阅读说明：本技术 一种绿色清洁的对甲氧基肉桂酸异辛酯生产工艺 (green and clean production process of isooctyl p-methoxycinnamate ) 是由 刘启发 王荣 杨健 王中孝 李娟� 于 2018-09-18 设计创作，主要内容包括：本发明涉及一种绿色清洁的对甲氧基肉桂酸异辛酯生产工艺,该工艺包括以下步骤：将乙酸异辛酯与对甲氧基苯甲醛溶于溶剂中,在催化剂作用下反应,生成对甲氧基肉桂酸异辛酯；对生产废水进行处理,回收副产物。本发明中废水处理,有效的将OMC废水转化为有用的EHA、OMC以及符合国标的工业无水硫酸钠,实现了OMC废水的资源化处理,实现了OMC绿色清洁化生产,无反应损失,可循环进行OMC的生产,大大降低了OMC的制造成本。(The invention relates to a green and clean production process of isooctyl p-methoxycinnamate, which comprises the following steps: dissolving isooctyl acetate and p-methoxybenzaldehyde in a solvent, and reacting under the action of a catalyst to generate isooctyl p-methoxycinnamate; the production wastewater is treated, and byproducts are recovered. The wastewater treatment of the invention effectively converts the OMC wastewater into useful EHA, OMC and industrial anhydrous sodium sulfate meeting the national standard, realizes the resource treatment of the OMC wastewater, realizes the green and clean production of the OMC, has no reaction loss, can circularly carry out the production of the OMC, and greatly reduces the manufacturing cost of the OMC.)

1. A production process of isooctyl p-methoxycinnamate is characterized by comprising the following steps:

Step 1), enabling isooctyl acetate to react with p-methoxybenzaldehyde under the action of a catalyst to generate isooctyl p-methoxycinnamate;

And 2) treating the production wastewater, and recovering byproducts.

2. The production process according to claim 1, wherein the molar ratio of isooctyl acetate to p-methoxybenzaldehyde in step 1) is 10: (1.5 to 3.5), preferably 10: (2.0-3.0).

3. The process according to claim 1, wherein in step 1), no reaction solvent is added.

4. The production process according to claim 1, characterized in that step 2) comprises the following sub-steps:

Step 2-1), alkalizing and dewatering: adjusting the pH value of the production wastewater to 7-8 to convert organic matters into corresponding organic salts, adding isooctanol into the system, and refluxing to separate water until no water is separated out;

step 2-2), esterification: adjusting the reaction system to be acidic by inorganic acid to acidify the organic salt and generate inorganic salt, and carrying out esterification reaction under the action of a catalyst; after the reaction is finished, adding water to completely dissolve inorganic salt solids, and separating to obtain a water layer and an oil layer;

Step 2-3), carrying out post-treatment on the water layer to obtain an inorganic salt finished product; the oil layer was transferred to the isooctyl acetate preparation procedure.

5. The production process according to claim 4, wherein in step 2-1), the pH of the wastewater is adjusted with a water-soluble inorganic basic compound,

The water-soluble inorganic alkaline compound is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate, and is preferably sodium hydroxide.

6. the production process according to claim 4, wherein in step 2-2), the inorganic acid is concentrated sulfuric acid;

the catalyst is concentrated sulfuric acid.

7. the production process according to claim 4, wherein in the step 2-2), the esterification reaction is carried out by refluxing and dividing water at 130-150 ℃ until acetic acid residue (area normalization) is less than 0.2% in GC detection.

8. The production process according to claim 4, wherein in the step 2-2), after the reaction is finished, the water in which the inorganic salt solid is completely dissolved is the water extracted in the step 2-1) of alkalization and water removal;

The step 2-2) also comprises a step of adding isooctanol into the water layer obtained by final separation for extraction, and an oil layer obtained by extraction separation is transferred to an alkalization dewatering process.

9. The production process according to claim 4, wherein in the step 2-3), the post-treatment of the aqueous layer is: distilling part of water from the obtained water layer under normal pressure, cooling, crystallizing, filtering, and drying in vacuum to obtain an inorganic salt finished product;

The separated oil layer was transferred to the preparation of isooctyl acetate.

