1979-10-7
Acrylic acid
CAS: 79-10-7
Molecular Formula: C3H4O2
1979-10-7 - Names and Identifiers
1979-10-7 - Physico-chemical Properties
| Molecular Formula | C3H4O2 |
| Molar Mass | 72.06 |
| Density | 1.051 g/mL at 25 °C (lit.) |
| Melting Point | 13 °C (lit.) |
| Boling Point | 139 °C (lit.) |
| Flash Point | 130°F |
| Water Solubility | MISCIBLE |
| Solubility | 1000g/l |
| Vapor Presure | 4 mm Hg ( 20 °C) |
| Vapor Density | 2.5 (vs air) |
| Appearance | Liquid |
| Color | Clear |
| Odor | Acrid odor |
| Exposure Limit | TLV-TWA 10 ppm (30 mg/m3) (ACGIH). |
| Maximum wavelength(λmax) | ['231nm(lit.)'] |
| Merck | 14,130 |
| BRN | 635743 |
| pKa | 4.25(at 25℃) |
| PH | 3.68(1 mM solution);3.14(10 mM solution);2.63(100 mM solution); |
| Storage Condition | Store at +15°C to +25°C. |
| Stability | Stability Unstable - may contain p-methoxyphenol as an inhibitor. Prone to hazardous polymerization. Combustible. Incompatible with strong oxidizing agents, strong bases, amines. |
| Sensitive | Air Sensitive |
| Explosive Limit | 3.9-19.8%(V) |
| Refractive Index | n20/D 1.421 |
| Physical and Chemical Properties | Colorless liquid with pungent odor. Soluble in water, ethanol and ether. |
1979-10-7 - Risk and Safety
| Risk Codes | R10 - Flammable R20/21/22 - Harmful by inhalation, in contact with skin and if swallowed. R35 - Causes severe burns R50 - Very Toxic to aquatic organisms |
| Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S45 - In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. |
| UN IDs | UN 2218 8/PG 2 |
| WGK Germany | 1 |
| RTECS | AS4375000 |
| FLUKA BRAND F CODES | 8-13 |
| TSCA | Yes |
| HS Code | 29161110 |
| Hazard Class | 8 |
| Packing Group | II |
| Toxicity | LD50 orally in rats: 2.59 g/kg (Smyth) |
1979-10-7 - Reference Information
| pH indicator color change ph range | 1-2 |
| LogP | 0.46 at 25℃ |
| (IARC) carcinogen classification | 3 (Vol. 19, Sup 7, 71) 1999 |
| NIST chemical information | Information provided by: webbook.nist.gov (external link) |
| EPA chemical information | Information provided by: ofmpub.epa.gov (external link) |
| Overview | Acrylic acid is the simplest unsaturated carboxylic acid, and its molecular structure is composed of a vinyl group and a carboxyl group. Pure acrylic acid is a colorless and clear liquid with a pungent odor characteristic . Density 1.0511. Melting point 14 ℃. Boiling point 140.9 ℃. Strong acidity. It's corrosive. Soluble in water, ethanol and ether. Chemical properties are lively. Easy to polymerize into transparent white powder . Propionic acid is generated during reduction. 2-chloropropionic acid is generated when added with hydrochloric acid. It is used to prepare acrylic resins, etc., and also used in other organic synthesis. It is obtained by oxidation of acrolein or hydrolysis of acrylonitrile, and can also be synthesized by acetylene, carbon monoxide and water, or by pressure oxidation of ethylene and carbon monoxide. Acrylic acid can undergo the characteristic reaction of carboxylic acid, and the corresponding esters can also be obtained by reacting with alcohol. The most common acrylates include methyl acrylate, butyl acrylate, ethyl acrylate and 2-ethyl acrylate. After acrylic acid and its esters are mixed with other monomers, they will polymerize to form homopolymers or copolymers. Monomers that can usually be copolymerized with acrylic acid include amides, acrylonitrile, vinyl , styrene and butadiene. These polymers can be used to produce various types of plastics, coatings, adhesives, elastomers, floor polishes and coatings. |
| Discovery history | In 1843, it was first discovered that acrolein was oxidized to produce acrylic acid. In 1931, the American Roma-Haas Company successfully developed the cyanoethanol hydrolysis process to acrylic acid, which was the only production method in the industry for a long time. In 1939, the German W.J. Repe invented the carbonylation of acetylene to produce acrylic acid. In 1954, an industrial plant was established in the United States. At the same time, the process of acrylonitrile hydrolysis to acrylic acid was successfully developed. Since the United Carbide Company of the United States built an industrial plant for the production of acrylic acid by propylene oxidation in 1969, various countries have adopted this method for production. In recent years, propylene oxidation has made many improvements in catalyst and process, and has become the main method for producing acrylic acid. |
