Production Technology Of Epoxy Soybean Oil
With the rapid development of plastic industry, the demand for plasticizer is more and more. At the same time, in recent years, with the increase of people's awareness of environmental protection, plastic additives also put forward a higher health requirements. Because the commonly used plasticizer phthalate esters have potential carcinogenic risk, it is a hot spot to develop new non-toxic plasticizer. Epoxy soybean oil is a newly developed non-toxic Plasticizer, which has a wide prospect in plastics, especially in the processing of polyvinyl chloride.
Properties and applications of epoxy soybean oil
Epoxy soybean oil is a chemical product made by using peroxide treatment of refined soybean oil, the English name is Epoxidizedsoy-beanoil (ESO), molecular formula c57h98o12, molecular weight is about 1000. At room temperature for light yellow viscous oil-like liquid, flow Point-1 ℃, boiling point 150 ℃ (0.5kPa), ignition points 310 ℃, viscosity 325mpa?s (25 ℃), refractive index 1.4713 (25 ℃). Soluble in hydrocarbons, ketones, esters, advanced alcohols and other organic solvents. Slightly soluble in ethanol, insoluble in water.
Epoxy soybean oil because of its good heat resistance, light, mutual permeability, low softness and toughness, and low volatility, no toxicity, so the application is quite extensive, especially for food and drug plastic packaging materials plasticizer. Epoxy soybean oil is widely used in PVC processing. The epoxy group can trap the free radical cl-by PVC degradation, terminate the free radical reaction of PVC degradation, slow down the degradation rate, improve the light, heat resistance and oil resistance of PVC products, and endow the products with good mechanical strength, weatherability and electrical properties. It not only has plasticizing effect on polyvinyl chloride, but also can make the active chlorine atom in the chain of polyvinyl chloride stable, and can quickly absorb the HCL which is degraded by heat and light, thus blocking the continuous decomposition of polyvinyl chloride and stabilizing the function. In agricultural films, open-air PVC pipes and cable products to add epoxy soybean oil, can make the product heat resistance, light tolerance and good weather resistance. In addition, the compatibility of epoxy soybean oil with PVC is very good, can quickly evenly dispersed in the PVC system, thereby weakening the force between PVC macromolecules, increase the activity between molecules. In the process of PVC processing, as long as the use of a small amount of epoxy soybean oil will reduce the processing energy consumption, improve processing speed, improve operating conditions, improve product surface quality, to reduce costs, improve economic efficiency play a positive role. Epoxy soybean oil and polyester plasticizer can reduce the migration of polyester plasticizer. It has good synergistic effect when used with metal salts stabilizer such as cadmium and zinc. The use of this product can be appropriate to reduce the amount of other plasticizers, stabilizers and lubricants. This productis applicable to all kinds of PVC products, transparent bottles, transparent boxes, a variety of food packaging materials, medical products "blood transfusion bag", a variety of films, sheets, tubes, refrigerator seals, refrigeration equipment and motor vehicles used in gaskets, artificial leather, floor leather, plastic wallpaper, wire and cable and other daily-use plastic products, but also for special inks, Liquid composite Stabilizer. PVC Outdoor plastic products, waterproof membrane, plastic doors and windows, stickers wallpaper, plastic film and so on must use epoxy soybean oil, to ensure that products non-toxic, transparent, heat, low-temperature, toughening, anti-aging and so on. In addition, because of the non-toxic epoxy soy oil, can also be used as food packaging materials, toys and home decoration materials, such as additives.
Production method of 2 epoxy soybean oil
At present, the main production methods of epoxy soybean oil are solvent method and solvent-free method, the main production methods are peracetic acid oxidation, ion exchange resin catalysis, aluminum sulfate catalysis, peracetic acid oxidation and phase transfer catalytic oxidation method.