10. the production process according to claim 4, wherein when the pH of the wastewater is adjusted with sodium hydroxide in 2-1) and the inorganic acid is sulfuric acid in step 2-2), the recovered by-product comprises sodium sulfate,

The anhydrous sodium sulfate is a white solid, the mass fraction of the sodium sulfate is not less than 98.0%, the mass fraction of water is not more than 1.0%, the mass fraction of water-insoluble substances is not more than 0.01%, and the mass fraction of chloride (calculated as Cl < - >) is not more than 0.037%.

Technical Field

The invention belongs to the technical field of daily chemical industry, relates to a production process of a sun-screening agent, and particularly relates to a green clean production process of a sun-screening agent isooctyl p-methoxycinnamate.

Background

Isooctyl p-methoxycinnamate (OMC) is one of the most commonly used sun-screening agents in the world at present, is a good ultraviolet absorbent in a UVB region, can effectively prevent ultraviolet rays of 280-330nm, has high absorptivity, no stimulation to skin, good safety and good solubility to the solubility of oily raw materials, is almost an ideal sun-screening agent, and is widely applied to the fields of daily chemicals, plastics, rubber, coatings and the like.

the synthesis process of isooctyl p-methoxycinnamate is mainly obtained by esterification (ester exchange) reaction of p-methoxycinnamate and isooctyl alcohol, such as preparation by the following routes:

Two-step processes are commonly used in industry: the first step, p-methoxy cinnamic acid (CN 102060832; Asian J.chem.2007,19(6): 4945-; and secondly, esterifying the p-methoxy cinnamic acid and isooctyl alcohol to obtain the isooctyl p-methoxy cinnamate. The process has the advantages of more steps, higher reaction temperature, yield less than 70 percent and capability of generating a large amount of useless NaCl and dilute acetic acid. Meanwhile, a large amount of acetate, carbonate and inorganic acid are used in the reaction process, so that a large amount of wastewater with high salt and high COD value is generated, and serious problems are brought to pollution treatment.

Prepared by Knoevenagel reaction using p-methoxybenzaldehyde as a raw material (bioorg.Med.chem.2011,19(10): 3192-4-3203; Chin.chem.Lett.2011,22(6), 667-sand 670; Chin.chem.Lett.2009,20(3):279 282; J.Agric.food chem.2009, 57(8): 3261-sand 3265; Med.chem.2007,3(5): 475-sand 479; Tetrahedron Lett.2007,48(26): 4505-sand 4508; Eur.J.Pharm.Sci.2004,23(4-5): 363-369; Proc.2002; 28-32; J.Fluor. chem.159, 48-67; Zyh.19881; Het.19881-5): 92; Eur.19881-19851-sand 51-sand; Eur.1984: 27; Eur.1988; Het.19881, 24-19851-sand) (J.19851-sand) (1988): p-methoxy cinnamic acid is prepared by taking p-methoxy benzaldehyde, malonic acid and derivatives thereof as raw materials under the action of catalysis such as pyridine, and after the reaction is finished, acid water is needed to wash and remove catalyst piperidine, so that a large amount of waste water is undoubtedly generated by the operations, and the environment is seriously polluted. Then, preparing OMC by esterifying the obtained product with isooctyl alcohol; however, malonic acid and its derivatives are expensive, and the catalysts used, such as pyridine, have a strong odor and strong toxicity, which all limit the possibility of applying the method to industrial production.

the p-methoxybenzaldehyde is used as a raw material to prepare the compound through a Claison-Schmidt reaction (CN 1218794; CN 1170401; CN 102627559;): p-methoxybenzaldehyde and methyl acetate are used as raw materials, strong base such as sodium methoxide is used as a catalyst for reaction, then hydrochloric acid or sulfuric acid is used for acidification to obtain p-methoxycinnamic acid methyl ester, and then the p-methoxycinnamic acid methyl ester and isooctyl alcohol are subjected to ester exchange reaction under the action of the catalyst such as sodium carbonate to obtain OMC. After the reaction is finished, a large amount of water is needed to wash the materials, so that the generated high-salt and high-COD wastewater brings pressure to environmental protection treatment and causes pollution to the surrounding environment.

in conclusion, the method for producing isooctyl p-methoxycinnamate in the prior art inevitably generates a large amount of waste, causes the risk of environmental pollution, has the problems of single reaction route and expensive reaction raw materials, and is not beneficial to industrialization.

