The Control Over Chemical Reactions

2875 WordsNov 25, 201412 Pages
The control over chemical reactions is of greatest interest since early times. The four basic well known variables that are capable of controlling chemical reactions are temperature, pressure, concentration and contact time.1 Therefore in 19th and early 20th century’s high temperatures and pressures were employed in order to achieve reasonable production rates in most industrial reaction processes. Unfortunately these harsh conditions were associated with several disadvantages and problems. Because they are energy intensive, corrosive or otherwise damaging to equipment and materials and nonselective-results leading to undesirable side reactions and side products.1 Sudden breakthrough occurred with emergence of catalysis which is a phenomenon where chemical reactions are accelerated by small quantities of extraneous substances referred to as catalysts.2 The term catalysis was first proposed by Jons Jakob Berzelius1, 2 in 1835comes from the Greek words kata meaning down and lyein meaning loosen. However some of the catalytic reactions such as production of alcohol from sugar by fermentation is known and practiced long before. Besides Berzelius, many others also devoted their work for catalysis in different aspects. Fundamental work carried out by Ostwald 2was recognized with the Nobel Prize for chemistry in 1909 where he defined catalysis as acceleration of chemical reactions by the presence of foreign substances which are not consumed. Basically catalytic reactions are
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