Determination of Carbonyl Compounds with Ammonium Hexanitratocerate (IV) Reagent in Nitric Acid Medium at Micro Scale

INTRODUCTION

The compounds containing carbonyl group may be either aldehydic or ketonic and both of these could be determined by applying some important reactions of the carbonyl function like oxidation, reduction and condensation with the help of the reagents. In view of the fact that a large number of naturally occurring compounds contain this carbonyl function and quite a few synthetic or naturally occurring compounds are of practical and industrial importance. A detail survey of literature reveals that carlier analytical methods developed for the propose were mostly directed towards the determination of individual compounds like act acetone or formaldehyde. One such survey was published by Mitchell who covers references upto 1951. Although some of the methods are gravimetric. It has been found that volumetric or colorimetric methods are better and these frequently form the basis of the specific methods. Methods based on chromatography, spectrometry photometry or Polarography or mass spectrometry has been proposed form time to time and are frequently employed. Whereas most of the methods originally developed were available on macroscale. They have been modified for operations on the semi-micro and micro-scale determinations. Singgia and maxey introduced a specific sulphitesulphuric acid reagent which was found to be batter and was employed for several aldehydes in my experiment; I'm using potentiometric titration against alkali:

Methods based on oxidation can be applied to be carbonyl compounds which are aldehydic in nature and in the course of oxidation, the aldehydic function is oxidised to the carbonyl function silver oxide has been employed as an oxidant by several workers like Bailey andkaox, Mitchell and smith, Rush and Jobnson where in precipitated mercuryredissoved in iodine after the acidification with acetic acid followed by determination of the axcess iodine by titration against thiosulhate. Yaneagishi, Yokoo and Inoue also employed Nessler's reagent indirectly by adding hydrazine and measuring the liberated nitrogen gas. Acid or alkaline potassium Permanganate was first employed for the determination of chloral and was subsequently employed in other cases. Peroxytrifluoroacetic acid in ethylene chloride was subsequently applied for the determination by Howthrone Bag, Chauhan and Shukla. They first used ceric ammonium nitrate for the determination of few aldehydic compounds. Ammonium hexanitratocerate (iv) in 0.5 N nitric acid has also been used for the determination of certain organic compounds. A method for the small scale determination of carbonyl compounds employing ammonium hexatratocerate (iv) in nitric acid medium as the

A survey of literature revealed that ammonium hexanitratocerate (iv) has not been utilized for the determination of some aldehydic compounds. This encouraged me to study the reaction of ammonium hexanitratocerate (iv) on aldehydes a rapid method for the milligram determination of aldehydes has thus been evolved. 1-5 mg of the sample is taken in a reaction flask and the excess of ammonium hexanitratocerate (iv) is added to it. The contents are allowed to react for a certain reaction time at 50° on were bath 1-2 mg of solid Salicylaldehyde were taken in 150 ml conical flask, and 10 ml of 0.15 M ca (iv) reagent was added to it. Contents were shaken wall and allowed to react for twenty minutes at 50°C on water bath. The reaction was quenched by adding 10 ml of 1 M sulphuric acid and contents shaken for a minute. The unreacted Ce (iv) was titrated against 0.025 M ferrous ammonium sulphate using ferron indicator. A blank experiment was also run under identical condition. The molar ratio of Ce (IV) reagent and the salicyladehyde was calculated with the amount of the Ce (IV) reagent consumed for the sample, also and the molar ratio was calculated. (Table-1)

With the recomended procedure, the small scale determination of salicylaldehyde, vanillin, O- nitrobenzaldehyde, m- nitrobenzaldehyde, and p- nitrobenzaldehyde in Table 2,3,4,5 and 6 respectively. Now the reaction is quenched by adding 10 ml of 1M sulphuric acid and the unreacted Ce (IV) is determined by titrating it against ferrous ammonium sulphate using ferroin as indicator.

In an attempt to develop a quick and covenient method for the small scale determination of aldehydic of +1 in most of the cases.

For testing the quantitive validity of the reaction salicyladehde was taken as test sample. Different amount of the sample were allowed to react with varying amount of Ce (IV) reagent at 50º C for different intervals of reaction time. The strichiometry of the reaction was established for each samples and a possible course of reaction was suggested. On the basis of the reaction conditions developed for salicyladehyde the estimation of other aldehydes derivative like vanillin, O- nitrobenzaldehyde, m- nitrobenzaldehyde and P- nitrobenzaldehyde.

The stoichiometry of the reaction for salicyladehyde was established in the following ways:- Milligram determination of salicyladehyde with 0.15 M Ammonium hexanitratocerate (IV) in 0.5 N nitric acid.

Milligram determination of Vanillin with 0.15 M Ammonium hexanitratocerate(IV) in 0.5 N nitric acid.

0.15 M Ammonium hexanitratocerate (IV) in 0.5 N nitric acid.

TABLE-4

Milligram determination of m-nitrobenzaldehyde with 0.15 M ammonium hexanitratocerate (IV) in 0.05 N nitric acid. Reaction temperature 500 C

TABLE- 5

Milligram determination of p-nitrobenzaldehyde with 0.15 M ammonium hexanitratocerate (IV) in 0.05 N nitric acid. Reaction temperature 500 C

TABLE- 6

determination of salicylaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde, p- nitrobenzaldehyde & vanillia were achieved. The results given in the Table to were achieved. The results given in the Table to show that the percentage recovery of the sample is fairly constant with the varying sample amount. Taking salicyladehyde as the test sample the recommended experimental conditions were obtained by carrying out the reaction of the sample with Ce (IV) under different condition by varying reaction time, temp. And the amount of Ce (IV) agent and calculated the % recovery of the sample. The overall reaction for the oxidation of aldehydes may be represented in the following form. The reaction finds support from previous mechanism.

1. Mitchell, Jr. J.: (1953) Inorganic analysis, vol. 1, Interscience, New York, p. 243 2. Ripper, M.: (1900) Monatsch, 21, pp. 1979 – 85. 3. Lucas, J.F.C.: Rev. cienc. Apl. (Madrid) 8, 103 (1954) 4. Seyewetz, A. and Bardin, J.: (1905) Bull. soc.chim. 33, 1000

P.G. Department of Chemistry, Gaya College Gaya, Magadh University Bodh Gaya, Bihar