Preparation method of p-phenylether

Abstract

The invention discloses a preparation method of p-phenylethylether, p-phenylethylether is prepared from hydroquinone and diethyl carbonate in a high-selectivity manner under the catalysis of a catalyst, and the catalyst is a Zr / Ho-loaded SAPO molecular sieve catalyst. The process is green and environment-friendly, few in three wastes, high in catalyst reaction activity, good in stability, simple to separate and high in product yield, and has a good industrial application prospect.

Description

Technical Field

[0001] The invention belongs to the field of chemical synthesis, and particularly relates to a method for preparing phenylene diethyl ether. Background Art

[0002] P-phenylenediethyl ether, also known as 1,4-diethoxybenzene, p-diethoxybenzene, hydroquinone diethyl ether, hydroquinone diethyl ether, melting point 69-72℃, boiling point 246℃. P-phenylenediethyl ether is a white crystal with a strong anise flavor, which can be used to prepare spices or as a flavor enhancer. It is also an important organic synthesis intermediate, used in the synthesis of pesticides, medicines, fuels, reagents, etc.

[0003] At present, the synthesis methods of p-phenylenediethyl ether include ethyl bromide method and diethyl sulfate method. The ethyl bromide method is to use hydroquinone and ethyl bromide to undergo substitution reaction under alkaline conditions to remove two molecules of hydrogen bromide to obtain p-phenylenediethyl ether. This method has low yield, and halogens corrode the equipment severely, requiring large equipment investment and making industrial production difficult. The diethyl sulfate method is to use hydroquinone and diethyl sulfate to directly react to obtain p-phenylenediethyl ether. However, the raw material diethyl sulfate is a highly toxic chemical, which is highly dangerous to transport and store, and has the disadvantages of low product purity and difficulty in handling the three wastes.

[0004] Therefore, it is of great significance to develop a new process for the preparation of p-phenylenediethyl ether which is green and environmentally friendly, has high product selectivity and good catalyst stability. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for preparing phenylene diethyl ether, which uses hydroquinone and diethyl carbonate to generate phenylene diethyl ether under the catalytic action of a catalyst. In the preparation method of the present invention, the raw material diethyl carbonate has low toxicity, and its transportation and storage safety is much higher than that of ethyl bromide and diethyl sulfate, and the product selectivity is high, and only CO2 and ethanol are produced as byproducts, which is green and environmentally friendly; and the catalyst has strong reaction activity, good stability, and simple separation, and has good prospects for industrial application.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing phenylene diethyl ether, wherein in the presence of a catalyst, hydroquinone and diethyl carbonate are catalyzed to generate phenylene diethyl ether; wherein the catalyst is a Zr / Ho-loaded SAPO molecular sieve catalyst.

[0008] The SAPO molecular sieve catalyst of the present invention uses Zr / Ho elements to reasonably modify the acid and basic sites on the SAPO molecular sieve to obtain a supported catalyst, which can improve the selectivity of the product to phenylene diethyl ether. Secondly, the Zr / Ho elements are supported in the unique pore structure of the molecular sieve, which optimizes the distribution of the acid and basic sites on the molecular sieve, so that the supported molecular sieve catalyst has a more significant enhancement effect on the catalytic activity.

[0009] In one embodiment of the present invention, the molar ratio of hydroquinone to diethyl carbonate is 1:(2-2.2).

[0010] In one embodiment of the present invention, the mass ratio of hydroquinone to the solvent is 1:(1-3).

[0011] In one embodiment of the present invention, the mass of the catalyst is 5-20% of the mass of hydroquinone.

[0012] In one embodiment of the present invention, the reaction pressure is 0.2-1 MPaG, the temperature is 70-150° C., and the reaction time is 4-10 h.

[0013] In one embodiment of the present invention, in the Zr / Ho-loaded SAPO molecular sieve catalyst, the total mass of the zirconium source and the holmium source is 0.1-0.3 times the mass of the SAPO molecular sieve; preferably, the molar ratio of Zr and Ho elements is Zr:Ho=1:(0.2-1).

[0014] In one embodiment of the present invention, the SAPO molecules are selected from one or more of SAPO-5, SAPO-11, SAPO-18, SAPO-34, and SAPO-44.

