Mathematical modeling and multiobjective optimization complex catalyst hydroalumination reaction of olefins with diisobutylaluminium hydride

A mathematical model for the catalyst hydroalumination reaction of olefins with diisobutylaluminium hydride has been developed. In solving the direct kinetic problem applies multi-step method Gere variable order. When solving systems of ordinary differential equations in chemical kinetics, it is necessary to fulfill the balance relations at each sampling point. That ensures the fulfillment of the law of conservation of matter and the convergence of the numerical method. For the catalytic reaction of hydroalumination olefins in the presence of the organoaluminum compound diisobutylaluminum hydride, the problem of multicriteria optimization reaction conditions was solved based on a detailed kinetic model. The solutions found make it possible to optimally select the reaction conditions to achieve the maximum yield of target products, which can be based on the subsequent introduction of the laboratory reaction into production.

Ni-Catalyzed Carboxylation of Conjugated Dienes with Carbon Dioxide and DIBAL-H for the Synthesis of ß,γ-Unsaturated Carboxylic Acids

Ni-catalyst-promoted conjugated dienes undergo 1,2-hydrocarboxylation with carbon dioxide under atmospheric pressure and in the presence of diisobutylaluminum hydride (DIBAL-H). Conjugated dienes react with carbon dioxide in a 1:1 ratio to produce the corresponding β,γ-unsaturated carboxylic acids without suffering from the dimerization or oligomerization of conjugated dienes.

SEARCH FOR THE OPTIMAL VALUE OF THE INITIAL CONCENTRATION OF DIISOBUTYLALUMINUM HYDRIDE FOR THE REGULATION OF THE POLYISOPRENE MOLECULAR MASS ON A NEODYMIUM-CONTAINING CATALYTIC SYSTEM

Статья посвящена нахождению оптимального значения начальной концентрации диизобутилалюминийгидрида для полимеризации изопрена на неодимсодержащей каталитической системе. Для исследования закономерностей протекания процесса полимеризации изопрена построена кинетическая модель, то есть система обыкновенных дифференциальных уравнений, выражающих динамику концентраций частиц, участвующих в процессе. Система дифференциальных уравнений высокой размерности сведена к конечному виду путем применения метода моментов. Приведена в общем виде постановка задачи поиска оптимальных значений начальных концентраций веществ химического процесса. В качестве метода решения поставленной оптимизационной задачи в работе использованы эволюционные методы, в основе одного из которых лежит генетический алгоритм. Проведен вычислительный эксперимент для процесса полимеризации изопрена по поиску оптимального значения начальной концентрации диизобутилалюминийгидрида с целью регулирования молекулярной массы полиизопрена. Показано, что рассчитанное значение концентрации диизобутилалюминийгидрида обеспечивает достижение заданного критерия оптимальности. The article is devoted to finding the optimal value of the initial concentration of diisobutylaluminum hydride for the polymerization of isoprene on a neodymium-containing catalyst system. The authors present a kinetic diagram of the polymerization of isoprene on a neodymium-containing catalyst system using two types of organoaluminum compounds: triisobutylaluminum and diisobutylaluminum hydride. To study the patterns of the polymerization of isoprene, a kinetic model is constructed, that is, a system of ordinary differential equations expressing the dynamics of the concentration of particles involved in the process. The system of high-dimensional differential equations is reduced to the final form by applying the method of moments. The general statement of the problem of finding the optimal values of the initial concentrations of the substances of the chemical process is given. As a method for solving the optimization problem posed, evolutionary methods are used in the work, one of which is based on a genetic algorithm. A computational experiment was conducted for the polymerization of isoprene to find the optimal value of the initial concentration of diisobutylaluminum hydride in order to control the molecular weight of polyisoprene. It is shown that the calculated value of the concentration of diisobutylaluminium hydride provides achievement of the specified optimality criterion.

Low-temperature reduction of acyclic carvomentholactone derivatives with diisobutylaluminum hydride in methylene chloride

Earlier, we discovered a novel reaction in the chemistry of organoaluminum compounds - the formation of O-isobutyl acetals during low-temperature (-70 °С) treatment of a number of seven-membered lactones with a twofold (or more) molar amount of diisobutylaluminium hydride in methylene chloride. In addition, it was shown that the acyclic derivatives of (-)-mentholactone - methyl 6-hydroxy-3,7-dimethyl-octanoate and its 6-oxo analogue - also enter into the low-temperature reduction reaction of diisobutylaluminum hydride in methylene chloride. Moreover, methyl 6-hydroxy-3,7-dimethyloctanoate in this reaction behaves similarly to (-)-mentholactone: when 4 equivalents of diisobutylaluminium hydride acts on it, the reaction proceeds with the predominant formation of isobutyl acetal as the only (2S,7S)-epimer. Methyl 6-oxo-3,7-dimethyl octanoate in a low-temperature reduction reaction with 4 equivalents of diisobutylaluminium hydride in methylene chloride acts as a mixture of (-)-mentholactone and isomentolactone, leading to a mixture of (2S,7S)-, (2S,7R)- and (2R,7R)-isobutyl acetals in a ratio of 3.2: 1.3: 1.0, respectively. In the present work, when low-temperature reduction was involved in the reaction with diisobutylaluminium hydride, methyl (3R)-6-hydroxy- or (3R)-6-oxo-3-isopropylheptanoates available from carvomentolactone reacted without the formation of isobutyl acetal: a mixture of (2: 1) 6-hydroxy-(3R)-isopropylheptanal and (4R)-isopropyl-7-methyloxepan-2-ol was obtained.