Preparação, caracterização e estudo da atividade catalítica de catalisadores heterogêneos de níquel em resolução cinética dinâmica de aminas: uma revisão
Data
2023-11-30
Autores
Hipólito, Giovanna Milena Borges 
Orientadores
Siqueira, Fernanda Amaral de
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A produção de compostos enantiomericamente puros é importante para as indústrias farmacêuticas e agroquímicas. Um dos métodos mais utilizados para esta finalidade, partindo, principalmente, de álcoois secundários e aminas primárias, é a Resolução Cinética Dinâmica (RCD). Esta reação ocorre em duas etapas: a primeira é a resolução – que pode ser catalisada por uma enzima que é responsável pela conversão enantiosseletiva a partir de uma mistura racêmica. A segunda etapa constitui na racemização do enantiômero remanescente por um catalisador metálico. Dentre esses catalisadores, a maioria contém metais de alto valor agregado. Verifica-se que os de níquel, que são de menor custo e são fortemente utilizados em diferentes aplicações, foram pouco explorados nesta metodologia até o momento. Estudos recentes trazem o uso de catalisadores de níquel nas reações de RCD. Com isso, este trabalho teve como objetivo realizar uma revisão bibliográfica sistemática acerca dos estudos da preparação e técnicas de caraterização de catalisadores heterogêneos de níquel, assim como da análise de sua atividade catalítica em reações de resolução cinética dinâmica de diferentes aminas. A partir de bases de dados e palavras-chave especificadas neste trabalho, coletou-se 151 trabalhos e artigos publicados. Com uma leitura mais atenta dos resumos dos trabalhos, principalmente, foram selecionados 75 deles para compor a revisão. De acordo com a análise dos trabalhos selecionados, as técnicas de caracterização dos catalisadores de níquel foram eficientes, e os métodos de sua preparação foram diversos. Com relação às reações propriamente ditas, os melhores resultados foram atingidos sob temperaturas entre 70-80 °C, com agente acilante de moléculas menos volumosas e com tempo de duração menor (24 horas). O solvente a ser utilizado deve ser apolar, de preferência, e o suporte do catalisador deve ter caráter básico. Os catalisadores de níquel desempenharam de forma satisfatória nas RCDs. Os valores de conversão obtidos nos trabalhos selecionados atingiram 78 %. Poucos trabalhos com o uso do níquel em RCDs foram encontrados. Uma das razões pode ser a maior facilidade deste metal sofrer oxidação comparado a outros metais de transição. Para a produção de compostos enantiomericamente puros, a utilização de níquel na etapa de racemização de aminas continua sendo alvo de estudos na busca por altos valores de conversão e rendimento.
The production of enantiomerically pure compounds is important for the pharmaceutical and agrochemical industries. One of the most used methods for this purpose, starting mainly from secondary alcohols and primary amines, is Dynamic Kinetic Resolution (DKR). This reaction occurs in two steps: the first is resolution – which can be catalyzed by an enzyme that is responsible for the enantioselective conversion from a racemic mixture. The second step involves the racemization of the remaining enantiomer by a metal catalyst. Among these catalysts, the majority contain metals with high added value. It appears that nickel ones, which are lower in cost and are heavily used in different applications, have been little explored in this methodology to date. Recent studies bring the use of nickel catalysts in DKR reactions. Therefore, this work aimed to carry out a systematic bibliographical review on studies on the preparation and characterization techniques of heterogeneous nickel catalysts, as well as the analysis of their catalytic activity in dynamic kinetic resolution reactions of different amines. From databases and keywords specified in this work, 151 published works and articles were collected. With a more careful reading of the abstracts of the works, mainly 75 of them were selected to compose the review. According to the analysis of the selected works, the techniques for characterizing nickel catalysts were efficient, and the methods for their preparation were diverse. Regarding the reactions themselves, the best results were achieved at temperatures between 70-80 °C, with an acylating agent of less bulky molecules and with a shorter duration (24 hours). The solvent to be used must preferably be nonpolar, and the catalyst support must be basic in nature. Nickel catalysts performed satisfactorily in DKRs. The conversion values obtained in the selected works reached 78 %. Few studies on the use of nickel in DKRs were found. One of the reasons may be that this metal is more easily oxidized compared to other transition metals. For the production of enantiomerically pure compounds, the use of nickel in the amine racemization step continues to be the subject of studies in the search for high conversion and yield values.
The production of enantiomerically pure compounds is important for the pharmaceutical and agrochemical industries. One of the most used methods for this purpose, starting mainly from secondary alcohols and primary amines, is Dynamic Kinetic Resolution (DKR). This reaction occurs in two steps: the first is resolution – which can be catalyzed by an enzyme that is responsible for the enantioselective conversion from a racemic mixture. The second step involves the racemization of the remaining enantiomer by a metal catalyst. Among these catalysts, the majority contain metals with high added value. It appears that nickel ones, which are lower in cost and are heavily used in different applications, have been little explored in this methodology to date. Recent studies bring the use of nickel catalysts in DKR reactions. Therefore, this work aimed to carry out a systematic bibliographical review on studies on the preparation and characterization techniques of heterogeneous nickel catalysts, as well as the analysis of their catalytic activity in dynamic kinetic resolution reactions of different amines. From databases and keywords specified in this work, 151 published works and articles were collected. With a more careful reading of the abstracts of the works, mainly 75 of them were selected to compose the review. According to the analysis of the selected works, the techniques for characterizing nickel catalysts were efficient, and the methods for their preparation were diverse. Regarding the reactions themselves, the best results were achieved at temperatures between 70-80 °C, with an acylating agent of less bulky molecules and with a shorter duration (24 hours). The solvent to be used must preferably be nonpolar, and the catalyst support must be basic in nature. Nickel catalysts performed satisfactorily in DKRs. The conversion values obtained in the selected works reached 78 %. Few studies on the use of nickel in DKRs were found. One of the reasons may be that this metal is more easily oxidized compared to other transition metals. For the production of enantiomerically pure compounds, the use of nickel in the amine racemization step continues to be the subject of studies in the search for high conversion and yield values.