[0015] In one embodiment of the present invention, the Zr / Ho supported SAPO molecular sieve catalyst is prepared by the following steps:

[0016] S1: The zirconium source and the holmium source are dissolved in water to obtain an aqueous solution;

[0017] S2: immersing the SAPO molecular sieve in an aqueous solution;

[0018] S3: calcining the dried molecular sieve to obtain a Zr / Ho-loaded SAPO molecular sieve catalyst.

[0019] In one embodiment of the present invention, the zirconium source in S1 is an organic salt and / or an inorganic salt containing zirconium element, preferably one or more of zirconium nitrate, zirconium sulfate, zirconium chloride and zirconium acetate.

[0020] In one embodiment of the present invention, the holmium source in S1 is an organic salt and / or inorganic salt containing the holmium element, preferably one or more of holmium nitrate pentahydrate, holmium sulfate hydrate, holmium chloride, holmium bromide, holmium iodide, holmium acetate, holmium nitrate and holmium sulfate octahydrate.

[0021] In one embodiment of the present invention, the drying method in S3 is preferably freeze drying.

[0022] In one embodiment of the present invention, the calcination temperature in S3 is 400-600° C. and the calcination time is 12-24 h.

[0023] Another object of the present invention is to provide a Zr / Ho-supported SAPO molecular sieve catalyst.

[0024] A Zr / Ho loaded SAPO molecular sieve catalyst is prepared by the above method, wherein the total mass of the zirconium source and the holmium source in the catalyst is 0.1-0.3 times the mass of the SAPO molecular sieve; preferably, the molar ratio of Zr to Ho is Zr:Ho=1:(0.2-1).

[0025] In one embodiment of the present invention, the SAPO molecules in the catalyst are selected from one or more of SAPO-5, SAPO-11, SAPO-18, SAPO-34, and SAPO-44.

[0026] Another object of the present invention is to provide phenylene diethyl ether, which is prepared by the above method.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) By using the Zr / Ho-loaded SAPO molecular sieve catalyst, the conversion rate of hydroquinone can reach up to 90%, and the selectivity of p-phenylene diethyl ether can reach up to about 94%.

[0029] (2) The Zr / Ho-loaded SAPO molecular sieve catalyst is easy to separate and has strong catalyst activity, good stability, and can be applied many times. The conversion rate of hydroquinone obtained by using the catalyst for 15 times is still above 80%, and the catalyst can be calcined and regenerated, which has prospects for industrial application. DETAILED DESCRIPTION

[0030] In order to better understand the present invention, the content of the present invention is further described below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0031] In the following examples, the conversion rate of hydroquinone and the selectivity of p-phenylenediethyl ether can be calculated according to the composition of the reaction solution. The analysis method adopts gas chromatography, and the instrument is Shimadzu GC-2030 gas chromatograph.

[0032] Sources of some raw materials used:

[0033] Hydroquinone, diethyl carbonate, zirconium nitrate, zirconium sulfate, zirconium chloride, holmium nitrate pentahydrate, holmium sulfate hydrate, holmium chloride: Aladdin Technology Co., Ltd.

[0034] SAPO-5, SAPO-11, SAPO-34 molecular sieves: Tianjin Nanhua Catalyst Co., Ltd.

[0035] Ethanol, acetonitrile: Beijing Inokai Technology Co., Ltd.

[0036] Example 1

[0037] Preparation of catalyst:

[0038] (1) Dissolve 3.39 g of zirconium nitrate and 2.21 g of holmium nitrate pentahydrate in 500 g of pure water, and stir to dissolve and mix evenly; ensure that the molar ratio of Zr to Ho is Zr:Ho=1:0.5.

[0039] (2) 37.33 g of SAPO-5 molecular sieve was immersed in the aqueous solution of step (1) and stirred at room temperature for 5 h; the total mass of the zirconium source and the holmium source was ensured to be 0.15 times the mass of the SAPO-5 molecular sieve.

