Distillation, destructive fractional

Batch Distillation Evaporation and Condensation Continuous Distillation Fractionation Rectification Reflux Distillation Vacuum Distillation Steam Distillation Azeotropic Extractive Distillation Destructive Distillation Molecular Distillation Distillation by Compression and Sublimation)... 

See destructive distillation batch distillation extractive distillation rectification dephlegmation flash distillation continuous distillation simple distillation reflux fractional distillation azeotropic distillation vacuum distillation molecular distillation hydrodistillation. 

Historical. Pyridines were first isolated by destructive distillation of animal bones in the mid-nineteenth century (2). A more plentifiil source was found in coal tar, the condensate from coking ovens, which served the steel industry. Coal tar contains roughly 0.01% pyridine bases by weight. Although present in minute quantities, any basic organics can be easily extracted as an acid-soluble fraction in water and separated from the acid-insoluble tar. The acidic, aqueous phase can then be neutrali2ed with base to Hberate the pyridines, and distilled into separate compounds. Only a small percentage of worldwide production of pyridine bases can be accounted for by isolation from coal tar. Almost all pyridine bases are made by synthesis. 

There s a good reason why methanol is commonly called wood alcohol. The early commercial source was the destructive distillation of the fresh-cut lumber from hardwood trees. When wood is heated without access to air at temperatures above 500°F, it decomposes into charcoal and a volatile fraction. Among the compounds in the volatile fraction is methanol. Hence, the name wood alcohol or wood spirits. 

Shell Stills. At the beginning of the period under review, large quantities of crude oil were processed in tower stills. These were cylindrical vessels 10 to 15 feet in diameter and about 40 feet long. The vessels were mounted horizontally and arranged so that a fire could be applied to the underside (10, 55). The stills were charged with crude oil and the appropriate fractions removed by distillation. The residue was then destructively distilled or coked. Heating was continued until the bottom of the still was at a dull red heat (55). 

Pure 0-terphenyl can be obtained by fractional distillation. To obtain high purity m- or -terphenyl, the appropriate distillation fraction has to be further purified by recrystallizing, zone refining, or other refining techniques. Currently, little demand exists for pure isomers, and only a mixture is routinely produced. Small amounts of acetone, ethanol, or methanol are used to promote dehydrocondensation, and as a result, minor amounts of methyl- or methylene-substituted polyphenyls accompany the biphenyl and terphenyls produced. For most purposes, the level of such products (<1%) is so small that their presence can be ignored. For applications requiring removal of these alkyl-polyphenyl impurities, an efficient process for their oxidative destruction has been described (38). 

A model system demonstrating the nutritional destruction of lysine in bovine plasma albumin (BPA) by reaction with either a dialdehyde (MA) or a keto-aldehyde (MGA) was studied in relation to reaction rates as affected by pH, temperature, reaction time and carbonyl concentration. The BPA was Fraction V obtained from Schwartz/Mann and had a molecular weight of 69 x 103 with sixty lysine residules/mole, an assayed content of 11.4%. It was dissolved in 0.0200 M phosphate-citrate buffer adjusted to the desired pH. Malonaldehyde was prepared by acid hydrolysis of its bis-(dimethyl acetal). An aqueous solution of pyruvic aldehyde was diluted with distilled water and phosphate-citrate buffer to give an MGA solution of the desired pH (16). 

The proof for the formula XII is as follows. The full methylation of difructose anhydride III yielded a hexamethyl derivative, non-crystalline but readily distillable at 161-165° in a vacuum of 0.42 mm. The hydrolysis of hexamethyl-difructose anhydride III in 0.8 N aqueous hydrochloric acid at 95° appeared to reach half completion in about ninety-one minutes it is evident that the substance is rather difficult to hydrolyze. There i.s some destruction of the hydrolytic products in the acid solution with the formation of furfural derivatives, and it was found best to stop the hydrolysis at the half stage and separate the trimethyl-D-fructose fraction from the unhydrolyzed material by distillation in vacuo, the hydrolyzed products being more volatile the still residue was again hydrolyzed to the half stage and the separation repeated. In this manner there was obtained a yield of about 58% redistilled trimethyl-D-fructose, the specific rotation of which in chloroform is in the range = + 25-30°. Although this value is near that of pure 3,4,6-trimethyl-D-fructose, which is - - 26.6°, the agreement proved to be fortuitous because the sirup was not solely 3,4,6-trimethyl-D-fructose. It contained 3,4,6-trimethyl-D-fructose (readily identified by oxidation to... 

Wax Content. The Deutsche Industrie Normen (DIN) method utilizes destructive distillation of the asphalt, followed by freezing out of the wax in the distillate fractions. 

Although the liquid fraction was not collected in the experiments while feeding coal or sawdust, a liquid fraction and a char fraction were collected while pyrolyzing a municipal solid waste mixture. The liquid fraction represented 7.0% and the char fraction was 13.5% (moisture and ash-free weight basis) of the inlet solid feed. This contrasts with the data reported by Sanner et al. (9) who destructively distilled a municipal refuse in a retort constructed to simulate a coke oven process. They found that a 900 °C, the liquid fraction from the refuse was about 47% and the char fraction was close to 9%. The equipment used by Sanner and co-workers allowed the effluent gases to be cooled immedi-... 

PHYSICAL PROPERTIES mixture of coal tar, coal tar pitch, and creosote condensed coke oven emissions consist of a brownish, thick liquid or semisolid naphthalene-like odor is characteristic of condensed coke oven emissions uncondensed coke oven emissions contain vapors that escape when the ovens are changed and emptied contain chemicals such as benzo(a)pyrene, benzanthracene, chrysene, and phenanthrene OSHA defines coke oven emissions as the benzene-soluble fraction of total particulate matter present during destructive distillation or carbonization of coal to produce coke. 

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