State one difference between the following
A. CO and Co
B. Cl and Cl1-
C. Acidic and basic radical
D. Oxidising and reducing agent
E. Catalyst and promoter
Answers
Explanation:
Introduction
The reduction of organochlorine compounds is essential to the organic synthesis and, for example, is applied for aldehydes synthesis from carboxylic acid chlorides or for obtaining by this method compounds containing a lower number of chlorine atoms compared to the initial ones.
Of great importance is knowledge of the C–Cl bonds behavior under reduction conditions of other functional groups in the same molecule. The reduction of C–Cl bond to C–H bond is also used to prove the structure and analysis of organochlorine compounds [1].
In principle, any C–Cl bond can be converted to a C–H bond; however, the reduction ease and selectivity strongly depend on the structure of the chlorine-containing functional group on presence and location of other functional groups in the molecule, and on the nature of the reducing agent. So, for example, chlorine bound to a vinyl carbon atom is usually replaced with harder hydrogen, and that to an allyl easier than in saturated chlorohydrocarbons. The accumulation of chlorine atoms or other electron-withdrawing groups on a carbon atom bound to chlorine facilitates the reduction. A chlorine atom located in the alpha position to the electron-withdrawing group is replaced more easily than more distant chlorine atoms in the same molecule.
The reactivity series of organochlorine compounds in the reducing reactions can, however, vary significantly depending on the reduction mechanism. So, for example, in heterolytic reduction, primary chlorine derivatives are more reactive than secondary ones, and in homolytic reduction the ratio is opposite [1].
Various methods for C–Cl bonds reduction in non-cyclic organochlorine compounds can be divided into the following groups:
Electrochemical reduction.
Radiolysis of organochlorine compounds.
Hydrogenation with hydrogen—thermal and catalytic.
Reduction with metal hydrides and complex hydrides of elements.
Metal reduction in the presence of hydrogen donors.
Reduction with metal salts of lower valency.
Of these methods, the catalytic reduction with hydrogen and reduction with complex hydrides of elements are the most widely used and studied [1,2,3].
Hydrodechlorination processes also have a pronounced applied value. Hydrodechlorination end products are hydrocarbons and HCl.
In general, the reaction can be written as
R1R2HmCln + ℓH2 → R1R2H(m+2ℓ-n) + nHCl
Given the fact that hydrodechlorination makes it possible quantitatively remove chlorine with the formation of environmentally sound hydrocarbons, one can explain the growing interest in these processes from the point of view of their perspective as methods for industrial wastes processing at the most chemical industries [4,5,6,7]. The data in Figure 1 indicate the growth of publications on hydrodechlorination problems in the last few decades.
Catalysts 10 00216 g001 550
Answer:
A. Carbon monoxide is a molecule, cobalt is an element
B. chlorine atom (Exists as Cl2) and chloride ion. size of Cl1- is greater than Cl
C. Positive charged radicals are called negative radicals and negatively charged radicals are called positive radicals.
D. Oxidising agent oxidises the reactant and gets reduced. In simple terms, OA gains e- and gets reduced while RA loses e- and gets oxidised.
E. Catalyst can alter the rate of reaction but promotors increase the efficiency of catalyst.