| Name | ketene |
| Synonyms | Keten ketene ethenone carbometene Ethen-1-one Carbomethene |
| CAS | 463-51-4 |
| EINECS | 207-336-9 |
| Molecular Formula | C2H2O |
| Molar Mass | 42.04 |
| Density | 0.6600 |
| Melting Point | -150° |
| Boling Point | bp -56° |
| Appearance | Morphological Gas |
| Refractive Index | 1.3040 (estimate) |
| Physical and Chemical Properties | Chemical properties colorless gas. Melting point -151 ℃, boiling point -56 ℃. Soluble in water, slightly soluble in ether, aromatic hydrocarbons, halogenated hydrocarbons, ketones and esters. It is extremely unstable and must be stored at a low temperature of -80°C. It is polymerized into diketene at room temperature. The diketene is heated and decomposed to produce ketene, which is similar to acetic anhydride or chlorine. |
| Use | Uses Ketene is very active, mainly used in the manufacture of acetic anhydride and as acetylation reagent. Reaction with ethanol to generate ethyl acetoacetate; Reaction with bromine to generate bromoacetyl bromide; Reaction with water, ethanol, acetic acid and metal organic compounds to generate acetic acid, ethyl acetate, acetic anhydride and ketone, respectively. Ketene is a raw material for a variety of industrial organic chemicals. |
| UN IDs | 1955 |
| Hazard Class | 2.3 |
| Raw Materials | methylketene Phenoxatellurin |
| Downstream Products | 2,2,6-Trimethyl-4H-1,3-dioxin-4-one Dichloroacetyl chloride |
production method
There are two kinds of industrial methods. 1. Acetic acid pyrolysis acetic acid vapor is obtained by pyrolysis dehydration with triethyl phosphate as catalyst at about 700 ℃ and under slight pressure. 95%(W/V) acetic acid liquid is metered by a flowmeter and added to a gasifier for gasification. The gasifier is mixed with 10% triethyl phosphate aqueous solution and enters a tubular reactor made of high chromium steel. The temperature is controlled at 700±20 ℃ for cracking. The cracking gas is mixed with ammonia gas (stabilizer) and enters the three-stage condenser of the 1. 2. respectively. The second stage of the 1. condenses and separates dilute acetic acid with a content of about 40%, which is concentrated and recycled. The third stage is condensed and separated to obtain about 70% acetic anhydride. The yield of the cooled cracked gas ketene can reach 90% based on acetic acid. 2. Acetone pyrolysis method introduces acetone vapor into a tube with a temperature of 650-800 ℃. In addition to ketene, the pyrolysis gas also contains acetone, methane, ethylene and carbon monoxide. The finished product is obtained by staged cooling and condensation purification. In addition, acetylene and oxygen are mixed in a molar ratio of 2:1, and ketene can be directly generated by staying on ZnO/CaO/Ag2O catalyst supported by silica gel at a temperature of 98-107 ℃ for 1s.
category
Harmful gases
toxicity classification
High toxicity
acute toxicity
inhalation-mouse LC50: 17 PPM/ 10 points
explosive hazard characteristics
Steam and air can be exploded when mixed
flammability hazard characteristics
Flammable; fire scene releases spicy and irritating smoke
storage and transportation features
The warehouse is ventilated and dry at low temperature; stored and transported separately from the oxidant
fire extinguishing agent
Dry powder, carbon dioxide, foam
occupational standards
TWA 0.9 mg/m3; STEL 3 mg/m3
| toxic substance data | 463-51-4(Hazardous Substances Data) |
| immediate threat to life and health concentration | 5 ppm |
| exposure limit | TLV-TWA 0.9 mg/m3 (0.5 ppm); STEL 3.0 mg/m3 (1.5 ppm) (ACGIH); IDLH 50 ppm (NIOSH). |
| EPA chemical information | Ketene (463-51-4) |