diketene
diketene
CAS: 674-82-8
Molecular Formula: C4H4O2
diketene - Names and Identifiers
diketene - Physico-chemical Properties
| Molecular Formula | C4H4O2 |
| Molar Mass | 84.07 |
| Density | 1.09g/mLat 25°C(lit.) |
| Melting Point | -7.5°C |
| Boling Point | 69-70°C100mm Hg(lit.) |
| Flash Point | 95°F |
| Vapor Presure | 7.9 mm Hg ( 20 °C) |
| Vapor Density | 2.9 (vs air) |
| Storage Condition | 2-8°C |
| Refractive Index | n20/D 1.439(lit.) |
| Physical and Chemical Properties | Characteristic colorless flammable liquid with irritating odor. melting point -6.5 ℃ boiling point 127.4 ℃ relative density 1.0897 refractive index 1.4379 flash point 33.9 ℃ solubility in water and common organic solvents. |
| Use | Used as dye, pigment, pesticide, pharmaceutical and organic synthesis intermediates |
diketene - Risk and Safety
| Hazard Symbols | Xn - Harmful |
| Risk Codes | R10 - Flammable R20 - Harmful by inhalation R40 - Limited evidence of a carcinogenic effect R36/37/38 - Irritating to eyes, respiratory system and skin. |
| Safety Description | S3 - Keep in a cool place. S36/37 - Wear suitable protective clothing and gloves. S33 - Take precautionary measures against static discharges. S24/25 - Avoid contact with skin and eyes. S23 - Do not breathe vapour. S16 - Keep away from sources of ignition. S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. |
| UN IDs | UN 2929 6.1/PG 2 |
| WGK Germany | 2 |
| RTECS | RQ8225000 |
| FLUKA BRAND F CODES | 19-21-27 |
| Hazard Class | 6.1(a) |
| Packing Group | I |
diketene - Upstream Downstream Industry
diketene - Nature
Open Data Verified Data
A colorless flammable liquid having an irritating odor. The relative density was 1. 0897. Melting Point -6.5 °c. Boiling point 127.4 °c. The refractive index (n ~ o) was 1. 4379, and the specific heat capacity was 0. 1990kj/(kg · c). Flash point 33.9 °c. Insoluble in water, soluble in common organic solvents. The chemical properties are active.
Last Update：2024-01-02 23:10:35
diketene - Preparation Method
Open Data Verified Data
acetic acid was cleaved at 750-780 °c in the presence of triethyl phosphate to give ketene. Further, polymerization was carried out at 8 to 10 ° C. To form diketene.
Last Update：2022-01-01 10:17:04
diketene - Use
Open Data Verified Data
mainly used as raw materials for organic synthesis, such as the synthesis of butanoic acid, acetoacetic acid esters, amides and Pyrazolones. It is also used in the manufacture of plasticizers, dyes, synthetic fibers, cellulose ester tablets, as well as pharmaceuticals (antipyretic and stabilizer), pesticides and food preservatives. In addition, in spices, food (sweeteners), feed additives (olaquindox) and synthetic resin, rubber, additives, there are also widely used.
Last Update：2022-01-01 10:17:05
diketene - Safety
Open Data Verified Data
- has a strong stimulating effect on the tissue mucosa, with a tear, poisoning in severe cases can cause emphysema, pulmonary edema, and even pulmonary hemorrhage and death. Animal MLC: Cat 1. O-1. 5rng/L, rabbit 2.5rng/L, rat 3.Orng/L. The maximum allowable concentration in air is 0.5-1.0 mg/m3. The operator should wear protective gear. Application of a large number of water on the skin, severe cases of extended treatment.
- This product is flammable and should be stored in aluminum or glass-lined containers at low temperature (0~5 ℃). No contact with fire, inorganic acid and water during transportation. No impact is allowed to prevent explosion. According to the provisions of flammable chemicals storage and transportation.
