Computer-Aided Mechanism Elucidation of Acetylene Hydrocarboxylation to Acrylic Acid Based on a Novel Union of Empirical and Formal Methods

Abstract

In the elucidation of complex multistep reactions, it is easy to overlook significant mechanistic hypotheses. Hence, the use of computer programs to search for mechanisms is attractive, but these programs must respect the prior knowledge held by the investigator. Virtually all knowledge-based programs accommodate prior knowledge of either what can or what cannot happen, but there are advantages in exploiting both types of knowledge simultaneously. We report a novel alliance of two programs that enables these advantages and which represents an advance in the capabilities of computational chemistry, as illustrated here on the complex synthesis of acrylic acid from acetylene, CO, and water catalyzed by palladium complexes. The pathways reported by the programs were categorized as hydride, hydroxycarbonyl (alcoholate-like), and metallocyclic, the mechanistic types that are known from publications on hydrocarboxylation and hydrocarbalkoxylation of unsaturated molecules in solutions of transition metal complexes. Many specific pathways were not considered before in the absence of comprehensive computerized searches.

AlphaGo, Locked Strategies, and Eco-Cognitive Openness

“…4 A review of the classical AI approaches to abduction (mainly based on logic programming) is given by Paul [16] and Bylander et al, Reiter et al, de Kleer and Williams, Reggia et al [17][18][19][20] (set covering approaches). Other classical programs regarding discovery in science are illustrated by Valdés-Pérez [21]: MECHEM (reaction mechanisms in chemistry [22]), ARROSMITH (intertwining between drugs or dietary aspects and diseases in medicine [23]), GRAFFITI (generation of conjectures in graph theory and other mathematical areas [24]), MDP/KINSHIP (determination of classes within a classification in linguistics [25]). 5 Other computational programs that demonstrated their efficaciousness in the execution of machine discovery abductive tasks derived from the studies on genetic algorithms and evolving neural networks (cf.…”

“…Simply checking the Wikipedia entry DeepMind (https://en. wikipedia.org/wiki/DeepMind), 22 [DeepMind is a British artificial intelligence company instituted in September 2010 and took by Google in 2014, the company created the AlphaGo program], the following non-contested passage is reported, concerning the so-called "NHS data-sharing controversy":…”

“…In this article, I limit myself to deal with cognitive, logical, and epistemological aspects to the aim of introducing the distinction between locked and unlocked strategies and its meaning with respect to intelligent computation. 22 Date of access 10 of January, 2019. 23 Relatively recent bibliographic references can be found in my book [73].…”

Kinetic models of multi-route reactions in homogeneous catalysis with metal complexes (A Review)

“…There are well known formalized procedures (computer routines) for generating hypotheses (see, e.g., [75][76][77][78]). Methods for reduction of the complexity of hypotheses have been proposed and approaches to the analysis of large reaction networks have been developed [33,[79][80][81].…”

Mechanism of oxidative carbonylation of phenylacetylene and methylacetylene. Generation and experimental discrimination of hypotheses

“…RCttCCu + R'COCl ~ ~OR' + CuCl (5) The formation of intermediates in mechanisms . t4 Therefore, the first two hypotheses can be related to the schemes of the "alcoholate'-or "alkoxycarbonyi'-type mechanisms.…”