The Role Catalysts In Chemical Reactions, Their Importance In Industry

The Role Catalysts In Chemical Reactions, Their Importance In Industry, Problemsand New DevelopmentsOXFORD AND CAMBRIDGE SCHOOLS EXAMINATION BOARD. General Certificate examen- Advanced Level Chemistry (Salters) - Paper 3 mock.ROBERT TAYLOR U6JW.A Catalyst is a substance that alters the rate of a reaction. The catalystremains unchanged at the end of the reaction. The process is called contact action.In this report I aim going to explain the role of catalysts in chemicalreactions and their importance in industry. I lead also outline the problemsassociated with the use of some catalysts and discuss, using appropriateexamples, new-sprung(prenominal) developments in this area which will help reduce damage to theenvironment.The process of catalysis is essential to the modern day manufacturing industry.Ninety per cent, over a trillion dollars worth, of manufactured items areproduced with the help of catalysts every year. It is therefore logical thatscientists are evermore searching f or new improved catalysts which willimprove efficiency or produce a greater yield.An blisteryic catalyst works due its acid nature. Catalysts are strongacids and readily give up hydrogen ions, or protons H+. Protons can be releasedfrom hydrated ions, for example H3O+, but more commonly they are released fromionisable hydroxyl groups (R-OH) where the O-H bond is broken to produce R-O-and H+. When the reactant receives protons from an acid it undergoes aconformational change, (change in shape and configuration), and becomes areactive intermediate. The intermediate can indeed either become an isomer byreturning a proton to the catalyst, or it may undergo a further reaction andform a completely new molecule.Up until the mid - 1960s silica-alumina gels were used to catalyse the crackingof hydrocarbons. This form of cracking is where the large molecules in oil areconverted into small, highly volatile molecules. further because the size of thepores of silica-alumina gels was so variabl e, (ranging from 0.1nm to 50nm), andthe fact that their shape was so variable, they were hardly ideal catalysts. Dueto the large size of their cavities, large carbonaceous products were able toform in the cavities thus lowering the re body process if the catalyst. Catalysiswith alumina silica-gels was also difficult to control precisely because oftheir indefinite structure, and therefore uneven d... ...ce onthe surface of the unfaltering therefore the solvent only acts as a form of heattransfer and a working fluid.In summary I see support reagents as the best possible solution to theproblems associated with catalysis due to their easy use and their ability to berecovered and re-used. They have a high take of activity and improvedselectivity in reactions. This is accompanied by their highly catalytic activitywhich leads to the best possible level of performance in commercial uses. Thishas already been proven by the use of active reagents in Friedel - Craftsreactions. These reactio ns originally had the drawbacks of firstly thehydrolysed aluminium chloride containing aqueous effluent which is produced, andsecondly the by-products such as polymeric tars and di- and polysubstituted by-products which are produced which unless they can be successfully removed makethe product impure. By using a supported reagent catalyst, in most cases thedesired level of activity can be achieved but the catalyst can be removed easilyfrom the reaction mixture and re-used. I personally therefore feel that the futurity of environmentally friendly catalysis lies with supported reagentcatalysts.