[0040] (3) freeze-drying the above solution at a pressure of 50 PaA and a temperature of -25°C for 12 h;

[0041] (4) The dried molecular sieve was calcined in an air atmosphere to obtain a Zr / Ho-loaded SAPO-5 molecular sieve catalyst at a calcination temperature of 400° C. for 12 h.

[0042] Batch operation conditions of hydroquinone and diethyl carbonate reactor:

[0043] First, add 110g of hydroquinone, 165g of ethanol and 5.5g of Zr / Ho-loaded SAPO-5 molecular sieve catalyst into the reactor, stir and dissolve at 50°C for half an hour, and then add 236g of diethyl carbonate; the system is pressurized to 0.4MPaG, heated to 80°C, stirred at 400r / min, and kept stirring for 6h.

[0044] After the reaction was completed under the above conditions, sampling was performed for analysis. The sample was diluted 10 times with acetonitrile and then the composition of the reaction liquid was analyzed by gas chromatography. The conversion rate of hydroquinone was calculated to be 85%, and the selectivity of p-phenylenediethyl ether was 88%.

[0045] Example 2

[0046] Preparation of catalyst:

[0047] (1) Dissolve 2.83 g of zirconium sulfate and 5.09 g of holmium sulfate hydrate in 500 g of pure water, and stir to dissolve and mix evenly; ensure that the molar ratio of Zr and Ho elements is Zr:Ho=1:0.8.

[0048] (2) 39.6 g of SAPO-11 molecular sieve was immersed in the aqueous solution of step (1) and stirred at room temperature for 8 h; the total mass of the zirconium source and the holmium source was ensured to be 0.2 times the mass of the SAPO-11 molecular sieve.

[0049] (3) freeze-drying the above solution at a pressure of 100 PaA and a temperature of -15°C for 18 h;

[0050] (4) The dried molecular sieve was calcined in an air atmosphere to obtain a Zr / Ho-loaded SAPO-11 molecular sieve catalyst at a calcination temperature of 500° C. for 18 h.

[0051] Batch operation conditions of hydroquinone and diethyl carbonate reactor:

[0052] First, add 110g of hydroquinone, 220g of ethanol and 11g of Zr / Ho loaded SAPO-11 molecular sieve catalyst into the reactor, stir and dissolve at 50°C for half an hour, and then add 247.8g of diethyl carbonate; pressurize the system to 0.8MPaG, heat to 120°C, stir at 400r / min, and keep stirring for 8h.

[0053] After the reaction was completed under the above conditions, sampling was performed for analysis. The sample was diluted 10 times with acetonitrile and then the composition of the reaction liquid was analyzed by gas chromatography. The conversion rate of hydroquinone was calculated to be 90%, and the selectivity of p-phenylenediethyl ether was 94%.

[0054] Example 3

[0055] Preparation of catalyst:

[0056] (1) Dissolve 2.33 g zirconium chloride and 2.71 g holmium chloride in 500 g pure water, stir and mix until uniform; ensure that the molar ratio of Zr to Ho is Zr:Ho=1:1.

[0057] (2) Immerse 20.16 g of SAPO-34 molecular sieve in the aqueous solution of step (1) and stir at room temperature for 10 h; ensure that the total mass of the zirconium source and the holmium source is 0.25 times the mass of the SAPO-34 molecular sieve.

[0058] (3) freeze-drying the above solution at a pressure of 200 PaA and a temperature of -10°C for 24 h;

[0059] (4) The dried molecular sieve was calcined in an air atmosphere to obtain a Zr / Ho-loaded SAPO-34 molecular sieve catalyst at a calcination temperature of 600° C. for 24 h.

[0060] Batch operation conditions of hydroquinone and diethyl carbonate reactor:

[0061] First, add 110g of hydroquinone, 330g of ethanol and 16.5g of Zr / Ho-loaded SAPO-34 molecular sieve catalyst into the reactor, stir and dissolve at 50°C for half an hour, and then add 259.6g of diethyl carbonate; the system is pressurized to 1MPaG, heated to 150°C, stirred at 400r / min, and kept stirring for 10h.

[0062] After the reaction was completed under the above conditions, sampling was performed for analysis. The sample was diluted 10 times with acetonitrile and then the composition of the reaction solution was analyzed by gas chromatography. The conversion rate of hydroquinone was calculated to be 88%, and the selectivity of p-phenylenediethyl ether was 90%.

