Method for preparing alpha, alpha '-dihydroxy-1, 3-diisopropyl benzene

Abstract

The invention discloses a method for preparing alpha, alpha '-dihydroxy-1, 3-diisopropylbenzene, which comprises the following steps: taking 1, 3-diisopropylbenzene and chlorine as raw materials, carrying out substitution reaction under the illumination of an acid-binding agent and ultraviolet rays, and then reacting with sodium hydroxide to obtain the alpha, alpha'-dihydroxy-1, 3-diisopropylbenzene (DC). The method is short in reaction period and high in reaction efficiency, the obtained alpha, alpha '-dihydroxy-1, 3-diisopropyl benzene is stable in quality, the problems of low raw material utilization rate, more side reactions, high production energy consumption, large wastewater amount, poor safety and the like in a traditional process are solved, and a new thought is provided for industrial production of the alpha, alpha'-dihydroxy-1, 3-diisopropyl benzene.

Description

Technical Field

[0001] The present invention relates to a method for preparing α,α'-dihydroxy-1,3-diisopropylbenzene, belonging to the technical field of compound preparation. Background Art

[0002] α,α'-dihydroxy-1,3-diisopropylbenzene (abbreviated as DC), also known as bis-(2-hydroxyisopropyl)benzene, diisopropylbenzene alcohol, etc., is mainly used in the synthesis of cross-linking agents and activators for polyethylene plastics, etc., and is the main raw material for the production of the cross-linking agent bis-(tert-butylperoxyisopropyl)benzene (BIBP). BIBP is an upgraded product of dicumyl peroxide (DCP), commonly known as "odorless DCP". BIBP has no odor during the cross-linking process, has high cross-linking efficiency, less dosage under the same cross-linking effect (its dosage is only 2 / 3 of that of DCP), and the products have good heat resistance, low-temperature flexural properties, and pressure-resistant deformation properties. With the enhancement of people's environmental awareness and the improvement of living quality, the demand for BIBP by users will be increasing.

[0003] In the existing industry, the methods for synthesizing α,α'-dihydroxy-1,3-diisopropylbenzene mainly include:

[0004] Patent document CN103159592A discloses a production method of bis-(2-hydroxyisopropyl)benzene. In this synthesis method, diisopropylbenzene and air are subjected to an oxidation reaction for 10 - 24 hours under the catalytic action of 10 - 20% NaOH at a reaction temperature of 85 - 105°C and a reaction pressure of 0.20 - 0.35 MPa, and then a reduction reaction with the reducing agent Na2S for 5 - 7 hours to obtain bis-(2-hydroxyisopropyl)benzene. This synthesis method has a long reaction period, many by-products, large material consumption, the consumption of 10% - 20% NaOH solution is 8 - 10 times the weight of diisopropylbenzene, and a large amount of wastewater, which is not conducive to green and clean production.

[0005] Patent document CN103396292A discloses a method for industrial production of A,A'-dihydroxy-1,3-diisopropylbenzene. In this synthesis method, diisopropylbenzene, sodium carbonate, water, and the initiator azobisisobutyronitrile are sequentially added to the oxidation tower, the temperature of the oxidation tower is controlled at 80 - 95°C, compressed air is introduced from the bottom for oxidation, and the reaction is carried out under insulation at a pressure of 0.3 - 0.4 MPa for 9 - 11 hours, while maintaining the pH of the reaction solution at 7.5 - 10. Then, it reacts with the reducing agent sodium sulfite at 70 - 90°C for 1 - 2 hours, and the final product A,A'-dihydroxy-1,3-diisopropylbenzene is obtained after liquid separation, crystallization, and drying. This synthesis method has complex operations, a long reaction period, a large amount of wastewater, a large amount of the reducing agent sodium sulfite consumed, about half of that of diisopropylbenzene, large material consumption and energy consumption, and high production costs.