| Production method of acrylic acid | Acetylene carbonylation method Acetylene, carbon monoxide, water and solvent tetrahydrofuran, with nickel halide (see complexation catalyst) as catalyst, Copper halide is used as the co-catalyst, at 160~200 ℃, 4.0 ~ 5.5MPa, acrylic acid is obtained by carbonylation (see carbonyl synthesis): CH ≡ CH H2O CO ─→CH2 = CHCOOH This method is gradually being replaced by the propylene oxidation method. acrylonitrile hydrolysis acrylonitrile can obtain pure acrylic acid by secondary hydrolysis and distillation under reduced pressure in the presence of sulfuric acid: CH2 = CHCN H2O H2SO4-→ CH2 = CHCONH2 · H2SO4CH2 = CHCONH2 H2SO4 H2O-→ CH2 = CHCOOH NH4HSO4 In recent years, due to the rapid development of propylene ammonification oxidation process to acrylonitrile, cheap acrylonitrile has been provided for acrylic acid production. Acrylonitrile Hydrolysis Method Acrylonitrile In the presence of sulfuric acid, pure acrylic acid can be obtained by secondary hydrolysis and distillation under reduced pressure: CH2 = CHCN H2O H2SO4-→ CH2 = CHCONH2 · H2SO4CH2 = CHCONH2 H2SO4 H2O-→ CH2 = CHCOOH NH4HSO4 In recent years, due to the rapid development of propylene ammonification oxidation process to acrylonitrile, cheap acrylonitrile has been provided for acrylic acid production. The propylene oxidation method is carried out in two steps: the first step is to use molybdenum-bismuth or antimony catalyst to oxidize propylene to acrolein; The second step is to use molybdenum-vanadium-tungsten catalyst (see metal oxide catalyst) to oxidize acrolein to acrylic acid: CH2 = CHCH3 O2-→ CH2 = CHCHO H2OCH2 = CHCHO 2O2-→ CH2 = CHCOOH propylene, steam and preheated air are mixed into the first reactor (see the figure below), the reaction temperature is 320~340 ℃, the pressure is 270kPa, the reaction gas is directly sent to the second reactor without separation, the reaction temperature is 280~360 ℃, and the pressure is 200kPa. Both reactors use molten salt as a heating medium. The gas from the second reactor is absorbed by water to obtain 30% ~ 40% acrylic acid aqueous solution, and pure acrylic acid is refined with a total yield of 87%. The tail gas of the absorption tower is partially emptied and partially recycled. |
| Acrylic resin | Acrylic resin is a general term for resins formed by polymerization of acrylic acid and methacrylic acid or its derivatives such as esters, nitriles, and amides. It is a colorless transparent resin with a specific gravity between 1.17 and 1.20. It has high transparency, light transmittance of 92% ~ 98%, refractive index of 1.48~1.50, and its excellent optical properties, it is comparable to optical glass and can penetrate ultraviolet rays, so it is commonly called plexiglass, and has the characteristics of light resistance, aging resistance, and easy coloring, and can be used in various bright colors. Even when heated and bent at a temperature of 95 ℃ ~ 110 ℃, whitening and cracking will not occur. It is light and not easy to break, and can be used as a substitute for glass. The processing performance is good, and the formed product can still be bent, bonded and machined for secondary processing. Because of this good characteristic, the resin is often used in optical lenses, lenses, etc., such as Schmidt lenses and Fresnel lenses for televisions, windproof mirrors, art supplies and furniture. acrylic resin has solid, solution and dispersion, etc. Widely used as lighting materials, decorations, advertising nameplates, coatings, etc. It is more expensive and limits its wider application. If the polymerization is carried out by replacing the methyl group with a cyano group, it can become a transient adhesive, which is commonly used for bonding glass, metal, plastic, rubber, etc. |
| acrylic coating | acrylic coating mainly includes thermoplastic acrylic coating, thermosetting acrylic coating, high solid acrylic coating, acrylic latex coating and water diluted acrylic resin coating. (1) the main component of thermoplastic acrylic coating is polymethyl methacrylate, but the simple polymethyl methacrylate is too brittle, and the adhesion to the substrate is poor, and the solvent is not easy to perform, because of its high glass transition temperature. The solid content of solvent-based thermoplastic acrylic coatings is too low (volume concentration is about 12%), and the dosage has dropped sharply after entering the 2070s. Instead, thermosetting acrylic coatings have been developed, especially high-solid acrylic coatings. (2) thermosetting acrylic resin can increase the non-volatile content of the coating, and cross-linking occurs during the curing process after the coating is constructed. In addition to the high solid content of thermosetting acrylic coatings, it also has better gloss and appearance, better chemical resistance, solvent resistance and alkali resistance, heat resistance, etc., the disadvantage is that it cannot be stored for a long time. Thermosetting acrylic coatings use melamine-formaldehyde resin or polyisocyanate as crosslinking agent. (3) it is difficult to prepare acrylic resin for high solid coating. Generally, the volume solid content of high-solid polyester coatings