The nature of autocatalysis in the Butlerov reaction

Catalytic Formation of Monosaccharides: From the Formose Reaction towards Selective Synthesis

“…The first hypothesis on the autocatalytic nature of the FR was put forward in 1924 after the discovery of a notable increase in the rate of the process upon addition of the formose product to the initial reaction mixture. [16] Further, it was revealed that the induction period, which is typical of the kinetics of the FR (see [17,18] and Figure 1), is eliminated or notably shortened upon introduction of small amounts of particular organic compounds. Namely, higher and lower monosaccharides, benzoin and its derivatives, malic acid, ethoxyacetaldehyde, and acetoin stimulate conversion of formaldehyde to carbohydrates, while polyols, acetone, pentaacetylfructose, or polysaccharides exert no influence on the duration of the induction period of the FR.…”

“…However, it was found later that this ability is not compulsory for the initiators of the FR. The nature of organic co-catalysts impacts the duration of the induction period only but does not alter the rate of the monosaccharides formation [17,18,20] or the composition of the product mixture. [17,18,21] In 1980, it was postulated that the FR does not proceed at all in the absence of organic co-catalysts; that is, the presence of the latter determines not only the duration of the induction period, but also is mandatory for the initiation of the synthesis of monosaccharides from formaldehyde.…”

“…The nature of organic co-catalysts impacts the duration of the induction period only but does not alter the rate of the monosaccharides formation [17,18,20] or the composition of the product mixture. [17,18,21] In 1980, it was postulated that the FR does not proceed at all in the absence of organic co-catalysts; that is, the presence of the latter determines not only the duration of the induction period, but also is mandatory for the initiation of the synthesis of monosaccharides from formaldehyde. [22] The incompatibility of this finding with the results published previously (e.g., [3,12,13] ) was explained by the insufficient purity of the initial formaldehyde solution used for the experiments by the authors who claimed the possibility of self-condensing of two molecules of formaldehyde into glycolaldehyde under the action of a base catalyst.…”

“…[21] Indeed, a too high concentration of the fructose or arabinose co-catalyst in the reaction mixture results in a decrease in the rate of monosaccharides formation over calcium hydroxide, [21] although both substances are known as active initiators of the FR. [17,18,24,25] This unexpected inhibition effect might be explained by partial transformation of the excess initiator into acids (vide infra Section 3.3) which deplete the alkaline catalyst and decelerate the rate of the aldolization of formaldehyde.…”

A Chemical Engineering Perspective on the Origins of Life

“…In general, a large number of products were produced in the Miller-Urey experiments and in most subsequent experiments from mixtures of a few simple chemicals. The formose reaction produces ribose from formaldehyde, but it also produces a large number of other products [69]. Catalysts are needed for the formose reaction, and the nature of the catalyst influences the distribution of products [70].…”