[0006] Patent document CN107652164A discloses a method for producing diisopropylbenzyl alcohol. In this synthesis method, diisopropylbenzene is pumped into an oxidation tower, a liquid alkali solution is added, and after heating, compressed air is introduced. The temperature is maintained at 90 - 100 °C, and the pressure in the oxidation tower is 2.8 - 3.1 kg. The obtained oxidation liquid and the reducing agent sodium sulfite undergo a heterogeneous reduction reaction at 75 - 100 °C to obtain crude diisopropylbenzyl alcohol. The obtained crude diisopropylbenzyl alcohol is stirred and recrystallized with 92 - 98% diisopropylbenzene to obtain refined diisopropylbenzyl alcohol. This synthesis method has complex process, many side reactions, large material consumption and energy consumption, and high production cost. The diisopropylbenzene used for washing contains a large amount of by-products. Recycling and reuse will affect the oxidation process, cause the accumulation of by-products, and deteriorate the product quality. However, in the reduction process, the use of solid sodium sulfite for heterogeneous reduction with the oxidation liquid will result in incomplete reduction reaction, causing deviation in product quality and thus affecting the low product yield.

[0007] In summary, the current production process of α,α'-dihydroxy-1,3-diisopropylbenzene has disadvantages such as long reaction cycle, high reaction pressure, poor safety, many side reactions, large material consumption and energy consumption, and a large amount of production wastewater. Therefore, it is of great significance to develop a new production process that is green, environmentally friendly, safe, efficient, simple and feasible. Summary of the Invention

[0008] In view of the deficiencies of the prior art, the present invention provides a method for preparing α,α'-dihydroxy-1,3-diisopropylbenzene. This method uses 1,3-diisopropylbenzene and chlorine gas as raw materials, and undergoes a substitution reaction under an acid-binding agent and ultraviolet light irradiation, and then reacts with sodium hydroxide to obtain α,α'-dihydroxy-1,3-diisopropylbenzene (DC). The method of the present invention has a short reaction cycle and high reaction efficiency, and the obtained α,α'-dihydroxy-1,3-diisopropylbenzene has stable quality, overcoming the problems of low utilization rate of raw materials, many side reactions, high production energy consumption, large amount of wastewater, and poor safety in the traditional process, providing a new idea for the industrial production of α,α'-dihydroxy-1,3-diisopropylbenzene.

[0009] The specific technical solution of the present invention is as follows:

[0010] A method for preparing α,α'-dihydroxy-1,3-diisopropylbenzene, the method comprising the following steps:

[0011] 1) Performing a substitution reaction on 1,3-diisopropylbenzene and chlorine gas under an acid-binding agent and ultraviolet light irradiation;

[0012] 2) Adding a sodium hydroxide solution to the reaction product of step 1) for reaction;

[0013] 3) Filter the reaction solution obtained in step 2), wash and dry the obtained filter cake to obtain α,α'-dihydroxy-1,3-diisopropylbenzene (DC).

[0014] Furthermore, in step 1), the acid-binding agent is a nitrogen-containing organic base. On the one hand, the organic base acts as a catalyst to activate the tertiary hydrogen on the isopropyl group, promote the departure of hydrogen, and improve the reactivity of the tertiary hydrogen; on the other hand, it can capture the by-product hydrogen chloride and promote the forward reaction. Exemplarily, the organic base can be at least one of triethylamine, pyridine, hexamethylenetetramine, etc.

[0015] Furthermore, in step 1), when the acid-binding agent is triethylamine, the product yield is higher and the operability is stronger.

[0016] Furthermore, in step 1), the molar ratio of 1,3-diisopropylbenzene to nitrogen in the organic base is 1:(2 - 2.2).

[0017] Furthermore, in step 1), the reaction is carried out in a reaction kettle, and chlorine gas is introduced into the reaction kettle in the form of a gas. A tail gas absorption device is provided on the reaction kettle. Preferably, first add 1,3-diisopropylbenzene and the acid-binding agent into the reaction kettle, and then continuously introduce chlorine gas into the mixture of 1,3-diisopropylbenzene and the acid-binding agent. To ensure sufficient contact between chlorine gas and 1,3-diisopropylbenzene and the acid-binding agent, chlorine gas is preferably introduced from the bottom of the reaction kettle. During the whole reaction process, chlorine gas is continuously introduced into the reaction kettle, and the pressure of chlorine gas in the system ≤ 0.1 Mpa.

[0018] Furthermore, in step 1), the wavelength of the ultraviolet light emitted by the ultraviolet lamp is preferably 350 - 365 nm.

[0019] Furthermore, in step 1), the reaction temperature is 0°C - 20°C, such as 0°C, 5°C, 10°C, 15°C, 20°C.