Last Update：2022-01-01 10:17:05
diketene - Reference Information
| NIST chemical information | information provided by: webbook.nist.gov (external link) |
| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| Overview | Diketene, also known as acetyl ketene or vinyl acetolactone, colorless or light yellow and irritating odor of flammable liquid, neither soluble in water nor water absorption, soluble in most organic solvents, long-time easy to polymerize. In addition, diketene flammable, explosive, its vapor has a tear, can make people poisoning. Because of its molecular structure contains two double bonds, it has a high degree of unsaturation, chemical properties are very active. It can react with alcohols, amines, halogens, aldehydes, ketones, acids, etc. by addition, decomposition, nitration, polymerization and the like to generate a variety of fine chemical intermediates. Therefore, it has a wide range of applications in medicine, pesticides, dyes, feed additives, organic synthesis and so on. |
| preparation method | According to the different raw materials of ketene synthesis can be divided into acetic acid pyrolysis method, acetylene oxidation method, pyrolysis of acetone and pyrolysis of acetic anhydride. 1. Acetic acid high temperature cracking method Ketene is prepared by thermal cracking and dehydration of acetic acid vapor at about 750 ℃ and 12 kPa with triethyl phosphate as catalyst, and then diketene is polymerized, see equations (1) and (2). FIG. 1 is the reaction formula for synthesis of diketene by high temperature pyrolysis of acetic acid 2. Acetylene oxidation when acetylene and oxygen are mixed in a molar ratio of 2 to 1 at 98 ℃ to 107 ℃, in the silica gel as the carrier of ZnO/CoO/Ag2O catalyst to stay for 1 s, can directly produce ketene, further polymerization to produce diketene, see the reaction formula (3) and (4). FIG. 2 is the reaction formula for synthesis of diketene by acetylene oxidation 3. acetone pyrolysis at high temperature (about 800 deg C) to obtain ketene, further polymerization to produce diketene, see reaction formula (5) and (6). FIG. 3 is the reaction formula of synthesizing diketene by acetone pyrolysis In this method, the purity of diketene gas is low due to the production of by-product methane, and it is difficult to eliminate residual acetone, it is therefore suitable for small-scale production. 4. Pyrolysis of acetic anhydride at 280 ℃ ~ 650 ℃, acetic anhydride is pyrolyzed to produce ketene, and further polymerized to produce diketene, see reaction equations (7) and (8). Figure 4 is the reaction formula |
| Application | 1. In the pharmaceutical industry, diketene reacts with an equivalent amount of chlorine gas to form 2, 4-dichloroacetoacetate chloride and then decarbonates to produce 1, 3-dichloroacetone, further, a 4-chloromethylthiazole compound was obtained by cyclization reaction using a sulfurized amide. This product is an intermediate of the anti-ulcer drugs methanesulfonthiazole and yizatidine. Epizole, prepared from diketene, is a pyrazolone antipyretic analgesic with little side effect on gastrointestinal tract and good analgesic effect. Its analgesic effect is about 3 times that of aminopyrine, in addition to its antiviral effect. 6-methyluracil, prepared by the reaction of diketene with urea in the presence of acetic anhydride, is an important intermediate for the synthesis of dipyridamole orotate, a vasodilator, and Rodenticide, and regulate the role of plant growth. The 4-chloroacetoacetate obtained by the reaction of diketene with chlorine is an intermediate for the synthesis of the side chain of the antibiotic cephalosporin. The α-acetylbutyrolactone prepared with ethylene oxide can be used as a starting material for vb1. Ethyl acetoacetate prepared by the action of anhydrous ethanol, can be used for the synthesis of anti-allergic drugs, cough medicine, cough ketone, central stimulant Tere alkali hydrochloride, anticoagulant new anticoagulant, A variety of pharmaceutical intermediates, such as vasodilator hexanone Cok base, diclofenac sodium, amoxicillin and so on. Agriculture In agriculture, diketene reacts with isobutyramide, isobutyronitrile, isobutyrate, etc. to produce 2-isopropyl-4-methyl-6-hydroxypyrimidine. The compound is reacted with ethyl chloride to obtain the organophosphorus insecticide diazinon, which can be used for corn, vegetables, fruit trees, rice and other crops. Permethrin prepared by the reaction of diketene with alcohols is an important intermediate for the production of pyrethroid insecticides, from which a series of insecticides such as permethrin, cypermethrin and cyfluthrin can be synthesized. The acetoacetyl diethylamine