Acetylene liquefied gases

Butadiene is available commercially as a liquefied gas underpressure. The polymerization grade has a minimum purity of 99%, with acetylene as an impurity in the parts-per-million (ppm) range. Isobutene, 1-butene, butane and cis-l- and Zrc//7.s-2-butcnc have been detected in pure-grade butadiene (Miller, 1978). Typical specifications for butadiene are purity, > 99.5% inhibitor (/c/V-butylcatecliol). 50-150 ppm impurities (ppm max.) 1,2-butadiene, 20 propadiene, 10 total acetylenes, 20 dimers, 500 isoprene, 10 other C5 compounds, 500 sulfur, 5 peroxides (as H2O2), 5 ammonia, 5 water, 300 carbonyls, 10 nonvolatile residues, 0.05 wt% max. and oxygen in the gas phase, 0.10 vol% max. (Sun Wristers, 1992). Butadiene has been stabilized with hydroquinone, catechol and aliphatic mercaptans (lARC, 1986, 1992). 

SULFUROUS OXIDE (7446-09-5) SO, Noncombustible liquefied gas under pressure or liquid. Contact with air forms hydrogen chloride fumes. Violent reaction with water or steam, forming sulfurous acid, a medium-strong acid and corrosion hazard. Reacts violently with acetylene, acrolein, alcohols, aluminum powder alkali metals (i.e., potassium, sodium) amines, ammonia, bromine pentafluoride butadiene caustics, cesium acetylene carbide chlorates, chlorine trifluoride chromium powder copper or copper alloy powders chlorine, diethylzinc, fluorine, ethylene oxide lead dioxide lithium acetylene carbide diamino-, metal powders monolithium acetylide-ammonia nitryl chloride potassium acetylene carbide potassium acetylide, potassium chlorate rubidium carbide silver azide sodium acetylide staimous oxide. Decon oses in... 

Acetylene can only be stored in a gaseous state. The supply as liquefied gas, as with air gases (argon, nitrogen, oxygen and the like), is ruled out due to the very high risk of explosion. 

Chemical Designations - Synonyms Allene-methylacetylene mixture MAPP gas Methylacetylene-allene mixture Propadiene-methylacetylene mixture Chemical Formula. CH3C=CH+CH2=C=CHj Ohservahle Characteristics - Physical State (as shipped) Liquefied compressed gas Color. Colorless Odor Offensive, like acetylene. 

In the 1940 s, in addition to these operations, two other processes became important. Acetic acid was made by reacting methanol with carbon monoxide, and acetic anhydride was being made by the ethylidene diacetate process, which in effect is the dehydration of acetic acid to the anhydride by the use of acetylene. Fermentation ethyl alcohol was converted to acetic acid via acetaldehyde as well as by the direct oxidation of ethyl alcohol. A new operation on the Gulf Coast was also based on acetaldehyde. However, the acetaldehyde is made by the direct oxidation of liquefied petroleum gas. A further process for the production of these materials, in which acetaldehyde is oxidized in one step to a mixture of anhydride and acid, was also begun. 

Cooking constitutes a source of VOCs in the indoor environment Food stuffs and fuels emit ample amounts of VOCs. For example, up to 54 hydrocarbons were identified from a study of 16 fuels/ stoves combinations that are usually used in urban and rural settings in China (Tsai et al., 2003). The worst stove/fuel VOC emitters include metal stoves with a flue/unprocessed coal powder, metal stoves with a flue/washed coal powder, brick stove with a flue/maize residue while the least emitters ofVOCs are traditional gas stove/coal gas fuel, improved brick stove with a flue/maize residue and metal coal stove with a flue/honeycomb coal briquette. Many of the compounds emitted in substantial amounts are reactive unsaturated compounds such as benzene, ethylene, acetylene, and propene. For example, up to 2856 mg of ethylene was emitted by per kg of coal powder in the metal stove. Similarly, the observation of elevated levels of benzene and toluene in a food-court in South China has been rationalized in terms of emission from liquefied petrol gas (LPG) stoves (Tang et al., 2005). Thus, cooking is an important contributor of precursors of photochemical smog. 

Acetylene (C2H2) is a colorless and flammable gas. At 100 percent purity, acetylene is odorless, but at commercial purity it has a garliclike odor. Acetylene can be liquefied and solidified with ease, although in both cases it explodes with extreme violence when ignited. 

Ethylene has so far appeared to be a much less expensive raw material than acetylene. It is likely to remain so for some time, even if the price of crude oil rises, if, simultaneously, reservoir chemistry based on liquefied petroleum gas, and ethane in particular, develops at the expected rate. This means that the most widespread methods will continue to rely on chlorination or bxychlorination of ethylene, either alone or, more generally, combined in integrated schemes, each one followed by the cracking of the ethylene dichloride produced. 

Gases - flammable gases include LPG (liquefied petroleum gas in cylinders, usually butane or propane), acetylene (used for welding) and hydrogen. An explosion can occur if the air/ gas mixture is within the explosive range. 

TB-I5 Tare Weights, Requirements for Marking Cylinders (Post Manufacture). Defines terminology, requirements, and procedures for marking tare weights on cylinders of 1000 lbs. or less water capacity to be filled with liquefied compressed gas (except acetylene). (3 pages)... 

Fuel Gases—gases intended for burning in air or oxygen. Examples are acetylene, butane, hydrogen, liquefied petroleum gas (LPG), methyl acetylene-allene mixture (MAPP gas), propane, and other hydrocarbons. 

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