[0020] Furthermore, in step 1), stop introducing chlorine gas when 1,3-diisopropylbenzene is completely converted. In actual production, the content of 1,3-diisopropylbenzene can be detected, and when its content in the system is less than 1%, the reaction is considered complete; it is also possible to detect the weight gain of the system, and when the weight gain of the system is 40% and above of the added mass of 1,3-diisopropylbenzene, the reaction is considered complete. Generally, within this reaction temperature range, the reaction time is 2.5 - 5 h.

[0021] Furthermore, in step 2), the sodium hydroxide solution is a dilute solution, for example, the concentration can be 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, preferably 20 - 35 wt%.

[0022] Furthermore, in step 2), the sodium hydroxide solution is preferably added dropwise.

[0023] Further, in step 2), the molar ratio of sodium hydroxide to 1,3 - diisopropylbenzene is (2 - 2.4):1.

[0024] Further, in step 2), the reaction temperature is 40°C - 55°C, such as 40°C, 45°C, 50°C, 55°C. Within this temperature range, the reaction time is generally 30 min - 2 h, such as 30 min, 1 h, 1.5 h, 2 h.

[0025] Further, in step 3), the filter cake is washed with water to remove by - product salts and excessive sodium hydroxide.

[0026] Further, in step 3), the drying temperature is 60°C - 70°C.

[0027] The present invention has the following beneficial effects:

[0028] (1) The present invention provides a new reaction route for the synthesis of α,α’ - dihydroxy - 1,3 - diisopropylbenzene. Compared with the traditional air (or oxygen) oxidation method, the present invention reduces the reduction process, has a higher conversion rate, and the obtained target product has better quality.

[0029] (2) The present invention uses a nitrogen - containing organic base as the catalyst and acid - binding agent in the first - step reaction. On the one hand, the organic base can activate the tertiary hydrogen on the diisopropylbenzene side chain, promote the departure of hydrogen ions, and improve the reaction activity; on the other hand, the organic base can act as an acid - binding agent to capture the hydrogen chloride generated in the reaction, promote the forward reaction of the reaction, and make the reaction more complete. The presence of the organic base not only improves the reaction efficiency but also improves the reaction yield.

[0030] (3) The present invention uses an aqueous sodium hydroxide solution as the raw material for the second - step reaction, with a low reaction temperature, mild conditions, short reaction time, and high synthesis efficiency.

[0031] (4) The present invention has high utilization rate of raw materials, few side reactions, no need for high - pressure reaction, less waste water, and high reaction safety.

[0032] (5) The product obtained by the present invention is a white powdery solid, with a product purity ≥ 99% and a yield ≥ 92%. It has good quality, meets the usage requirements, and has industrial application value. Specific embodiments

[0033] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0034] Unless otherwise specified, the following concentrations are all mass percentages.

[0035] In the following examples and comparative examples, the calculation formula for the product yield is as follows:

[0036]

[0037] Example 1

[0038] A new method for preparing α,α'-dihydroxy-1,3-diisopropylbenzene, the reaction equation is as follows:

[0039]

[0040] The reaction includes the following steps:

[0041] 1) Put 100 g of diisopropylbenzene and 130.95 g of triethylamine into a dry and clean reaction kettle, lower the temperature of the reaction kettle to 10 °C, slowly introduce chlorine gas into the bottom of the reaction kettle under ultraviolet light irradiation with a wavelength of 350 - 365 nm and continuously stir, and keep the temperature of the reaction system at 10 °C - 15 °C and the pressure ≤ 0.1 Mpa. The reaction kettle is connected to a tail gas absorption device to absorb the overflowing chlorine gas. Continuously introduce chlorine gas into the reaction kettle. After reacting for 3 h, the total mass of the reaction materials in the reaction kettle increases by 40 g. Stop introducing chlorine gas, and the reaction is completed to obtain a mixed solution A.

[0042] 2) Heat the obtained mixed solution A to 40 °C, then dropwise add 180.77 g of an aqueous sodium hydroxide solution with a mass fraction of 30%, and react at 45 °C - 50 °C for 1 h to obtain a mixed solution B;

[0043] 3) Filter the obtained mixed solution B, wash the filter cake with water, and dry it at 65 °C to obtain 113.73 g of the final α,α'-dihydroxy-1,3-diisopropylbenzene (DC) product.

