor filled with a catalyst for reaction at the temperature of 200-350 ℃, the pressure of 0.01-1MPa and the volume Liquid Hourly Space Velocity (LHSV) of butanol of 0.7-4 hours^-1The reaction is carried out under the condition, and the target product butyl butyrate is separated from the effluent after the reaction through condensation.

The gasification of the butanol in the above process may be carried out in any manner disclosed in the prior art, most commonly by gasifying the butanol in a hot hydrogen-containing gas stream and contacting the compound with a catalyst.

The reaction for directly preparing butyl butyrate from butanol is a gas-solid phase reaction, and the fact that the raw material is in a gas phase is very important, so that the reaction temperature must be higher than the dew points of reactants and products. The conversion increases with increasing temperature, since the reaction proceeds kinetically in favor of an increasing temperature. However, when the temperature is too high, the selectivity of butyraldehyde and butyric acid is obviously increased, and the selectivity of butyl butyrate is reduced, so that the temperature is preferably kept between 200 ℃ and 350 ℃, and more preferably between 250 ℃ and 300 ℃.

The butyl butyrate reaction network comprises a plurality of equilibrium reactions, pressure change tends to influence the equilibrium of each step, the retention time of materials in a catalyst bed layer is increased along with the increase of pressure and the same airspeed, the reaction is more complete, the reaction of reducing the molecular number is favorably carried out towards the completion direction, but the reaction of increasing the molecular number is unfavorable, the reaction pressure is reduced, and the functions are opposite. The pressure chosen in the present invention is from 0.01 to 1MPa, preferably from 0.1 to 0.8 MPa.

The hydrogen-alcohol ratio determines the retention time and partial pressure of the raw material in the reactor, the molar ratio of the hydrogen and the alcohol is too low, so that the retention time of the material in the reactor is too long, side reactions are increased, the impurity content is increased, the heat transfer rate and the mass transfer rate can be improved by increasing the hydrogen-alcohol ratio, but the energy consumption of the device is increased and the operation cost is obviously increased because the hydrogen-alcohol ratio is too large, and the hydrogen-alcohol ratio selected in the invention is 0.1-20: 1, preferably 0.2-10, more preferably 0.5-3: 1.

The method adopts butanol Liquid Hourly Space Velocity (LHSV)0.7-4 hours^-1Preferably 0.9 to 2 hours^-1. If the liquid hourly space velocity is increased further, the reaction temperature will have to be increased to ensure a higher conversion, but the selectivity to butyl butyrate will be reduced.

The catalyst can be prepared by the following method: dissolving soluble salt of required metal, preferably nitrate in decationized water, stirring at room temperature, precipitating with alkali, preferably ammonia water to pH 4-9, aging for 1-4 hr, filtering, washing with water, collecting precipitate, drying at 100-250 deg.C for 4-20 hr, and calcining at 400-600 deg.C for 2-24 hr.

The catalyst used in the invention needs to be pre-reduced before use, the reducing agent can adopt reducing gas such as hydrogen or carbon monoxide, the reduction reaction is carried out at the temperature of 300 ℃ of 250-0.1-6 MPa, and the flow rate of the reducing gas is 50-500 ml/min relative to each ml of the catalyst.

The method is suitable for preparing the C2-C12 ester by taking C1-C6 alcohol as a raw material.

Compared with the traditional esterification process, the method adopts butanol to synthesize the butyl butyrate in one step, greatly simplifies the process flow, has no waste acid, waste water discharge and no pollution to the environment, does not need anticorrosive materials for devices, can greatly reduce the equipment investment, and can produce hydrogen as a byproduct. Compared with the existing Cu-Zn-Al catalyst, the reaction pressure is greatly reduced, the reaction conversion rate and the selectivity of a target product are obviously improved, the conversion rate of thebutanol is 62 mol% and the selectivity of the butyl butyrate can reach 80 mol% under the conditions of 255-265 ℃ and 0.4 MPa.