obtained by the reaction of diketene with diethylamine is an intermediate of phosphorus phosphorus insecticide; The acetoacetyl methylamine obtained by the reaction with monomethylamine is an intermediate of monocrotophos; the acetoacetyldimethylamine obtained by the reaction with dimethylamine is an intermediate of benzaphos. Diketene reacts with aldehydes to form 4-substituted Acetyl acetate, which is then cyclized under alkaline conditions to form 6-substituted 4-hydroxy-5, 6-dihydro-2-pyrone, it can be used for the synthesis of post-emergence herbicides with significant effects. The urea pyrimidine obtained by the reaction of diketene with dicyclopropylamine and the like is a pre-emergence herbicide that is non-destructive to crops such as cotton. Feed additive olaquindox (also known as keueling), prepared from diketene, ethanolamine and O-nitroaniline, is a promising feed additive. It can promote the growth of livestock and poultry, improve the feed conversion rate, shorten the feeding cycle and increase the proportion of lean meat of pigs by resisting Gram-positive and negative bacteria and assimilating protein, it has been widely used abroad. Synthesis of amino acids A variety of amino acids can be synthesized from diketene. Amino acids can be obtained by first ammoniating diketene to give butanone amide, then alkylating, and then treating with bromine in potassium hydroxide solution at low temperature. Different amino acids can be prepared separately using different alkylating agents. Such as leucine, isoleucine, phenylalanine, etc. Diketene and nitrite (Or acetic acid) with nitrous acid treatment, can be obtained α-oxime ethyl acetoacetate, with palladium catalytic hydrogenation reduction of oxime, and then platinum catalyst reduction of β-carbonyl, can be mixed threonine. 5. Dye Industry acetoacetanilide prepared by the reaction of diketene with aniline at 0- 15 ℃ can be used in the manufacture of pyrazolone, acid complex yellow GR, neutral deep yellow GL, neutral orange RL, light-resistant yellow G and other dyes. Acetoacetyl o-toluidine, prepared by reaction with o-toluidine at 10- 15 ° C., is useful as an intermediate for benzidine yellow pigment. The acetoacetyl-p-toluidine prepared by reaction with P-toluidine at 10- 15 ° C. Can be used as an intermediate of the bisazo pigment Hansa yellow. O-chloroacetoacetanilide obtained by condensation with O-chloroaniline in ethanol medium can be used to produce pigment yellow 10g, GP, neutral brilliant yellow 3GL, neutral dark brown BRL, neutral orange RL, etc. The acetoacetyl M-dimethylaniline obtained by the reaction with M-dimethylaniline can be used as an intermediate of biphenylamine yellow, wuerkang solid yellow GR, G. The acetoacetyl-2, 5-dimethoxyaniline obtained by the reaction with 2, 5-dimethoxyaniline is useful as an intermediate of an azo dye, Hansa Huang. O-acetoacetamidoanisole prepared by reaction with O-methoxyaniline can be used for the production of yellow light-resistant dye, direct light-resistant yellow 5G, etc. 6. Food Industry diketene in the presence of caustic, alkali metal salts of acids, tertiary amines and other catalysts, dehydroacetic acid and its sodium salt obtained by dimerization in toluene or benzene solution are important food additives. Can be used for cheese butter, margarine, cool drinks, fermented milk, lactic acid bacteria beverage, soybean milk and other additives. Organic synthesis A series of pyrazolone compounds can be obtained by condensation of acetoacetamide with arylhydrazine, which is obtained by the reaction of diketene with ammonia. For example, 1-phenyl-3-methyl-5-pyrazolone, 1-(4-chlorophenyl)-3-methyl-5-pyrazolone, and the like. They are important intermediates in the synthesis of pharmaceuticals and dyes. Can be used for the production of antipyretic and analgesic drugs such as antipyrine, analgin, etc.; For the production of silk, wool fabric special dyes permanent yellow G, neutral orange RL, neutral pink BL, etc. Diketene and chlorine at low temperature prepared α-Chloroacetyl acetyl chloride is the intermediate of red pigment quinrone; In medicine can be synthesized cephalosporin derivatives; Can also be used in the synthesis of pesticides. Acetoacetanilide products produced by condensation of diketene with various aromatic amines can be processed into a variety of organic pigments and dyes such as acid complex yellow GR, biphenylamine yellow, permanent Yellow 2G, strong yellow R, etc; it can also be used as a colorant for plastics, rubber, etc. Such as acetyl acetanilide, O (p)-Chloroacetyl acetanilide, O-methyl (OXY) acetyl acetanilide, 2, 4-dimethyl acetyl acetanilide, etc. Acetoacetate ester products