Bromine Oxide The Oxidation Of Ethyl Bromide

Ethane is the second content of the natural gas,which has never been used sufficiently for the using and the conversion of the natural gas,especially has never been used as an industry material for the production of higher valuable products in industy and pharmacy.Higher hydrocarbons is used as clean fuel which is refined from oil purifying.The major process for the conversion of natural gas to liquid fuels is initial from syngas,which is called Fischer-Tropsch process.But this is an energy consuming process.More than one fourth of natural gas must be burned to generate heat for the steam reforming of the other raw material.Based on the utilization of the natural gas,a technics for the synthesization of higher hydrocarbons with ethane through non-synthesis gas process was designed,which include two steps:in the first step,the ethane was converted to ethyl bromide by the bromination of ethane,and in the second step,ethyl bromide became higher hydrocarbons through the dehydrogen bromide reaction of ethyl bromide.By this method,ethane could be high efficiently converted to higher hydrocarbons.In the process, a little or hardly any carbon dioxide was produced.And the research work of this paper is mostly focused on the research of the synthesization of ethyl bromide.In the ethane oxidative bromination reaction,ethyl bromide was synthesized on the catalyst with nitrogen as internal standard and ethane, oxygen,hydrogen bromide(40wt%in water)as raw material,and the reaction is strong exothermic reaction.The different catalysts were filtrated firstly,and the reaction conditions such as reaction temperature, hydrogen bromide fluent,the flux ratio of ethane to oxygen and gas space velocity were systematicly researched for the effect of ethane conversion, ethyl bromide selectivity,and the selectivity of carbon monoxide and carbon dioxide.The characteristic of the catalysts was also discussed on the results of BET and XRD characterization for the research of the connection between the structure and the surface of the catalysts and the catalytical capability of the catalysts.The result of the catalysts filtration showed that the catalyst 6.0%Fe4.0%K1.0%La/SiO₂ has the better catalytical effect.On the conditions that the fluent of hydrogen bromide is 4.0ml/h,the fluent of nitrogen,ethane and oxygen were 5.0,20.0,5.0ml/min,respectively,the reaction temperature is 380℃,the conversion of ethane was 30.9%,the selectivity of ethyl bromide was 84.3%,and the total selectivity of CH₃Br,C₂H₃Br,C₂H₂Br₂ and C₂H₄Br₂ is 7.7%.The life-span experiment results showed that the conversion of ethane was still above 30%,the ethyl bromide selectivity was above 80%,and the selectivities of deep oxidation production of carbon monoxide and carbon dioxide were below 10%after 13 hours reaction.The characterization of BET and XRD results showed that the catalytical action of the catalyst with iron as the active component was improved with auxiliary agent of potassium added in,the stability of the catalyst was highly improved with lanthanon lanthanum added.And the BET characteristic results also showed that 800 degrees of the catalysts baking temperature had lesser specific surface area,the small specific surface area is propitious to decrease the deep oxidation and to increase the ethyl bromide selectivity.In this paper,we also discussed the mechanism of oxidative bromination of ethane.The result showed that it was a radical reaction, under the reaction condition of 380℃,the oxidation of ethyl bromide and slight steaming reforming of ethyl bromide occurred.And CO was the primary source of the ethyl bromide burning reaction.However,we still do not know in detail.The research work is still in progress in this aspect.