| Methyl ethyl ketone(MEK),also known as butanone,as a ketone compound,has a very wide range of applications in industry,and is often used in intermediates of chemical raw materials and industrial organic solvents.There are many methods for producing methyl ethyl ketone,but most of the raw materials are derived from non-renewable petroleum resources.Therefore,it is particularly important to explore a non-petroleum-based raw material for the efficient production of methyl ethyl ketone.This thesis is devoted to the production of methyl ethyl ketone through the catalytic dehydration of 1,3-propanediol,which is a by-product from the microbial synthesis of 2,3-butanediol,and With H3PO4 as the active component,three kinds of solid acid catalysts are prepared with different carriers by the impregnation and subsequent calcination process.The technology developed can not only avoid the waste of limited petroleum-based raw materials,but can also solve the problems of high cost,large energy consumption and serious pollution,which is in line with the concept of green environmental protection and sustainable development.The specific research contents are as follows:1.Preparation and performance investigation of H3PO4/SiO2 catalyst.The catalyst is prepared by the equal volume impregnation method,and the regular influence between the catalyst preparation process conditions and reaction conditions and the catalytic activity and methyl ethyl ketone selectivity is explored.Studies have shown that the SiO2 carrier has no catalytic activity in the dehydration of 2,3-butanediol,and the addition of the active component of H3PO4 can induce the catalytic dehydration of 2,3-butanediol,and has a great influence on the catalytic performance The amount can make 2,3-butanediol nearly complete reaction.The 10 wt%H3PO4/SiO2 catalyst calcined at 450? temperature can make 2,3-butanediol completely converted under the optimal reaction conditions,and the yield of methyl ethyl ketone is 84.13%.2.Preparation and performance investigation of H3PO4/CaX catalyst.The catalyst is prepared by the equal volume impregnation method,and various characterization techniques are used to explore the rules between different preparation process conditions and catalyst structure and catalytic performance.The results show that the active component is highly dispersed in the carrier and does not destroy the original structural characteristics of the carrier zeolite CaX;when the loading of H3PO4 is 8 wt.%,the H3PO4/CaX catalyst prepared by roasting at 500? has catalytic the optimal activity.At the same time,the effects of reaction temperature and mass space velocity on the catalytic activity and selectivity are explored.The results of the study found that:the optimal reaction process conditions,at this time 2,3-butanediol can achieve a conversion rate of 98.87%,the yield of methyl ethyl ketone is 85.72%.3.Preparation and performance investigation of H3PO4/AC catalyst.In order to further improve the performance of the catalyst,activated carbon(AC)with larger surface area and richer pore structure is selected as the carrier to prepare H3PO4/AC catalyst.Under the optimal preparation process conditions and the optimal reaction conditions,2,3-butanediol has been completely converted,and the yield of methyl ethyl ketone is the largest(91.27%).Various characterization methods are used to explore the structural characteristics and loading of H3PO4/AC catalyst.And examined the existence form of the active component of the catalyst,It is found that after the catalyst is calcined,the active component could form an interaction with the carrier,and mainly existed in the form of phosphoric acid and metaphosphoric acid.,Accompanied by the presence of a small amount of P2O5.The experiment also studied the service life of the H3PO4/AC catalyst in the reaction of 2,3-butanediol dehydration to methyl ethyl ketone,and regenerated the H3PO4/AC catalyst by regeneration means to investigate the catalytic performance of the regenerated H3PO4/AC catalyst.The experimental results show that the catalyst still maintains a high conversion rate of 2,3-butanediol(92.05%)and methyl ethyl ketone selectivity(69.78%)after 140 h of use.And the H3PO4/AC catalyst used 6 times can also have good catalytic activity.The catalysts prepared by different support materials are compared,and the relationship between the specific surface and pore structure of different supports and the catalytic activity is investigated,as well as the relationship between the acid strength and the catalytic activity of different catalysts.The experiment found that the H3PO4/AC catalyst has the best catalytic activity,because the large specific surface is easier to adsorb active components,thereby forming more active centers,and the reaction speed is accelerated.It has suitable acid strength and is more suitable for inducing 2,3-butanediol catalytic dehydration to prepare methyl ethyl ketone. |
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