Disclosure of Invention

the inventor provides a brand-new industrialized synthesis method of isooctyl p-methoxycinnamate, which takes p-methoxybenzaldehyde, acetic acid, isooctyl alcohol (EH) and the like as raw materials to synthesize a sunscreen OMC through the procedures of esterification, condensation, rectification and the like; then carrying out resource treatment on the OMC wastewater: converting sodium acetate in the wastewater into raw material isooctyl acetate required for preparing OMC by related chemical reaction and separation method, and simultaneously obtaining industrial anhydrous sodium sulfate (Na2SO4) meeting national standard; by-products such as p-methoxycinnamic acid, methyl p-methoxycinnamate, methyl acetate and the like in the wastewater are converted into products OMC, so that the green production of OMC is realized, the manufacturing cost of OMC is greatly reduced, and the invention is completed.

The invention aims to provide the following technical scheme:

(1) A production process of isooctyl p-methoxycinnamate comprises the following steps:

Step 1), enabling isooctyl acetate to react with p-methoxybenzaldehyde under the action of a catalyst to generate isooctyl p-methoxycinnamate;

And 2) treating the production wastewater, and recovering byproducts.

The production process of isooctyl p-methoxycinnamate provided by the invention has the following beneficial effects:

(1) the OMC wastewater recycling treatment scheme adopted by the invention can completely convert sodium salts in various forms in wastewater generated in the OMC washing procedure of a factory into anhydrous sodium sulfate meeting the standards of industrial sodium sulfate III class first-class products, thereby greatly reducing the pollution of waste salts to the environment;

(2) The OMC wastewater recycling treatment scheme adopted by the invention can completely recover acetic acid, thereby avoiding the waste of acetic acid, improving the utilization rate of acetic acid and greatly reducing the pollution to the environment;

(3) The OMC wastewater recycling treatment scheme adopted by the invention can completely recover byproducts such as p-methoxycinnamic acid, methyl p-methoxycinnamate, methyl acetate and the like generated in the OMC condensation reaction process, so that the byproducts are finally converted into the required product OMC, thereby increasing the yield of OMC and reducing the pollution of the byproducts to the environment;

(4) The method adopts the OMC wastewater recycling treatment scheme, the obtained anhydrous sodium sulfate can be sold, acetic acid and various byproducts are completely recovered in the forms of EHA and OMC, the OMC yield is greatly improved, and the OMC manufacturing cost is greatly reduced. Meanwhile, the process adopts a closed circulation mode, and various process water, mother liquor and the like are circularly applied, so that the pollution to the environment is greatly reduced, and the process is a green and clean resource treatment process;

(5) the invention also has the characteristics of simple operation, easy control and easy realization of industrial production.

Drawings

FIG. 1 shows a schematic flow diagram for resource treatment of OMC wastewater;

Figure 2 shows the finished sodium sulfate product obtained in example 1.

Detailed Description

The invention aims to provide a production process for preparing isooctyl p-methoxycinnamate, which comprises the following steps:

Step 1), enabling isooctyl acetate to react with p-methoxybenzaldehyde under the action of a catalyst to generate isooctyl p-methoxycinnamate;

And 2) treating the production wastewater, and recovering byproducts.

the present invention is specifically described below.

Step 1), isooctyl acetate and p-methoxybenzaldehyde react under the action of a catalyst to generate isooctyl p-methoxycinnamate. The reaction formula is shown in the following formula (1):

In the invention, the isooctyl acetate is obtained by condensing isooctyl acetate and acetic acid, and the reaction formula is shown as the following formula (2):

In step 1) of the present invention, the catalyst is selected from sodium or potassium alkoxides, such as sodium methoxide, potassium methoxide, preferably sodium methoxide.

Preferably, the dosage of the catalyst is (0.8-1.3) in terms of the molar ratio of the catalyst to p-methoxybenzaldehyde: 1, preferably (1-1.1): 1.

more preferably, the catalyst is a solid catalyst and is added to the reaction system in batches, for example, 2 to 5 times.