can reach 65% ~ 70%. Polyester is easy to ensure that there are more than two hydroxyl groups on each molecule, but acrylic resin is difficult to reach more than two hydroxyl groups on each molecule. In order to solve this problem, one is to increase the amount of hydroxyethyl methacrylate (HEMA), such as increasing it to 15%; The second is to make the molecular weight distribution of the resin as narrow as possible and the distribution of polar groups as uniform as possible. The latter is very critical in high solid coatings. At present, the volume solid content of high solid acrylic resin coating can reach 54% ~ 56% (the weight solid content can reach 70% ~ 72%) under the spraying viscosity. (4) acrylate latex is the best and most important latex. Compared with polyvinyl acetate emulsion, acrylic emulsion improves the flexibility and adhesion of the coating, and the cost is moderate. In addition, its outdoor durability, including anti-ultraviolet degradation, has been significantly improved, so it has been applied in wall architectural coatings, scrubbing and decontamination floor varnish, and paint printing paste. (5) water-diluted acrylic resin is a thermosetting resin. water-soluble polymer is first prepared and cross-linked to form a tough water-resistant coating film during film formation. Water-diluted acrylic paint can be used for painting, immersion paint and other occasions, the most successful application is can wall paint. Another important application is electrophoretic paint. |
| thermosetting acrylic resin coating | this coating has been widely used in the field of metal coating since it was published by PPG company in 1956. Although the coating contains functional groups that can generate crosslinking reaction by heating, it also has self-crosslinking type, but most of them are crosslinked with other substances (such as amino resin, polyester resin, epoxy resin, isocyanate compound, etc.) And curing. The main functional groups in industry are hydroxymethylamine, carboxyl, hydroxyl, and epoxy. The resin coating is superior to amino acrylic resin coating in terms of hardness, pollution resistance, chemical resistance, weather resistance, color retention, and heat resistance. the film performance of thermosetting acrylic resin coating is different from the monomer type and monomer content of the resin skeleton structure, as well as the cross-linking curing form. The above chart shows the effect of monomer on the film performance of thermosetting acrylic resin coating. In Japan, heat-curing acrylic resin coatings were mostly used in metal processing such as automobile spraying, primary drying of secondary coating, primary drying of primary coating, etc. The coating has excellent weather resistance, pharmaceutical resistance, pollution resistance, impact resistance and flex resistance. In addition to spraying for automobiles, it is also widely used for spraying household appliances, colored galvanized iron sheets, metal furniture, and commonly used machinery. The curing conditions vary according to the matrix acrylic resin and crosslinking agent, and it takes about 20~30min at 140~180 ℃. Furthermore, if the functional group uses hydroxyl group, diisocyanic acid is used as the crosslinking agent; if the epoxy resin is used, secondary amines are used as the crosslinking agent, and the two can be cured at room temperature. |
| use | polymer is prepared by homopolymerization or copolymerization for coatings, adhesives, solid resins, molding compounds, etc acrylic acid and its series of products, mainly its esters, have developed rapidly in recent years. Such as ethylene, propylene, vinyl chloride, acrylonitrile, etc., developed into an important raw material for the polymer chemical industry. Acrylic acid and its esters, as monomers of polymer compounds, have produced more than one million t in the world, while the output of polymers and copolymers (mainly emulsion resins) made from them is nearly 5 million t. These resins are used in many departments such as coatings, plastics, textiles, leather, paper making, building materials, and packaging materials. Acrylic acid and its esters can be used for organic synthesis and polymer synthesis, and most of them are used for the latter, and more are copolymerized with other monomers, such as ethylene acetate, styrene, methyl methacrylate, etc., to produce various properties of synthetic resin esters, functional polymer materials and various additives. Main application areas:(1) The warp yarn slurry is prepared from acrylic acid, methyl acrylate, ethyl acrylate, acrylonitrile, ammonium polyacrylate and other raw materials, which is better than the capacity of polyvinyl alcohol slurry. Save starch. (2) The adhesive uses acrylic acid, methyl acrylate, ethyl acrylate, acrylic acid -2-ethylhexyl ester and other copolymer