ketene synthesis

8synthesis methods

Product Name:ketene
CAS Number:463-51-4
Molecular formula:C2H2O
Molecular Weight:42.04

Ketene may be prepared also by pyrolysis of acetic anhydride or phenyl acetate or diketene. Other sources are quite unsatisfactory from a standpoint of yield. Small quantities may be made conveniently by heating acetone in a “ketene lamp.” This is a glass apparatus containing a Nichrome filament, heated electrically to red heat. Larger amounts are made by passing acetone or acetic acid through a tube at 700 °C. A very brief contact time is required, so that much of the acetone is undecomposed and has to be condensed and recycled. Also, it is imperative that the reaction tube be of inert material such as porcelain, glass, quartz, copper or stainless steel. A copper tube, if used, should be protected from oxidation by an iron sheath. Inert packing may be used (glass, vanadium pentoxide, porcelain), but just as good yields are obtained with empty tubes. No catalyst is known which accelerates this decomposition at significantly lower temperatures.

64-17-5 Synthesis

64-17-5
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463-51-4
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75-07-0 Synthesis

75-07-0
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$14.00/5mL

64-19-7 Synthesis

64-19-7
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$10.00/25ML

141-78-6 Synthesis

141-78-6
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Yield:-

Reaction Conditions:

with oxygen at -133.16; under 4E-10 Torr;

Steps:

For the reaction studies, the pre-conditioned npAu catalyst was exposed to molecular oxygen at 300 K by backfilling the vacuum chamber via a leak valve, and all exposures reported here are in units of Langmuir (1L = 10-6 Torr s). The relative oxygen coverage (in percent of the saturation coverage) was determined by comparison with the oxygen saturation calibration curve (see below). Ethanol and 1-butanol were introduced to the catalyst surface at the temperatures specified (typically below 180 K) by monitoring the ambient pressure in the chamber. Surface concentrations of O_ads used were relatively low (10 % of saturation) in order to minimize over oxidation of the alcohols. It is not possible to determine the absolute coverage of Oads on npAu becausethe active surface area was not known. A typical experiment consisted of oxygen exposure to the catalyst surface at 300 K followed by cooling of the sample to180-140 K before dosing the alcohol. A trace amount ofwater condensed on the surface during cooling (less than1 % of the amount observed in a typical alcohol oxidationreaction). The catalyst was then heated, and the reactionmonitored by temperature programmed reaction spectroscopy (TPRS) according to well-established protocols. The heating rate for all temperature programmed reactions was nearly constant at *3 ± 0.5 K s-1. The reaction products were identified by quantitative mass spectrometry (Hiden HAL/3F) using fragmentation patterns obtained from authentic samples (see Supporting Information).

References:

Stowers, Kara J.;Madix, Robert J.;Biener, Monika M.;Biener, Juergen;Friend, Cynthia M. [Catalysis Letters,2015,vol. 145,# 6,p. 1217 - 1223]

FullText

22118-09-8 Synthesis