In step 1) of the present invention, the molar ratio of the isooctyl acetate to the p-methoxybenzaldehyde is 10: (1.5 to 3.5), preferably 10: (2.0-3.0).

In order to promote the reaction, a reaction raw material excess is selected, and due to the decomposition of isooctyl acetate under alkaline conditions, an excess of isooctyl acetate is preferred in the present invention. When the dosage ratio is more than 10:1.5, the isooctyl acetate is seriously excessive, and the residual isooctyl acetate is decomposed under the alkaline condition and cannot be recycled, so that the load of post-treatment is increased; the dosage ratio is less than 10:3.5, p-methoxybenzaldehyde remains after the reaction is finished, the conversion rate of raw materials is low, and the yield is low.

In the step 1) of the invention, at a set low temperature, a catalyst is added into isooctyl acetate, then p-methoxybenzaldehyde is dropwise added into the reaction system, and after the dropwise addition is finished, the temperature is raised for a set time. The reaction of step 1) is carried out with stirring.

Wherein the low temperature is set to be 20-25 ℃;

After the dropwise addition is finished, the temperature rise is 100-155 ℃, and preferably 110-135 ℃; the reaction time after the temperature rise is 0.5 to 3 hours, preferably 1 to 2 hours. Under the temperature condition, the reaction does not generate more byproducts too violently, and the reaction speed is ensured.

In step 1) of the present invention, no reaction solvent is added during the reaction.

In the step 1), after the reaction is finished, adding water into the reaction system, stirring, standing, and layering to obtain a water layer and an organic layer.

And (3) washing the organic layer, separating the water layer to obtain a washed organic layer, and rectifying the organic layer to obtain a finished product of isooctyl p-methoxycinnamate, isooctanol and non-target fractions (methyl methoxycinnamate and methyl acetate).

And combining all the separated water layers with non-target fractions for subsequent production wastewater treatment.

and 2) treating the production wastewater, and recovering byproducts.

the inventor finds that the synthesis of isooctyl p-methoxycinnamate can be effectively realized in the step 1), but the following disadvantages exist:

(i) The utilization rate of the reaction raw material isooctyl acetate is not high and is only 30%: synthesizing OMC from isooctyl acetate and p-methoxybenzaldehyde under the action of sodium methoxide as catalyst, and decomposing isooctyl acetate in about 66.6% into isooctyl alcohol while recovering isooctyl alcohol, but consuming the acetic acid to convert into sodium acetate and unable to recover;

(ii) Side reactions occur in the condensation reaction, and byproducts such as p-methoxycinnamic acid (product decomposition), methyl p-methoxycinnamate, methyl acetate and the like cannot be recycled. After the esterification and condensation reactions are finished, a large amount of water is needed to wash materials, so that the generated high-salt and high-COD wastewater brings pressure to environmental protection treatment and causes pollution risk to the surrounding environment.

Therefore, the invention has carried on a large amount of studies, carry on the resource treatment to OMC waste water, its core thought is, through the relevant chemical reaction and separation method, change sodium acetate in the waste water into raw materials acetic acid isooctyl ester that OMC needs, and obtain the industrial anhydrous sodium sulfate meeting national standard at the same time; by-products such as p-methoxycinnamic acid, methyl p-methoxycinnamate, methyl acetate and the like in the wastewater are converted into products OMC, the OMC yield is improved, and the environment-friendly production of OMC is realized.

specifically, step 2) includes the following substeps:

Step 2-1), alkalizing and dewatering: adjusting the pH value of the production wastewater to 7-8 to convert organic matters into corresponding organic salts, adding isooctanol into the system, and refluxing to separate water until no water is separated out;

step 2-2), esterification: adjusting the reaction system to be acidic by inorganic acid so as to acidify the organic salt and generate inorganic salt (acid-base neutralization), and carrying out esterification reaction under the action of a catalyst; after the reaction is finished, adding water to completely dissolve inorganic salt solids, and separating to obtain a water layer and an oil layer;

Step 2-3), carrying out post-treatment on the water layer to obtain an inorganic salt finished product; the oil layer was transferred to the EHA preparation procedure.

