Formation of hydantoins in gasifier condensate water. [5,5-dimethyl hydantoin synthesis by reaction of acetone cyanohydrin with excess ammonium carbonate]
A number of 5,5-diakyl and 5-alkylhydantoins have been detected in the condensate water from the gasification of Indian Head (ND) lignite in the University of North Dakota Energy Research Center (UNDERC) slagging fixed bed gasifier. These compounds do not form directly in the gasifier. They were shown to be either absent or present in low concentrations in water samples which were collected from a side stream sampler on the UNDERC gasifier and quickly frozen. When this side stream condensed water was heated in a constant temperature bath at 40/sup 0/C, hydantoin concentrations increased in an approximately second-order manner. The formation is believed to proceed by the Bucherer-Berg reaction, the same reaction used in commercial hydantoin synthesis, from ammonia, carbonate, hydrogen cyanide and various ketones and aldehydes at a pH of 8.5. A kinetic study was undertaken to obtain useful rate data for this reaction. Reliable and reproducible concentration data for acetone and cyanide were impossible to obtain for the raw gasifier condensate water because of the presence of reversible addition products of cyanide such as acetone cyanohydrin and 2-amino-2-methylpropanonitrile as well as large amounts of sulfide. Thus a model system was investigated where acetone cyanohydrin was reacted with excess ammonium carbonate at concentrations approaching those obtained in the condensate water, 0.020M and 0.25M, respectively. The reaction was studied at 50/sup 0/, 70/sup 0/, and 90/sup 0/C using a capillary GC (0V351 phase) for the analysis of 5.5-dimethylhydantoin (DMH) using 4-methoxyphenol as the internal standard. Results are discussed. 8 references, 2 tables.
- Research Organization:
- North Dakota Univ., Grand Forks (USA). Energy Research Center
- DOE Contract Number:
- FC21-83FE60181
- OSTI ID:
- 6083345
- Report Number(s):
- DOE/FE/60181-77; CONF-850417-9; ON: DE85004658
- Country of Publication:
- United States
- Language:
- English
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AMMONIUM CARBONATES
AMMONIUM COMPOUNDS
CARBON COMPOUNDS
CARBONATES
CHEMICAL ANALYSIS
CHEMICAL REACTION KINETICS
CHROMATOGRAPHY
COAL GASIFICATION PLANTS
GAS CHROMATOGRAPHY
HYDROGEN COMPOUNDS
INDUSTRIAL PLANTS
KINETICS
LIQUID WASTES
MEDIUM TEMPERATURE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PH VALUE
REACTION KINETICS
SEPARATION PROCESSES
SYNTHESIS
TEMPERATURE DEPENDENCE
WASTE WATER
WASTES
WATER