1.Overview
2-methylimidazole(CAS.NO:693-98-1) pesticide production antitrichomonal Flagyl (metronidazole) intermediates. Is epoxy resin curing agent , and other curing accelerator , an amine curing agent occupies a special position in the epoxy resin curing agent in the temperature ,which may be used alone , in a short time after heat treatment , heating can be obtained cured high temperature deformation . It is mainly used for powder molding and powder coating curing accelerator .
2.Uses
1)for pharmaceutical intermediates metronidazole , is epoxy resin curing agent , and other.
2)This product is a medication metronidazole and feed growth promoters dimethyl azole intermediates, as well epoxy and other resin curing agent. As the temperature of the solid epoxy resin through the agent may be used alone , but primarily for powder molding and powder coating curing accelerator .
3.Preparation
1)glyoxal , acetaldehyde , and ammonia as raw materials , the reaction of 2-methyl-imidazole crude, sublimation purification , can be obtained products.
2)ethylenediamine and acetonitrile as raw materials , the reaction in the presence of sulfur to produce imidazoline , again in the presence of a nickel catalyst , at 200 ℃ dehydrogenation , can be prepared from 2 - methylimidazole products.
3)to glyoxal and methylamine in the presence of formaldehyde reaction , can be obtained.
4.Production methods
From 2-methylimidazoline eliminate dehydrogenation . 2-imidazoline heating and melting (melting point 107 ℃), active nickel was added carefully , the reaction temperature was raised to 200-210 ℃ 2h. Cooling to below 150 ℃ , dissolved in water , hot pressure filtration , separation active nickel , the filtrate was concentrated to a temperature above 140 ℃ , discharge cooling that is to give 2 - methylimidazole. With the production of a purity of ≥ 98% of the product , 1t products consume ethylene diamine (95%) 1095kg, acetonitrile 975kg. A better approach is to use glyoxal and formaldehyde as raw materials .
5. 2-methylimidazole and environment
2-Methylimidazole's production and use in the manufacture of pharmaceuticals, photographic and photothermographic chemicals, dyes, pigments, agricultural chemicals and rubber may result in its release to the environment through various waste streams. If released to air, an estimated vapor pressure of 6.9X10-4 mm Hg at 25 deg C indicates 2-methylimidazole will exist solely as a vapor in the atmosphere. Vapor-phase 2-methylimidazole will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 4.1 hours. 2-Methylimidazole does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, 2-methylimidazole is expected to have very high mobility based upon an estimated Koc of 33. The pKa of 2-methylimidazole is 7.86, indicating that this compound will partially exist in cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces may be an important fate process based upon an estimated Henry's Law constant of 4.1X10-6 atm-cu m/mole. However, volatilization from moist soil may be attenuated because the compound exists partially as a cation and cations do not volatilize. Utilizing the Japanese MITI test, 1% of the Theoretical BOD was reached in four weeks indicating that biodegradation is not an important environmental fate process. If released into water, 2-methylimidazole is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces may be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 190 hours and 62 days, respectively. An estimated BCF of 3.2 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to 2-methylimidazole may occur through inhalation and dermal contact with this compound at workplaces where 2-methylimidazole is produced or used. The general population may have limited exposure to this compound from consumer products containing 2-methylimidazole.
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