Acrylic acid and its esters have developed rapidly in recent years and have become important industrial derivatives of propylene, like polypropylene, acrylonitrile, and propylene oxide. Acrylates are mainly methyl acrylate, ethyl acrylate, butyl acrylate, and octyl acrylate.
Until the mid-1970s, acrylic acid was mainly used to produce acrylic esters in the industry, accounting for about 62% of total acrylic acid consumption. It was used in construction, papermaking, leather, textile, plastic processing, packaging materials, daily chemicals, and water. Processing, oil extraction, metallurgy and other fields. In addition, it occupies a very important position in the field of fine chemicals. Polypropylene and acrylic copolymers produced with acrylic acid have traditionally been used only as dispersants, flocculants and thickeners. In the late 1970s, there were two new markets for polypropylene and acrylic copolymers—high water-absorbent resins and detergents, which provided bright prospects for the expansion of acrylics and promoted the acrylic industry. Acrylic acid industry is still an emerging industry in China. Its product chain is a high-tech, high-value-added product with a promising market outlook.
At the end of the 1960s, there were various preparation methods for acrylic acid: cyanohydrin hydrolysis, acrylonitrile hydrolysis, Reppe, and propylene oxidation. After the 1980s, new and expanded installations used propylene two-step oxidation. In this method, propylene is oxidized to acrolein by air in the presence of a composite metal oxide catalyst, and further catalyzed oxidation to acrylic acid. The method for producing acrylic acid depends mainly on the catalyst. The catalysts produced by Nippon Shokubai Chemicals and Mitsubishi Petrochemical Co., Ltd. are widely used due to their high activity, long life, and high mechanical strength. At present, most of the catalysts used in industry are molybdenum-based multi-component catalysts, followed by cobalt, nickel, iron, vanadium, copper, magnesium and other metals. The promoters include iron, arsenic, antimony, etc. The acidic components are Thorium and boron.
In industrial production, acrylates are generally divided into light esters and heavy esters.
Typical light esters are methyl acrylate and ethyl acrylate and can be produced in the same production plant. The heavy esters, butyl acrylate and octyl acrylate, can also be produced in the same apparatus. At present, acrylic acid and alcohol are mostly used in the direct esterification process to produce acrylates. Among them, the production of lighter esters usually uses sulfuric acid or acidic ion exchange resins as esterification catalysts, and the catalysts for the production of heavy esters vary according to the production process and the type of product.
At present, the development trend of acrylic acid and its ester production technology mainly focuses on the improvement of the process and the research of the catalyst. In terms of acrylic acid purification, Japan's Mitsubishi Petrochemical Co., Ltd. has successfully developed a reaction gas absorption tower and a five-tower purification process; Nippon Shokubai Chemical Co., Ltd. has also made effective improvements to the original extractive distillation process; U.S. companies have always been acetic acid-formaldehyde gas phase condensation. Conducted research and made some progress. In addition, on the basis of the traditional Mo-V catalyst, Japan’s Mitsubishi Petrochemical Company has made significant improvements in terms of additives, carriers, and preparation processes, which have resulted in lower reaction temperatures, higher selectivity, and longer catalyst life. Mo-V-Zr composite catalyst was developed by So-hio of the United States for fixed-bed reaction. The yield of acrolein to produce acrylic acid can exceed 95%. Improvements in acrylate synthesis technology are also emerging. For example, the synthesis of butyl acrylate and 2-ethylhexyl ester has shifted to the continuous process.
In the 1990s, the production of acrylic acid and its esters culminated. With the development and popularization of acrylic superabsorbents and household washing aids, companies engaged in the production of acrylic acid and its esters continue to expand their production capacity. The current annual production capacity of acrylic acid in the world is about 2.6 million tons and 2.3 million tons of acrylate. The United States, Western Europe and Japan are the main producing areas. Abroad acrylates are mainly used for the production of surface coatings and adhesives. In addition to acrylic acid, acrylics are used in the production of superabsorbents, detergents and dispersants.
China produced acrylic acid and its ester products in the 1960s, but both used acrylonitrile hydrolysis and were small in scale. In 1984, Beijing Oriental Chemical Plant introduced Japanese technology to build an annual production capacity of 45,000 tons of acrylic devices. Since then, China's acrylic ester industry has made great progress. At present, the main domestic manufacturers include Beijing Dongfang Chemical Plant, Jilin Chemical Company, and Shanghai Gaoqiao Petrochemical Company. The production process adopts propylene two-step oxidation method. At present, the annual production capacity of acrylic acid in China is 150,000 tons, and the annual production capacity of acrylate is 150,000 tons.
China's acrylic acid and its esters are mainly used in chemical fiber, textile, paint, leather and adhesive fields. In 2000, the social demand reached 290,000 tons, and the gap was 60,000 tons. It is predicted that by 2005, the demand for acrylic acid and its ester products will be 380,000 tons, of which demand for chemical fiber will be 45,000 tons, 40,000 tons for textiles, 30,000 tons for leather, and 75,000 tons for coatings. With 90,000 tons and other 100,000 tons, it is difficult to meet domestic demand based on the current operating rate of the plant. The production of acrylic acid and its ester products in China started late, and the production capacity and output were relatively small. To this end, people in the industry believe that, according to the characteristics of the industry, through technological improvements, increase production capacity, improve product quality and expand the application areas, so that acrylic acid and its ester industries continue to progress.