[0044] After detection and measurement, the purity (GC) of the obtained α,α'-dihydroxy-1,3-diisopropylbenzene is 99.66%, the yield (calculated based on 1,3-diisopropylbenzene) is 94.7%, and the appearance is a white powdery solid.

[0045] Example 2

[0046] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that: in step 1), 130.95 g of triethylamine was replaced by 102.37 g of pyridine.

[0047] After detection and measurement, the purity (GC) of the obtained α,α'-dihydroxy-1,3-diisopropylbenzene was 99.21%, the yield (based on 1,3-diisopropylbenzene) was 94.0%, and the appearance was a white powdery solid.

[0048] Example 3

[0049] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that: 130.95 g of triethylamine was replaced by 44.92 g of hexamethylenetetramine.

[0050] After detection and measurement, the purity (GC) of the obtained α,α'-dihydroxy-1,3-diisopropylbenzene was 99.37%, the yield (based on 1,3-diisopropylbenzene) was 93.5%, and the appearance was a white powdery solid.

[0051] Example 4

[0052] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that: in step 1), the reaction temperature was 5 °C to 10 °C.

[0053] After detection and measurement, the purity (GC) of the obtained α,α'-dihydroxy-1,3-diisopropylbenzene was 99.04%, the yield (based on 1,3-diisopropylbenzene) was 92.8%, and the appearance was a white powdery solid.

[0054] Example 5

[0055] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that: in step 1), 130.95 g of triethylamine was replaced by 137.19 g of triethylamine.

[0056] After detection and measurement, the purity (GC) of the obtained α,α'-dihydroxy-1,3-diisopropylbenzene was 99.42%, the yield (based on 1,3-diisopropylbenzene) was 93.9%, and the appearance was a white powdery solid.

[0057] Example 6

[0058] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that: in step 2), "react at 45 °C to 50 °C for 1 h" was replaced by "react at 50 °C to 55 °C for 1 h".

[0059] After detection and measurement, the purity (GC) of α,α'-dihydroxy-1,3-diisopropylbenzene obtained was 99.15%, the yield (based on 1,3-diisopropylbenzene) was 93.6%, and the appearance was a white powdery solid.

[0060] Example 7

[0061] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that in step 2), 180.77 g of a 30% sodium hydroxide aqueous solution was replaced with 271.15 g of a 20% sodium hydroxide aqueous solution.

[0062] After detection and measurement, the purity (GC) of α,α'-dihydroxy-1,3-diisopropylbenzene obtained was 99.04%, the yield (based on 1,3-diisopropylbenzene) was 92.7%, and the appearance was a white powdery solid.

[0063] Comparative Example 1

[0064] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that in step 1), "lower the temperature of the reaction kettle to 10°C, slowly introduce chlorine gas into the bottom of the reaction kettle under ultraviolet light irradiation with a wavelength of 350 - 365 nm and continuously stir, and maintain the temperature of the reaction system at 10°C - 15°C and the pressure ≤ 0.1 Mpa." was replaced with "at room temperature, slowly introduce chlorine gas into the bottom of the reaction kettle under ultraviolet light irradiation with a wavelength of 350 - 365 nm and continuously stir, and maintain the temperature of the reaction system at 25°C - 30°C and the pressure ≤ 0.1 Mpa."

[0065] After detection and measurement, the purity (GC) of α,α'-dihydroxy-1,3-diisopropylbenzene obtained was 93.54%, the yield (based on 1,3-diisopropylbenzene) was 86.3%, and the appearance was a white powdery solid.

[0066] Comparative Example 2

[0067] α,α'-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that in step 1), "continuously introduce chlorine gas into the reaction kettle, after reacting for 3 h, the total mass of the reaction materials in the reaction kettle increased by 40 g, and stop introducing chlorine gas" was replaced with "continuously introduce chlorine gas into the reaction kettle, after reacting for 2 h, the total mass of the reaction materials in the reaction kettle increased by 25 g, and stop introducing chlorine gas".

[0068] After detection and measurement, the purity (GC) of α,α'-dihydroxy-1,3-diisopropylbenzene obtained was 92.86%, the yield (based on 1,3-diisopropylbenzene) was 82.6%, and the appearance was a white powdery solid.

