Selective phenol methylation to 2,6-dimethylphenol in a fluidized bed of iron-chromium mixed oxide catalyst with o-cresol circulation

Abstract

Background2,6-dimethylphenol (2,6-DMP) is a product of phenol methylation, especially important for the plastics industry. The process of phenol methylation in the gas phase is strongly exothermic. In order to ensure good temperature equalization in the catalyst bed, the process was carried out using a catalyst in the form of a fluidized bed - in particular, the commercial iron-chromium catalyst TZC-3/1.ResultsSynthesis of 2,6-dimethylphenol from phenol and methanol in fluidized bed of iron-chromium catalyst was carried out and the fluidization of the catalyst was examined. Stable state of fluidized bed of iron-chromium catalyst was achieved. The measured velocities allowed to determine the minimum flow of reactants, ensuring introduction of the catalyst bed in the reactor into the state of fluidization. Due to a high content of o-cresol in products of 2,6-dimethylphenol synthesis, circulation in the technological node was proposed. A series of syntheses with variable amount of o-cresol in the feedstock allowed to determine the parameters of stationary states.ConclusionA stable work of technological node with o-cresol circulation is possible in the temperature range of350-380°C, and o-cresolin/phenolin molar ratio of more than 0.48. Synthesis of 2,6-DMP over the iron-chromium catalyst is characterized by more than 90% degree of phenol conversion. Moreover, the O-alkylation did not occur (which was confirmed by GC-MS analysis). By applying o-cresol circulation in the 2,6-DMP process, selectivity of more than 85% degree of 2,6-DMP was achieved. The participation levels of by-products: 2,4-DMP and 2,4,6-TMP were low. In the optimal conditions based on the highest yield of 2,6-DMP achieved in the technological node applying o-cresol circulation, there are 2%mol. of 2,4-DMP and 6%mol. of 2,4,6-TMP in the final mixture, whereas 2,4,6-TMP can be useful as a chain stopper and polymer’s molar mass regulator during the polymerization of 2,6-DMP.

Upgrading oxygenated Fischer-Tropsch derivatives and one-step direct synthesis of ethyl acetate from ethanol - examples of the desirability of research on simple chemical compounds transformations

“…This secondary reaction is not always intentional [ 129 ]. During the alkylation of phenol [ 130 ] with alcohols higher than methanol the competitive reaction can occur: bimolecular condensation of primary alcohols to ketones containing 2n-1 carbon atoms [ 124 ],[ 131 ],[ 132 ]. Ketonization of primary alcohols, and consequently aldehydes and esters, allows the synthesis of symmetrical and unsymmetrical ketones [ 133 ],[ 134 ] and expands possibilities of utilization of such materials [ 134 ],[ 135 ].…”

In Vitro and In Vivo Metabolic Activation and Hepatotoxicity of Environmental Pollutant 2,6-Dimethylphenol

“…They can be extracted or produced from many industrial products . 2,6-DMP is used in the synthesis of polyphenylene oxide, which is extensively employed in commercial manufacturing, and is an important intermediate in the synthesis of drug mexiletine as well. , However, the serious environmental pollution problems caused by the mass production and application of 2,6-DMP not only endanger aquatic organisms but may even affect others on the earth . 2,6-DMP can be detected in contaminated groundwater at 41 μg/L. , In addition, as a priority contaminant in coal gasification wastewater, 2,6-DMP can be found at about 100 mg/L .…”

Experimental and Predicted Vapor–Liquid Equilibrium for Diisopropanolamine with m-Cresol and 2,6-Dimethylphenol at 20.0 kPa

“…m -Cresol (MC) and 2,6-dimethylphenol (DMP) are of great importance for the basic organic chemical industry. MC is mainly employed to synthesize spices, cosmetics, and pharmaceutical products et al Furthermore, DMP can be employed to synthesize engineering plastic polyphenylene oxide (PPO), 2,6-diphenylamine, antiarrhythmic drugs, etc. , MC and DMP are presenting in coal tar and products of chemical synthesis. MC and DMP should be separated and purified because of their wide applications.…”