Until the mid-1970s, acrylic acid was mainly used to produce acrylic esters in the industry, accounting for about 62% of total acrylic acid consumption. It was used in construction, papermaking, leather, textile, plastic processing, packaging materials, daily chemicals, and water. Processing, oil extraction, metallurgy and other fields. In addition, it occupies a very important position in the field of fine chemicals. Polypropylene and acrylic copolymers produced with acrylic acid have traditionally been used only as dispersants, flocculants and thickeners. In the late 1970s, there were two new markets for polypropylene and acrylic copolymers—high water-absorbent resins and detergents, which provided bright prospects for the expansion of acrylics and promoted the acrylic industry. Acrylic acid industry is still an emerging industry in China. Its product chain is a high-tech, high-value-added product with a promising market outlook.
At the end of the 1960s, there were various preparation methods for acrylic acid: cyanohydrin hydrolysis, acrylonitrile hydrolysis, Reppe, and propylene oxidation. After the 1980s, new and expanded installations used propylene two-step oxidation. In this method, propylene is oxidized to acrolein by air in the presence of a composite metal oxide catalyst, and further catalyzed oxidation to acrylic acid. The method for producing acrylic acid depends mainly on the catalyst. The catalysts produced by Nippon Shokubai Chemicals and Mitsubishi Petrochemical Co., Ltd. are widely used due to their high activity, long life, and high mechanical strength. At present, most of the catalysts used in industry are molybdenum-based multi-component catalysts, followed by cobalt, nickel, iron, vanadium, copper, magnesium and other metals. The promoters include iron, arsenic, antimony, etc. The acidic components are Thorium and boron.
In industrial production, acrylates are generally divided into light esters and heavy esters.
Typical light esters are methyl acrylate and ethyl acrylate and can be produced in the same production plant. The heavy esters, butyl acrylate and octyl acrylate, can also be produced in the same apparatus. At present, acrylic acid and alcohol are mostly used in the direct esterification process to produce acrylates. Among them, the production of lighter esters usually uses sulfuric acid or acidic ion exchange resins as esterification catalysts, and the catalysts for the production of heavy esters vary according to the production process and the type of product.
At present, the development trend of acrylic acid and its ester production technology mainly focuses on the improvement of the process and the research of the catalyst. In terms of acrylic acid purification, Japan's Mitsubishi Petrochemical Co., Ltd. has successfully developed a reaction gas absorption tower and a five-tower purification process; Nippon Shokubai Chemical Co., Ltd. has also made effective improvements to the original extractive distillation process; U.S. companies have always been acetic acid-formaldehyde gas phase condensation. Conducted research and made some progress. In addition, on the basis of the traditional Mo-V catalyst, Japan’s Mitsubishi Petrochemical Company has made significant improvements in terms of additives, carriers, and preparation processes, which have resulted in lower reaction temperatures, higher selectivity, and longer catalyst life. Mo-V-Zr composite catalyst was developed by So-hio of the United States for fixed-bed reaction. The yield of acrolein to produce acrylic acid can exceed 95%. Improvements in acrylate synthesis technology are also emerging. For example, the synthesis of butyl acrylate and 2-ethylhexyl ester has shifted to the continuous process.
In the 1990s, the production of acrylic acid and its esters culminated. With the development and popularization of acrylic superabsorbents and household washing aids, companies engaged in the production of acrylic acid and its esters continue to expand their production capacity. The current annual production capacity of acrylic acid in the world is about 2.6 million tons and 2.3 million tons of acrylate. The United States, Western Europe and Japan are the main producing areas. Abroad acrylates are mainly used for the production of surface coatings and adhesives. In addition to acrylic acid, acrylics are used in the production of superabsorbents, detergents and dispersants.
China produced acrylic acid and its ester products in the 1960s, but both used acrylonitrile hydrolysis and were small in scale. In 1984, Beijing Oriental Chemical Plant introduced Japanese technology to build an annual production capacity of 45,000 tons of acrylic devices. Since then, China's acrylic ester industry has made great progress. At present, the main domestic manufacturers include Beijing Dongfang Chemical Plant, Jilin Chemical Company, and Shanghai Gaoqiao Petrochemical Company. The production process adopts propylene two-step oxidation method. At present, the annual production capacity of acrylic acid in China is 150,000 tons, and the annual production capacity of acrylate is 150,000 tons.
China's acrylic acid and its esters are mainly used in chemical fiber, textile, paint, leather and adhesive fields. In 2000, the social demand reached 290,000 tons, and the gap was 60,000 tons. It is predicted that by 2005, the demand for acrylic acid and its ester products will be 380,000 tons, of which demand for chemical fiber will be 45,000 tons, 40,000 tons for textiles, 30,000 tons for leather, and 75,000 tons for coatings. With 90,000 tons and other 100,000 tons, it is difficult to meet domestic demand based on the current operating rate of the plant. The production of acrylic acid and its ester products in China started late, and the production capacity and output were relatively small. To this end, people in the industry believe that, according to the characteristics of the industry, through technological improvements, increase production capacity, improve product quality and expand the application areas, so that acrylic acid and its ester industries continue to progress.
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