2.1 Peracetic Acid Oxidation method
The process takes benzene as solvent, sulfuric acid as catalyst, formic acid and hydrogen peroxide to produce peracetic acid in the presence of sulfuric acid, and the epoxidation of soybean oil to produce epoxy soybean oil. The soybean oil, formic acid, sulfuric acid and benzene are put into the reaction kettle according to a certain dosage ratio, stirring and mixing evenly. The 40% (WT) content of hydrogen peroxide is slowly added to the stirring. During the drip process, the reaction temperature is controlled by the cooling water and the adjusting drop acceleration. After the hydrogen peroxide is added, stirring for a period of time, and so on the material temperature in the cooling water does not rise, or even a slight drop, you can stop stirring. Then static stratification, the upper layer for the oil layer, containing products and benzene, the lower layer of waste acid water. After the waste acid water is separated, the oil layer is neutralized and washed with 2%-5% dilute soda liquid, and then washed to neutral. After water separation, the oil layer is distilled, the mixture of benzene and water is separated by condensation, and 80% of benzene can be recycled. The liquid of the kettle is decompressed, and then the finished product is filtered by pressure. The process has fast reaction speed and low temperature, but the process is long and complex, the product quality is unstable, the epoxy value is about 5%, the production cost is high, the equipment is many, the "three-waste" treatment quantity is big, the solvent benzene has certain toxicity. is being gradually replaced by solvent-free methods. 2.2 Peracetic Acid Oxidation method
Formic acid or acetic acid and hydrogen peroxide react to produce the ring oxidant under the action of catalyst sulfuric acid, and add the ring oxidizing agent to soybean oil within a certain temperature range, after the reaction is finished, the product is obtained by alkali washing, water washing and decompression distillation. The production process of this method is short, the reaction temperature is low, the reaction time is short, the by-products are few, the product quality is high, and the production technology of benzene as solvent is basically substituted. Because the molecule of formic acid is smaller than acetic acid, the oxidation rate of peracetic acid is higher than that of peracetic acid, so the quality of the products produced by formic acid is slightly better and the reaction process is shorter. At present, most of the production enterprises use formic acid as the active oxygen carrier of epoxidation, the use of formic acid and some of the acid decomposition of carbon monoxide produced by the toxicity. Dalian Institute of Light and Chemical engineering under the solvent-free conditions, study on the synthesis of epoxy soybean oil by peracetic acid and the influence of the main reaction conditions on the epoxidation, and the technical route, technological process, technological conditions and product quality of the synthesis of epoxy soybean oil by solvent method and solventless method are compared. It is found that the solvent-free method has the advantages of simple production process, no solvent recovery problem, low raw material consumption, short production cycle, product quality reaching the advanced level of domestic similar products, solves the problem of benzene solvent pollution in the production process, and improves the workers ' production environment. At the same time, the Fujian Institute of Chemical Engineering in the Zhangzhou chemical plant, the use of solvent-free one-step epoxidation process, that is, hydrogen peroxide and glacial acetic acid in the presence of the catalyst under the reaction of the formation of acetic acids, acetic acid and refined soybean oil reaction to get epoxy soybean oil. It overcomes the disadvantages of many synthetic steps of benzene as solvent, sulfuric acid as catalyst, high product cost, large amount of "three wastes" treatment and low yield. The thermal stability of epoxy soybean oil plasticizer produced by solvent-free process was improved obviously, and the thermal stability of epoxy (epoxy) was increased from 60%-80% of solvent process to more than 95%, while the problems of "three wastes" pollution and equipment pipeline corrosion were overcome. In addition, the researchers found that using dilute ammonia-hydrogen peroxide to refine the crude oil can reduce the loss of oil, and make the refined oil color better than the edible oil standard; epoxidation reaction without catalyst, using urea as the main component of the stabilizer, the epoxidation reaction time shortened, coarse color is very shallow; Using three times washing and washing to remove the organic acids in the coarse products, replacing the alkali wash-washing process, can greatly reduce the emulsification and loss of crude products, and is beneficial to the stratification of oil-water two-phase. At present, the technology has been used for industrial applications
Catalytic method of 2.3 ion exchange resins
Although the solvent-free method overcomes many deficiencies of the solvents, it also has the disadvantages of poor reaction stability, low epoxy value of products, deep color of product, corrosion of equipment and serious environmental pollution, and substituting cation exchange resin for sulfuric acid as catalyst, peracetic acid or acetic acid as oxidant, The process of synthesizing epoxy soybean oil under solvent-free conditions can overcome these disadvantages. Add soybean oil, ion exchange resin and acetic acid in the reaction kettle, heat up to 70-80 ℃, add hydrogen peroxide in the reaction kettle evenly in 40min, when the temperature rises, the cold water cools and the heat preservation reaction 12-18h. After the reaction is filtered, the ion exchange resin is removed, the static layer is separated, and the oil phase is neutralized with the saturated NaCl solution containing 2%-3% sodium hydroxide to a micro-alkaline (ph value of 8.5-9.0), and then purified with pure water to neutral and chlorine-free ions. 30min, isolate the lower layer. After washing the coarse goods into the distillation kettle, the decompression distillation dehydration can be made of epoxy soybean oil products. The process is characterized by simple process, short production process, low energy consumption, less equipment investment, safe production, good quality of products, no toxic solvents, the deficiency is the cycle time is relatively long. The study found that the cationic resin used can be reused, when the catalyst activity decreased significantly, with 95% ethanol reflux washing and recovery resin 2 hours, washing, drying, and then the resin pretreatment, then the catalytic activity of the resin was restored.