[0069] Comparative Example 3

[0070] α,α’-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that in step 1), triethylamine was not added.

[0071] After detection and measurement, the purity (GC) of the obtained α,α’-dihydroxy-1,3-diisopropylbenzene was 88.12%, the yield (based on 1,3-diisopropylbenzene) was 68.0%, and the appearance was a white powdery solid.

[0072] Comparative Example 4

[0073] α,α’-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that in step 1), 130.95 g of triethylamine was replaced with 68.59 g of sodium carbonate.

[0074] After detection and measurement, the purity (GC) of the obtained α,α’-dihydroxy-1,3-diisopropylbenzene was 99.01%, the yield (based on 1,3-diisopropylbenzene) was 83.7%, and the appearance was a white powdery solid.

[0075] Comparative Example 5

[0076] α,α’-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that in step 2), “the obtained mixed solution A was heated to 40 °C, and then 180.77 g of a 30% by mass aqueous sodium hydroxide solution was added dropwise thereto, and the reaction was carried out at 45 °C to 50 °C for 1 h” was replaced with “the obtained mixed solution A was heated to room temperature, and then 180.77 g of a 30% by mass aqueous sodium hydroxide solution was added dropwise thereto, and the reaction was carried out at 25 °C to 30 °C for 1 h”.

[0077] After detection and measurement, the purity (GC) of the obtained α,α’-dihydroxy-1,3-diisopropylbenzene was 97.96%, the yield (based on 1,3-diisopropylbenzene) was 87.7%, and the appearance was a white powdery solid.

[0078] Comparative Example 6

[0079] α,α’-Dihydroxy-1,3-diisopropylbenzene was prepared according to the method of Example 1, except that in step 2), “180.77 g of a 30% by mass aqueous sodium hydroxide solution” was replaced with 108.46 g of a 50% by mass aqueous sodium hydroxide solution.

[0080] After detection and measurement, the purity (GC) of the obtained α,α’-dihydroxy-1,3-diisopropylbenzene was 98.74%, the yield (based on 1,3-diisopropylbenzene) was 88.4%, and the appearance was a light yellowish green powdery solid.

[0081] The above embodiments are only used to help understand the method of the present invention and its core idea. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing α,α'-dihydroxy-1,3-diisopropylbenzene, characterized in that It includes the following steps: 1) Conduct a substitution reaction of 1,3 - diisopropylbenzene and chlorine gas under an acid-binding agent and ultraviolet light irradiation; 2) Add a sodium hydroxide solution to the reaction product of step 1) for reaction; 3) Filter the reaction solution of step 2), wash and dry the obtained filter cake to obtain α,α’ - dihydroxy - 1,3 - diisopropylbenzene.

2. The method according to claim 1, characterized in that: In step 1), the acid-binding agent is a nitrogen-containing organic base; preferably, the acid-binding agent is at least one of triethylamine, pyridine, and hexamethylenetetramine.

3. The method according to claim 2, wherein: In step 1), the molar ratio of 1,3 - diisopropylbenzene to nitrogen in the organic base is 1:(2 - 2.2).

4. The method according to claim 1, characterized in that: In step 1), chlorine gas is continuously introduced into the mixture of 1,3 - diisopropylbenzene and the acid-binding agent, and the pressure of chlorine gas in the system ≤ 0.1 Mpa.

5. The method according to claim 1, characterized in that: In step 1), the wavelength of the ultraviolet light is 350 - 365 nm.

6. The method according to claim 1, characterized in that: In step 1), the reaction temperature is 0°C - 20°C.

7. The method according to claim 1 or 6, characterized in that: In step 1), when the mass gain of the reaction system is 40% or more of the mass of 1,3 - diisopropylbenzene, stop introducing chlorine gas.

8. The method according to claim 1, characterized in that: In step 2), the molar ratio of sodium hydroxide to 1,3 - diisopropylbenzene is (2 - 2.4):

1.

9. The method according to claim 1 or 8, characterized in that: In step 2), the mass fraction of the sodium hydroxide solution is 20% - 35%.

10. The method according to claim 1 or 8, characterized in that: In step 2), the reaction temperature is 40°C - 55°C, and the reaction time is 30 min - 2 h.

Images