Detailed Description

The invention is further illustrated below by way of examples, without being limited thereto.

Example 1

Preparation example of catalyst:

261 g of copper nitrate (chemical purity, Beijing chemical plant), 298 g of zinc nitrate (chemical purity, Beijing chemical plant), 116 g of chromic anhydride (chemical purity, Beijing chemical plant), 134 g of zirconium nitrate (chemical purity, Beijing chemical plant) were dissolved in 1000 ml of deionized water, and then, in the deionized waterMixing with ammonia water under stirring to generate precipitate, controlling pH to 7 + -1, filtering the precipitate, washing, drying at 110 + -10 deg.C for 12 hr, and calcining at 400 + -60 deg.C for 24 hr to obtain catalyst precursor A: cu_1.07ZnCr_1.16Zr_0.49O_4.79

Example 2

Preparation example of catalyst:

dissolving 96.6 g of copper nitrate (chemical purity, beijing chemical plant), 300 g of zinc nitrate (chemical purity, beijing chemical plant), 29.7 g of chromic anhydride (chemical purity, beijing chemical plant), 520.9 g of zirconium nitrate (chemical purity, beijing chemical plant) in 760 ml of deionized water, mixing with ammonia water under stirring to generate a precipitate, controlling the PH6 ± 1, filtering and washing the generated precipitate at 200 ± 10 ℃ for drying for 4 hours, and calcining at 500 ± 60 ℃ for 10 hours to prepare a catalyst precursor B: cu_0.4ZnCr_0.3Zr_1.95O_5.8。

Example 3

Preparation example of catalyst:

52.2 g of copper nitrate (chemical purity, Beijing chemical plant), 13 g of zinc nitrate (chemical purity, Beijing chemical plant), 28.9 g of chromic anhydride (chemical purity, Beijing chemical plant), 6.9 g of titanium dioxide (chemical purity, Beijing chemical plant) were dispersed in 280 ml of deionized water, and then mixed with 23 to 25% by weight of aqueous ammonia under stirring to form a precipitate,controlling the pH value of 7 +/-1, filtering and washing the generated precipitate, drying the precipitate at 120 ℃ for 6 hours, and roasting the precipitate at 500 +/-60 ℃ for 4 hours to prepare a catalyst precursor C: cu₅ZnCr_6.7Ti₂O_20.1。

Example 4

Preparation example of catalyst:

52.2 g of copper nitrate (chemical purity, Beijing chemical plant), 20.3 g of zinc nitrate (chemical purity, Beijing chemical plant), 19.6 g of chromic anhydride (chemical purity, Beijing chemical plant) and 4.3 g of titanium dioxide (chemical purity, Beijing chemical plant) were dispersed in 300 ml of deionized water, and then mixed with 23 to 25 wt% ammonia water under stirring to form a precipitate, and the pH was controlled to 5 + -1, and the precipitate was filtered and washed at 120 deg.CDrying for 6 hours, and roasting for 4 hours at 500 +/-60 ℃ to prepare a catalyst precursor D: cu_3.3ZnCr₃Ti_0.83O_10.5。

Example 5

Pretreatment of a catalyst:

after the catalyst A was shaped, particles of 26 to 40 mesh were produced, 5 ml of the particles were charged into a stainless steel tubular reactor having an inner diameter of 8 mm and a length of 400 mm, pure hydrogen was introduced at a flow rate of 500 ml/min under a pressure of 2.0MPa, and the catalyst was reduced at 300 ℃ for 4 hours, in the following examples the catalyst pre-reduction was carried out in accordance with this method.

Example of catalytic reaction:

after the catalyst reduction is finished, adjusting the temperature of the system to be 255 ℃, the pressure to be 0.4MPa and the molar ratio of the hydrogen to the alcohol to be 2: 1, taking butanol as the raw material and the liquid hourly space velocity to be 0.9hr^-1The reaction was carried out, and the reaction product was measured by FID using a gas chromatograph equipped with a column packed with PEG20000, and the results are shown in Table 1.