prepared by the reaction of diketene with alcohols are important raw materials for organic synthesis. For example, methyl Acetyl acetate, ethyl ester, isopropyl Ester, allyl Ester and the like can be used as pesticides, dyes, pigments, solvents, chelating agents, polymerization catalysts, pharmaceutical raw materials and the like. Polymer Industry diketene can undergo acetyl acetylation with many polymers, thereby improving its physical properties and expanding its use. Such as diketene used in paper coating, can improve the waterproof and fireproof properties of paper. The composite resin obtained by the interaction of diketene with polyvinyl alcohol and vanadium bisulfate can be used as a catalyst in the reaction of preparing caprolactam from cyclohexanone. The wood coating curing agent prepared from diketene has excellent heat and water resistance. The nylon 6 is treated with diketene and chelated with calcium, zinc, cobalt or aluminum compounds to give fibers with good antistatic properties. 9. Other The condensation of diketene with 1, 4-butanediol can give 1, 4-butanediol bis-β-aminocrotonate, and the reaction with isobutyronitrile can give the rubber antioxidant butene carboxylic acid lactone. In addition, diketene can also be used for the preparation of non-toxic stabilizers of polyethylene; For the synthesis of a wide range of heterocyclic compounds. Such as pyrrole derivatives, isoxazole derivatives, pyrazolone derivatives, pyrimidine derivatives, thiazole derivatives and quinoline derivatives. |
| Main references | [1] raw materials for the synthesis of dyes, pigments, pharmaceuticals, etc. In addition, it is also widely used in pesticides, fungicides, plasticizers, fiber modifiers, etc. [2] Sun Yuquan et al. Synthesis and application of diketene. Shanxi chemical. 2007.27(1):47-49. [3] Jindong et al. Production and application of diketene. Sichuan chemical industry and corrosion control. 2001.4(3):35-38. |
| Use | as an organic synthesis reagent, used in the preparation of pesticides, dyes, pigment intermediates =, acetoacetanilide (AAA) and pyrazolone (PMP) derivatives. used as dye, pigment, pesticide, medicine and organic synthesis intermediate diketene is an important intermediate of pesticide and medicine, which can be used to prepare bactericide seed dressing, limingamine, benomill, dimetriol, dipyrimidine, insecticide monocrotophos, phosphonium, muscarinic phosphorus, ameriocamba, pyrimidine oxyphosphorus, bendazapril, diazinonidine, verapamil, dimethoate, herbicide alachlor, acetochlor, butachlor, quetiapine, toxachlor, salbutamol, etc. The reaction ability of diketene is very strong, can be derived from a variety of products, is a fine chemical dyes, pharmaceuticals, pesticides, food and feed additives, additives and other raw materials. The acetoacetyl diethylamine obtained by the reaction of diketene and diethylamine is an intermediate of The organophosphorus insecticide phosphoramidite, while the acetoacetyl methylamine obtained by the reaction with monomethylamine is an intermediate of monocrotophos. Diketene reacts with ammonia to form acetoacetamide, which is used to synthesize dye intermediate 1-(4-chlorophenyl)-3-methyl-5-pyrazolone, 1-(4-sulfonylphenyl)-3-methyl-5-pyrazolone; Diketene reacts with ethanol to form ethyl acetoacetate, which is used in the synthesis of dye intermediates 1-phenyl-3-methyl-5-pyrazolone, 1-(2, 5-dichloro-4-sulfonylphenyl)-3-methyl-5-pyrazolone and the like. From these intermediates can be prepared dye permanent yellow G, acid medium jujube BN, neutral orange RL, neutral brown 5RL, neutral dark brown BRL, acid yellow G, weak acid yellow G, acid yellow 2G, active yellow K-6G, active yellow M-5G, active bright yellow X-6G, neutral pink BL, etc. 1-phenyl -3-methyl -5-pyrazolone and its derivatives are more used in the production of antipyretic analgesics antipyrine, aminopyrine, analgin and so on. Diketene may also be used in the synthesis of amino acids. Diketene and O-nitroaniline, ethanolamine as raw material, can be prepared feed additive olaquindox (fast-growing spirit). Diketene is used to synthesize various heterocyclic compounds, such as pyrrole derivatives, isoxazole derivatives, pyrazolone derivatives, pyrimidine derivatives, thiazole derivatives, Quinoline compounds, coumarin compounds and furan derivatives; Diketene can also be reacted with a series of compounds to produce pyrone, pyridone, dioxane, oxazine and flavonoid compounds. |