2.4 Aluminum Sulfate Catalysis method
Formic acid and hydrogen peroxide react to produce ring oxidant under the action of the catalyst Aluminum sulfate, then the ring oxidant is added to soybean oil within a certain temperature range, and the epoxy soybean oil is obtained by alkali washing, washing and vacuum distillation after the reaction. The process has high reactiveactivity, easy processing, yield can be as high as 96%, compared with the cation exchange resin catalytic method, the catalyst cost is low, the deficiency is that the catalyst needs to strictly control the content of fe2+, iron content is too high, fe2+ in the presence of hydrogen peroxide is easy to act as a catalyst to accelerate Unfavorable to the progress of the epoxidation reaction. At the same time, the fe2+ also causes the material temperature to rise sharply, difficult to control the epoxidation reaction temperature.
2.5 phase transfer Catalytic oxidation method
Institute of Chemistry and Materials science, Shaanxi Normal University, Deng Fang, etc. in the condition of no carboxylic acid, acetic acid ethyl ester as solvent, methyl tri-octyl hydrogen sulfate as phase transfer catalyst, epoxy soybean oil was synthesized by direct epoxidation of soybean oil with 30% (mass fraction) hydrogen peroxide solution. The experimental results show that the epoxidation of soybean oil can be successfully achieved by hydrogen peroxide in the condition of no carboxylic acid, the epoxy value of the product is 6.27% and the iodine value is 5.80g/100g when the solution ph is 2, the reaction temperature is 60 ℃ and the reaction time is 7h. This method avoids the formation of acid in the reaction, reduces the production of by-products and improves the product quality. Wuya, Institute of Chemistry and Materials science, Shaanxi Normal University the cyclic oxidation reaction of soybean oilwas carried out with the oxygen-tungsten complexes as phase transfer catalysts, and the results showed that the reaction temperature was 60 ℃, the oil riddle was solvent, and the 1,2--pyridine salt (CWP) was used as catalyst. The epoxy value of the reaction product reached 6.4%, and the iodine value was 4.4g/100g. This reaction does not use the dangerous peracetic acid and the strong corrosive sulfuric acid, the product obtains the color to be shallow, the epoxy value is high, the quality is good, but the reuse of the oxygen complex is still awaiting further study.
3 China's epoxy soybean oil development and utilization prospects
The plasticizers used in our country in recent years are phthalate esters. Foreign countries due to DBP volatile loss has been eliminated, DOP due to the United States Cancer Institute (NCI) and the Food Administration (FDA) proposed that may cause cancer, thereby limiting its application. New research shows that phthalates in the environment to escape, into the body or animals will produce mimic estrogen, the male and female animals have effects. From the point of view of environmental protection, its production and application will be limited by environmental regulations. Epoxy soybean oil as non-toxic, plasticized, stable plastic additives, will increasingly cause plastic processing industry and plasticizer production enterprises of high concern. China is rich in oil resources, more varieties, especially soybean oil production in the forefront of countries around the world, which provides raw materials for the development of epoxy soybean oil. In recent years, with the development of the ethylene industry in China, the production of polyvinyl chloride resin has developed rapidly, in 2006 our production capacity of polyvinyl chloride has reached 10.99 million tons, production reached 8.641 million tons, consumption reached 9.594 million tons, the production capacity of 2010 is expected to reach about 14 million tons, Demand will reach about 12.5 million tons, then the demand for plasticizers will also increase significantly, and epoxy soybean oil as a non-toxic plasticizer, its development prospects will be very broad. Therefore, the domestic relevant production enterprises should speed up technological progress, improve the industrialization of epoxy soybean oil production technology, reduce production costs, improve product quality, to meet the plastic processing industry for high-quality, multi-functional plasticizer needs, in order to obtain greater economic benefits.