The flow chart of the wastewater treatment process of the step 2) is shown in figure 1.

in the step 2-1) of the invention, the pH value of the wastewater is adjusted by using a water-soluble inorganic alkaline compound, so that organic matters (such as p-methoxycinnamic acid, methyl p-methoxycinnamate and methyl acetate) in the wastewater are completely converted into water-soluble salts such as acetate and p-methoxycinnamate.

Wherein, the water-soluble inorganic alkaline compound is selected from one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate, and is preferably sodium hydroxide.

In the step 2-1), the water-soluble inorganic alkaline compound is added to convert organic matters (such as p-methoxycinnamic acid, methyl p-methoxycinnamate and methyl acetate) into corresponding organic salts (such as acetate and p-methoxycinnamate), so that the problem that low-boiling-point organic acetic acid cannot participate in subsequent esterification reaction along with water vapor escape is effectively avoided. Methanol generated by decomposing methyl p-methoxycinnamate and methyl acetate is distilled out along with water vapor in the reflux process, and is treated intensively (such as distillation to respectively obtain methanol and water).

In the invention, isooctyl alcohol is used as a water-bearing solvent and is added into a reaction system as a raw material for subsequent esterification reaction. Isooctanol is the raw material of isooctyl p-methoxycinnamate, and compared with other water-bearing solvents or alcohol esterification reaction raw materials, the load and the cost of the treatment of the production wastewater are reduced.

in step 2-2), inorganic acid is used for adjusting the pH value of the mixture qualified for dewatering to 1-2, organic salt such as acetate and p-methoxycinnamate is acidified and converted into acetic acid and p-methoxycinnamic acid, sodium sulfate is generated, esterification reaction is carried out under the action of catalyst, acetic acid and p-methoxycinnamic acid are reacted with isooctyl alcohol and converted into EHA and OMC, and the reaction is finished.

Wherein the inorganic acid is concentrated sulfuric acid; the catalyst is concentrated sulfuric acid. The concentrated sulfuric acid has the dual functions of a pH regulator and a catalyst, so that the purity and the yield of inorganic salt products are high; the pH regulator is concentrated sulfuric acid, does not introduce water, and is beneficial to the esterification reaction.

In the step 2-2), the esterification reaction is carried out by refluxing and water dividing at 130-150 ℃ until the acetic acid residue (area normalization) is less than 0.2% during GC detection.

In the step 2-2), after the reaction is finished, the water extracted in the step 2-1) alkalization water removal process is adopted to completely dissolve the inorganic salt solid, and exogenous water is not added to dissolve the inorganic salt solid, so that the closed cycle mode of the process is embodied, the process water is recycled, and the pollution to the environment is greatly reduced.

in step 2-2), the method further comprises the following steps: adding isooctanol into the water layer obtained by final separation, stirring, standing, separating an oil layer (the main component is still isooctanol), and transferring into an alkalization dewatering process.

The purpose of adding isooctanol into the water layer is to further extract organic matters in the water layer and reduce the content of organic impurities in the water layer so as to obtain high-purity inorganic salt. And carrying out post-treatment on the extracted water layer to obtain inorganic salt.

In step 2-3) of the present invention, the post-treatment of the aqueous layer means: distilling part of water out of the obtained water layer under normal pressure, cooling, crystallizing, filtering, and drying in vacuum to obtain the inorganic salt finished product.

in the step 2-3), when water accounting for 50-55% of the total weight is distilled out by normal pressure distillation, the distillation is stopped, the temperature is reduced to 40-50 ℃, the stirring is maintained for 20-40 min, the filtration is carried out, and the filtrate is applied to the step 2-1) of alkalization dewatering process.

In the step 2-3), the filter cake is dried at 140-155 ℃ to obtain white solid anhydrous sodium sulfate.

In particular, in the anhydrous sodium sulfate, the mass fraction of sodium sulfate is not less than 98.0%, the mass fraction of moisture is not more than 1.0%, the mass fraction of water-insoluble substances is not more than 0.01%, and the mass fraction of chloride (calculated as Cl < - >) is not more than 0.037%, so that the prepared sodium sulfate meets the first-class standard of industrial sodium sulfate III.

In step 2-3) of the present invention, the separated oil layer is transferred to the EHA production process.

the oil layer contained unreacted isooctyl alcohol, EHA, OMC, and a small amount of acetic acid. Transferring the oil layer to an EHA preparation process, generating EHA by using isooctanol and acetic acid, and further carrying out the synthesis of isooctyl p-methoxycinnamate again.