| production method | industrial acetic acid to prepare diketene, can also be used acetone, acetic anhydride, acetic acid ester as raw materials for thermal decomposition. Acetone thermal decomposition method can be used for small-scale production, this method because of methane production, the purity of the obtained ketene gas is low, and the removal of residual acetone is also more difficult. Glacial acetic acid in the presence of triethyl phosphate is cleaved at 750-780 °c to give ketene, which is then polymerized at 8-10 °c to give diketene. The preparation method is that acetic acid is thermally cracked at about 700 ° C. In the presence of triethyl phosphate as a catalyst to dehydrate to produce ketene, and the purified ketene gas is dimerized to form diketene in an absorption tower. If the temperature is too high, the produced diketene will be highly polymerized to form polyvinylketone, and ammonia gas as a polymerization inhibitor must be added during the thermal cracking of acetic acid to avoid decomposition of the ketene. The process is that acetic acid is gasified by a gasifier (at about 40 kPa), triethyl phosphate of 0.3% of the charged amount of acetic acid is added to the acetic acid vapor, and then heated to the reaction temperature by a preheater, quickly through the cracking tube, and the polymerization inhibitor ammonia is added, the reactant is condensed and fractionated, and the unreacted acetic acid is fractionated, the ketene mixed gas in the condenser generates diketene (absorbed by diketene) in a diketene absorption tower, and then undergoes thin film distillation to obtain a finished product. The reaction equation is as follows: CH3COOH [triethyl phosphate] →[750~780 ℃]CH2CO H2O |
| category | toxic substances |
| toxicity grade | poisoning |
| Acute toxicity | oral-rat LD50: 560 microliters/kg; Oral-mouse LDL0: 800 mg/kg |
| stimulation data | Skin-rabbits 20 mg/24 h moderate; eye-rabbit 0.05 mg/24 h severe |
| flammability hazard characteristics | open flame, high thermal flammability; Function with oxidant; combustion releases stimulus smoke |
| storage and transportation characteristics | The warehouse is ventilated and dried at low temperature; With oxidant (ammonium nitrate), separate storage of food additives |
| extinguishing agent | water, foam, sand. |
| Occupational Standard | sel 1 mg/m3 |
| toxic substance data | information provided by: pubchem.ncbi.nlm.nih.gov (external link) |
| immediate life-and health-threatening concentration | 7.6 ppm |
Last Update：2024-04-09 02:00:10
Supplier List
Spot supply
Product Name: diketene Request for quotationCAS: 674-82-8
Tel: +86-17551318830
Email: r@reformchem.com
Mobile: +86-17551318830
QQ: 3785839865
Spot supply
Product Name: *Acetyl Ketene Visit Supplier Webpage Request for quotationCAS: 674-82-8
Tel: 0714-3999186
Email: 2853786052@qq.com
Mobile: 86+15671228036
QQ: 2853786052
Wechat: 15671228036
Product Name: diketene Request for quotation
CAS: 674-82-8
Tel: 17505222756
Email: pules.cn@gmail.com
Mobile: +86-17551318830
Wechat: 17505222756
CAS: 674-82-8
Tel: 17505222756
Email: pules.cn@gmail.com
Mobile: +86-17551318830
Wechat: 17505222756
Product Name: diketene Request for quotation
CAS: 674-82-8
Tel: 0086-551-65418684
Email: sales@tnjchem.com
info@tnjchem.com
Mobile: 0086 189 4982 3763
QQ: 2881500840
Wechat: 0086 189 4982 3763
WhatsApp: 0086 189 4982 3763
Product List: View Catalog
CAS: 674-82-8
Tel: 0086-551-65418684
Email: sales@tnjchem.com
info@tnjchem.com
Mobile: 0086 189 4982 3763
QQ: 2881500840
Wechat: 0086 189 4982 3763
WhatsApp: 0086 189 4982 3763
Product List: View Catalog
Spot supply
Product Name: diketene Request for quotationCAS: 674-82-8
Tel: +86-17551318830
Email: r@reformchem.com
Mobile: +86-17551318830
QQ: 3785839865
Spot supply
Product Name: *Acetyl Ketene Visit Supplier Webpage Request for quotationCAS: 674-82-8
Tel: 0714-3999186
Email: 2853786052@qq.com
Mobile: 86+15671228036
QQ: 2853786052
Wechat: 15671228036
Product Name: diketene Request for quotation
CAS: 674-82-8
Tel: 17505222756
Email: pules.cn@gmail.com
Mobile: +86-17551318830
Wechat: 17505222756
CAS: 674-82-8
Tel: 17505222756
Email: pules.cn@gmail.com
Mobile: +86-17551318830
Wechat: 17505222756
Product Name: diketene Request for quotation
CAS: 674-82-8
Tel: 0086-551-65418684
Email: sales@tnjchem.com
info@tnjchem.com
Mobile: 0086 189 4982 3763
QQ: 2881500840
Wechat: 0086 189 4982 3763
WhatsApp: 0086 189 4982 3763
Product List: View Catalog
CAS: 674-82-8
Tel: 0086-551-65418684
Email: sales@tnjchem.com
info@tnjchem.com
Mobile: 0086 189 4982 3763
QQ: 2881500840
Wechat: 0086 189 4982 3763
WhatsApp: 0086 189 4982 3763
Product List: View Catalog
View History
Raw Materials for diketene
Downstream Products for diketene
Butanoic acid, 3-oxo-, 2-methylpropyl ester
2'-Chloroacetoacetanilide
N-Methyl acetoacetylamide
Acetoacetanilide
2'-Chloroacetoacetanilide
N-Methyl acetoacetylamide
Acetoacetanilide