[0063] Example 4

[0064] The catalyst was obtained by applying the conditions of Example 2 15 times. The initial catalyst preparation method, reaction conditions and raw material ratio were the same as those of Example 2. The reaction was carried out under the above conditions. Sampling and analysis showed that the conversion rate of hydroquinone was 80% and the selectivity of p-phenylenediethyl ether was 83.7%.

[0065] Comparative Example 1

[0066] The catalyst was prepared in the same manner as in Example 2, the main difference being that no holmium source was added, and other preparation conditions and reaction conditions were the same as in Example 2. Under the above conditions, sampling and analysis showed that the conversion rate of hydroquinone was 43%, and the selectivity of p-phenylene diethyl ether was 65.3%.

[0067] Comparative Example 2

[0068] The catalyst was prepared in the same manner as in Example 2, the main difference being that no zirconium source was added, and other preparation conditions and reaction conditions were the same as in Example 2. Under the above conditions, sampling and analysis showed that the conversion rate of hydroquinone was 51%, and the selectivity of p-phenylene diethyl ether was 69.7%.

[0069] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Those skilled in the art will appreciate that, under the guidance of this specification, some modifications or adjustments may be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A method for preparing phenylene diethyl ether, characterized in that: In the preparation method, hydroquinone and diethyl carbonate are catalyzed to generate phenylene diethyl ether under the action of a catalyst; Wherein, the catalyst is a Zr / Ho-loaded SAPO molecular sieve catalyst.

2. The preparation method according to claim 1, characterized in that: The molar ratio of hydroquinone to diethyl carbonate is 1:(2-2.2); And / or, the mass of the catalyst is 5-20% of the mass of the hydroquinone.

3. The preparation method according to claim 1 or 2, characterized in that: The reaction pressure is 0.2-1 MPaG, the temperature is 70-150° C., and the reaction time is 4-10 h.

4. The preparation method according to any one of claims 1 to 3, characterized in that In the Zr / Ho-loaded SAPO molecular sieve catalyst, the total mass of the zirconium source and the holmium source is 0.1-0.3 times the mass of the SAPO molecular sieve; Preferably, the molar ratio of Zr to Ho is Zr:Ho=1:(0.2-1); And / or, the SAPO molecules are selected from one or more of SAPO-5, SAPO-11, SAPO-18, SAPO-34, and SAPO-44.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The Zr / Ho-supported SAPO molecular sieve catalyst is prepared by the following steps: S1: The zirconium source and the holmium source are dissolved in water to obtain an aqueous solution; S2: immersing the SAPO molecular sieve in an aqueous solution; S3: calcining the dried molecular sieve to obtain a Zr / Ho-loaded SAPO molecular sieve catalyst.

6. The preparation method according to claim 5, characterized in that: The zirconium source in S1 is an organic salt and / or an inorganic salt containing zirconium element, preferably one or more of zirconium nitrate, zirconium sulfate, zirconium chloride and zirconium acetate; And / or, the holmium source in S1 is an organic salt and / or an inorganic salt containing the holmium element, preferably one or more of holmium nitrate pentahydrate, holmium sulfate hydrate, holmium chloride, holmium bromide, holmium iodide, holmium acetate, holmium nitrate and holmium sulfate octahydrate.

7. The preparation method according to claim 5, characterized in that: The drying method in S3 is preferably freeze drying; And / or, the calcination temperature in S3 is 400-600° C. and the calcination time is 12-24 h.

8. A Zr / Ho-supported SAPO molecular sieve catalyst, the catalyst being prepared by the method according to any one of claims 5 to 7, characterized in that: The total mass of the zirconium source and the holmium source in the catalyst is 0.1-0.3 times the mass of the SAPO molecular sieve; Preferably, the molar ratio of Zr to Ho is Zr:Ho=1:(0.2-1); And / or, the SAPO molecules are selected from one or more of SAPO-5, SAPO-11, SAPO-18, SAPO-34, and SAPO-44.

9. A phenylene diethyl ether, which is prepared by the method described in any one of claims 1 to 7.