Some observations on the dimedone method for the gravimetric determination of formaldehyde

✍ Scribed by D. Spencer; T. Henshall

• Publisher: Elsevier Science
• Year: 1954
• Tongue: English
• Weight: 177 KB
• Volume: 11
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)87761-2

✦ Synopsis

Ko~_I-I~~FI: AND STENGEIZ~ describe a method for the determination of formaldehyde in aqueous solution in which I ,3,1',3'-tetrakcto-5,5,5',5'-tetramethyl-4-4'-clicyclohexylmcthane, the condensation product of formaldehyde and dimcdone

(5,~~dimetl~ylcyclol~exane-dionc -1,3), is filtered and either weighed or cstimatcd by alkali titration.

However, they consider that the details as given by VORLAN~ER~ and on which their method is based are inadequate, and that a further investigation is dcsirahlc. A lcinctic study of this reaction has been undertake+, the results of which will be published elsewhere. It has been found that the rate of this reaction is immeasurably slow in strongly acid solution, but increases to a maximum at per 8.5, and that the product can bc quantitatively precipitated from the reaction mixture by the addition of excess concentrated hydrochloric acid. The variation with prr of the second order rate constant at 25°C is shown in Table , whilst Table shows the temperature dependence of the rate constant as obtained from measurements in o.ogM potassium hydrogen phthalatc buffer solution which has a very small PIE -temperature coefficient.