latex, which can be used as an adhesive for electrostatic flocking and flocking, with good firmness and feel. (3) The water thickener uses acrylic acid and ethyl acrylate copolymer to make high molecular weight powder. It can be used as a thickener for oil fields. Each ton of products can increase the production of 500t crude oil, which has a good effect on the oil production of old wells. (4) The coated paper coating agent uses acrylic acid, butyl acrylate, acrylic acid -2-ethylhexyl ester, styrene and other quaternary copolymer latex as the coated paper coating, the color is not yellowed, the printing performance is good, and the non-stick roller is better than styrene butadiene latex, which can save dry cool. (5) Polyacrylic acid salts can produce various polyacrylic acid salt products (such as ammonium salt, sodium salt, potassium salt, aluminum salt, nickel salt, etc.) using acrylic acid. Used as a coagulation agent, water treatment agent, dispersant, thickener, food preservative, acid and alkali resistant desiccant, softener and other polymer additives. A colorless unsaturated carboxylic acid. |
| production method | 1. cyanoethanol method this method uses chloroethanol and sodium cyanide as raw materials to react to generate cyanoethanol, which is hydrolyzed at 175 ℃ in the presence of sulfuric acid to generate acrylic acid: if the hydrolysis reaction is carried out in methanol, methyl acrylate is generated. 2. Acrylonitrile hydrolysis method Acrylonitrile is first hydrolyzed with sulfuric acid to generate acrylamide sulfate, then hydrolyzed to generate acrylic acid, and by-product ammonium bisulfate. This method has been greatly developed in the American Roma-Haas Company. 3. The high-pressure Leipe method will dissolve acetylene in tetrahydrofuran, and react with carbon monoxide and water in the presence of a catalyst composed of nickel bromide and copper bromide to prepare acrylic acid. The characteristic of this method is: using tetrahydrofuran as the solvent can reduce the risk of high-pressure treatment of acetylene; at the same time, the catalyst does not use the nickel carbonyl used in the original Repez method, only nickel salt. Propylene is mixed with air and water vapor in a certain molar ratio. In the presence of molybdenum-bismuth and other composite catalysts, the reaction temperature is 310-470 ℃, and the acrolein is oxidized at normal pressure to obtain acrolein with a yield of 90%. Then acrolein is mixed with air and water vapor according to a certain molar ratio. In the presence of molybdenum-vanadium and other composite catalysts, the reaction temperature is 300-470 ℃, and the normal pressure oxidation produces acrylic acid with a yield of 98%. This method is divided into one step and two steps. The one-step method is that propylene is oxidized in one reactor to produce acrylic acid; the two-step method is that propylene is first oxidized in the first reactor to produce acrolein, and then acrolein enters the second reactor to oxidize to produce acrylic acid. According to the reactor structure, the two-step method is divided into fixed bed method and fluidized bed method. Among the industrial production methods of acrylic acid, the cyanoethanol method and the high-pressure Rape method have been basically eliminated. The previous use of acetic acid as a raw material was cracked into ketene, and then reacted with anhydrous formaldehyde to form propiolactone, and then contacted with hot phosphoric acid. Isomerized into acrylic acid. The ketene method or the β-propiolactone method is basically eliminated, and the acrylonitrile method is only used in a few old devices. At present, the industry mainly uses the improved Rape method and propylene oxidation method, and the latter is more common and the most promising. In the patent report, there is also a production method of propionic acid as a raw material. |
| category | flammable liquid |
| toxicity classification | moderate toxicity |
| acute toxicity | oral administration-rat LD50: 33.5 mg/kg; Oral administration-mouse LD50: 2400 mg/kg (reference: acrylic acid) |
| stimulation data | skin-rabbit 500 mg severe; Eye-rabbit 1 mg severe (reference: acrylic acid) |
| Explosive hazard characteristics | It can be exploded when mixed with air; it is easy to polymerize and heat in the container to cause explosion |
| flammability hazard characteristics | flammable, heated decomposition stimulating gas |
| storage and transportation characteristics | warehouse ventilation and low temperature drying; separate from oxidant storage and transportation |
| fire extinguishing agent | mist water, carbon dioxide, foam, dry powder |
| occupational standard | TLV-TWA 6 mg/m3; TWA 30 mg/m3 |
| auto-ignition temperature | 744 °F |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
Last Update：2024-04-10 22:41:03