The method is used for reacting to generate isooctyl acetate or isooctanol added in the step 2), and is obtained by preparing octenal (2-ethyl-2-hexenal) by self-condensation of n-butyl aldehyde and hydrogenating the octenal, wherein the preparation of the octenal comprises the following steps:

step A), adding potassium hydroxide into n-butyraldehyde, and reacting under the catalysis of the potassium hydroxide;

And B), after the reaction is finished, adding acetic acid for neutralization, carrying out heat preservation reaction, and carrying out post-treatment to obtain the octenal.

In step A) of the present invention, the catalyst potassium hydroxide is added to the reaction system in solid form. Although there are reports in the prior art that the form of the catalyst includes liquid inorganic base, liquid organic base, solid inorganic base and solid organic base, as part of the system of the present invention, we find that the catalyst participates in the reaction in the form of solid inorganic base, which is beneficial to improve the selectivity of the product octenal and the conversion rate of n-butyraldehyde as a raw material of the reaction compared with other liquid bases and solid organic bases, and the inorganic base reduces the introduction of impurities in the product compared with the organic base.

In step a) of the present invention, the solvent is a polar protic solvent, preferably methanol or ethanol, more preferably methanol. After the reaction is finished, the product comprises a water phase and an oil phase, and when the water phase is alcohol-water, the ethanol and the water can be subjected to azeotropic distillation and are not easy to separate; methanol and water do not have azeotropy and are easy to separate.

Further, the amount of methanol is 1: (2-4), preferably 1: (2.5-3.5).

In step A) of the present invention, the amount of potassium hydroxide is such that the weight ratio of potassium hydroxide to n-butyraldehyde is 1: (60 to 150), preferably 1: (80-120).

the weight ratio of potassium hydroxide to n-butyraldehyde is less than 1: at 150 ℃, the alkali concentration is too low, the condensation reaction is not complete, and the conversion rate of n-butyraldehyde is low; however, when the weight ratio of potassium hydroxide to n-butyraldehyde is higher than 1: at 60 hours, if the concentration of the alkali is too high, the condensation reaction is more severe, so that a trimer or a polymer is easily generated, and a large amount of byproducts are generated, so that the selectivity of the octenal is low.

in the invention, the set temperature is 120-155 ℃, preferably 135-140 ℃; the reaction time is 1.0-3.5 h, preferably 1.5-3.0 h.

In step B) of the present invention, acetic acid is added to neutralize the catalyst potassium hydroxide. Wherein the molar ratio of acetic acid to potassium hydroxide is 1: 1.

In the step B), the reaction is carried out for 2 to 3.5 hours at the temperature of 120 to 155 ℃, preferably for 2.5 to 3.0 hours at the temperature of 135 to 140 ℃.

Although the reaction stage of the step B) is not the main generation stage of the target product, part of n-butyraldehyde still does not participate in the reaction after the reaction stage of the step A) is completed, so that the reaction stage of the step B) is still very related to the conversion rate of the n-butyraldehyde and the selectivity of the target product.

in the step B), the conversion of the residual n-butyraldehyde can be smoothly completed without additionally adding potassium hydroxide. After the reaction stage of the step A) is finished, acetic acid reacts with potassium hydroxide in an equivalent weight for neutralization reaction to generate corresponding potassium acetate. It is found that the potassium salt has the same catalytic effect as potassium hydroxide, but if strong alkali such as sodium hydroxide is used as the catalyst in the reaction stage of the step A), the sodium salt obtained after neutralizing the strong alkali does not have the corresponding catalytic function.

Meanwhile, if the step B) is not carried out, after the reaction in the step A) is finished, the conversion rate of n-butyraldehyde is influenced, a large amount of water is added to wash reaction products, the discharge amount of alkali-containing wastewater is large, high treatment cost is needed to prevent the environment pollution, a large amount of acid liquor is consumed for treating wastewater, and the production cost is increased.

And B), acetic acid is added in the step B), so that the separated wastewater is neutral wastewater, additional acid is not needed, the cost is increased, and potassium acetate in the wastewater can be recycled.