Ethyl formate purification

Cyclohexene, purification of, 41, 74 reaction with zinc-copper couple and methylene iodide, 41, 73 2-CyclohEXENONE, 40,14 Cydohexylamine, reaction with ethyl formate, 41, 14... 

Ethyl formate, condensation with 2-methylcydohexanone, 48, 41 purification of, 48, 42 Ethyl isocyanate, reaction with N,N-dimethy 1-1,3-propanediamine,... 

The submitters used ethyl formate, 97%, available from Janssen Chimica, without further purification. Dimethylformamide (DMF) can be used instead of ethyl formate with the same operating conditions. The checkers used ethyl formate (99%), available from Aldrich Chemical Company, Inc., without further purification. 

A stirred suspension of Z-Alap (5.2 g, 20 mmol) and HC(OEt)3 (25 g, 170 mmol) was slowly heated. The ethyl formate and EtOH byproducts were continuously removed by distillation while allowing the temperature to rise to 135 °C where it was held for 1 h. The cooled mixture was filtered. The excess HC(OEt)3 was removed from the filtrate under a high vacuum leaving Z-Alap(OEt)2 as a viscous gum used in the next step without purification yield 6g (95%). 

Chromium trioxide, 21, 6 24, 39, 76 Cinnamic acid, 20, 77 22, 26 24, 21 Cinnamoyl chloride, 20, 77 24, 21 Citral, bisulfite compound, 23, 78 purification of, 23, 78 Claisen condensation, with acetone and ethyl formate, 27, 92 with ethyl oxalate and ethyl succinate, 26,42... 

Racemic 2-aminobutan-l-ol (1) is a cheap chemical which can be easily resolved into both its enantiomers on an industrial scale. The asymmetric synthesis of chiral amines from hydrazines derived from (7 )-(—)-2-aminobutan-l-ol [(R)-(—)-l], using the general strategy disclosed in early works, is summarized here. The title hydrazine (4) is prepared as follows (eq 1). Treatment of the amino alcohol [(7 )-(—)-l] with excess ethyl formate followed by LAH reduction of the intermediate formamide gives the N-methylamine [(7 )-(—)-2]. IV-Nitrosation of the latter afforded (R)-(+)-3 which is next reduced to the hydrazine [( )-(—)-4] by means of LAH. Being unstable, the hydrazine (4) must be used immediately without purification. 

Aminoisoxazole hydrochloride (1.33 g, 11 mmol) is refluxed (24 h) in a mixnire of formic acid (11ml) and ethyl formate (110 ml). After concentration of the mixture in vacuo the resulting oil is diluted with toluene and re-evaporated to give a dark tan solid. Flash chromatography [34] (MeOH-CHCl3, 5 95) gives the product (1.09g, 89%), m.p. 125-129°C. Further purification can be achieved by recrystallization from cyclohexane-ethyl acetate. 

Pentanone and ethyl formate were purchased from Aldrich Chemical Company, Inc. and used without further purification. 

Chlorinated by-products of ethylene oxychlorination typically include 1,1,2-trichloroethane chloral [75-87-6] (trichloroacetaldehyde) trichloroethylene [7901-6]-, 1,1-dichloroethane cis- and /n j -l,2-dichloroethylenes [156-59-2 and 156-60-5]-, 1,1-dichloroethylene [75-35-4] (vinyhdene chloride) 2-chloroethanol [107-07-3]-, ethyl chloride vinyl chloride mono-, di-, tri-, and tetrachloromethanes (methyl chloride [74-87-3], methylene chloride [75-09-2], chloroform, and carbon tetrachloride [56-23-5])-, and higher boiling compounds. The production of these compounds should be minimized to lower raw material costs, lessen the task of EDC purification, prevent fouling in the pyrolysis reactor, and minimize by-product handling and disposal. Of particular concern is chloral, because it polymerizes in the presence of strong acids. Chloral must be removed to prevent the formation of soflds which can foul and clog operating lines and controls (78). 

By-products from EDC pyrolysis typically include acetjiene, ethylene, methyl chloride, ethyl chloride, 1,3-butadiene, vinylacetylene, benzene, chloroprene, vinyUdene chloride, 1,1-dichloroethane, chloroform, carbon tetrachloride, 1,1,1-trichloroethane [71-55-6] and other chlorinated hydrocarbons (78). Most of these impurities remain with the unconverted EDC, and are subsequendy removed in EDC purification as light and heavy ends. The lightest compounds, ethylene and acetylene, are taken off with the HCl and end up in the oxychlorination reactor feed. The acetylene can be selectively hydrogenated to ethylene. The compounds that have boiling points near that of vinyl chloride, ie, methyl chloride and 1,3-butadiene, will codistiU with the vinyl chloride product. Chlorine or carbon tetrachloride addition to the pyrolysis reactor feed has been used to suppress methyl chloride formation, whereas 1,3-butadiene, which interferes with PVC polymerization, can be removed by treatment with chlorine or HCl, or by selective hydrogenation. 

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