Example 6

Example of catalytic reaction:

catalyst B was prepared and the procedure in example 5 was repeated, except that the reaction pressure was 0.1MPa and the results are shown in Table 1

Example 7

Example of catalytic reaction:

taking catalyst C, operating according to the method of example 5, adjusting the system temperature to 265 deg.C, the pressure to 0.1MPa, the hydrogen-alcohol molar ratio to 1: 1, using butanol as raw material, the liquid hourly space velocity to 1.5hr^-1The reaction was carried out, and the reaction product was measured by FID using a gas chromatograph equipped with a column packed with PEG20000, and the results are shown in Table 1.

Example 8

Example of catalytic reaction:

taking catalyst D, operating according to the method of example 5, adjusting the system temperature to 280 ℃, the pressure to 0.8MPa, the hydrogen-alcohol molar ratio to 0.5: 1, using butanol as raw material, the liquid hourly space velocity to 1.5hr^-1Thereaction was carried out, and the reaction product was measured by FID using a gas chromatograph equipped with a column packed with PEG20000, and the results are shown in Table 1.

TABLE 1

	Example 5	Example 6	Example 7	Example 8
	Example 5	Example 6	Example 7	Example 8	Catalyst numbering	A	B	C	D
Reaction temperature of	255	255	265	280	Catalyst numbering	A	B	C	D
Reaction temperature of	255	255	265	280	Reaction pressure, MPa	0.4	0.1	0.1	0.8
Molar ratio of hydrogen to alcohol	2∶1	2∶1	1∶1	0.5	Reaction pressure, MPa	0.4	0.1	0.1	0.8
Molar ratio of hydrogen to alcohol	2∶1	2∶1	1∶1	0.5	Butanol liquid hourly space velocity LHSV, hr^-1	0.9	0.9	1.5	1.5
Conversion of butanol, mol%	62	60	64	60	Butanol liquid hourly space velocity LHSV, hr^-1	0.9	0.9	1.5	1.5
Conversion of butanol, mol%	62	60	64	60	Butyl butyrate selectivity, mol%	80	74	76	86

Claims

1. A preparation method of butyl butyrate comprises the following steps: gasifying butanol in the presence of hydrogen, passing the gasified butanol through a reactor at the temperature of 200-350 ℃ and the pressure of 0.01-1MPa, and reacting the gasified butanol with a catalyst expressed as Cu_aZnCr_bM_cO_xContacting the catalyst, separating and collecting butyl butyrate, wherein a is 0.1-10, b is 0.1-10, c is 0.1-5, M is one element selected from IVB group, and X is oxygen atom number required for meeting the valence requirement of other elements.

2. The process according to claim 1, wherein a is 0.2 to 8, b is 0.2 to 8.5, c is 0.2 to 4, and M is selected from Ti and Zr.

3. The process according to claim 1 or 2, wherein a is 0.5 to 7, b is 0.4 to 7, and c is 0.3 to 3.

4. The process according to claim 1, wherein the reaction temperature is 250-300 ℃.

5. The process according to claim 1, wherein the reaction pressure is from 0.1 to 0.8 MPa.

6. The process according to claim 1, wherein the ratio of the hydrogen to the alcohol is 0.1 to 20: 1.

7. The production process according to claim 1 or 6, wherein the ratio of hydrogen to alcohol is 0.2 to 10.

8. The process of claim 1, wherein the liquid butanol hourly space velocity is from 0.7 to 4 hours^-1。

9. The process of claim 8, wherein the liquid butanol hourly space velocity is from 0.9 to 2 hours^-1。

10. The process according to claim 1, wherein the catalyst is prepared by the following method: dissolving soluble salt of required metal in de-cationic water, stirring, precipitating with alkali until pH is 4-9, aging for 1-4 hr, filtering, washing with water, collecting precipitate, drying at 250 deg.C for 4-20 hr and calcining at 600 deg.C for 2-24 hr.