Supported Rare Earth Catalyst for Hydrocarbon C-H Borylation
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Solution Overview
Problem
Current methods for hydrocarbon C—H borylation are limited by the dominance of late metal catalysts and lack of efficient rare earth element catalysts, particularly for accessing new mechanisms or selectivity, with rare earth-catalyzed borylation being underdeveloped and catalyst deactivation issues.
Innovation Solution
A supported rare earth-catalyst system comprising a metal oxide support with Brønsted acid sites and a rare earth element-catalyst, where the rare earth element is bound to the Brønsted acid sites, and a method involving capping agents to produce a catalyst capable of mediating hydrocarbon borylation with pinacolborane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If late metal catalysts are used for C-H borylation, then catalytic efficiency is achieved, but catalyst cost and scarcity increase
Solution Approach 1:
The patent replaces expensive, scarce late metal catalysts (Group 9 organometallics) with cheaper, abundant rare earth element catalysts (lanthanum, scandium, yttrium) that can be used in practical applications. The supported rare earth borohydride catalysts provide a cost-effective alternative while maintaining catalytic functionality for C-H borylation reactions.
Solution Approach 2:
The patent changes the fundamental parameter of catalyst composition from late transition metals to rare earth elements, fundamentally altering the catalytic system's properties. This parameter change enables access to new reaction mechanisms (σ-bond metathesis) while reducing catalyst cost and scarcity.
2Quantity of substance
If rare earth element catalysts are used for C-H borylation, then catalyst cost decreases, but catalytic activity and stability are insufficient
Solution Approach 1:
The patent creates composite catalyst systems by supporting rare earth borohydrides on metal oxide supports. This composite structure combines the advantages of rare earth elements (cost-effectiveness) with the benefits of supported catalysts (enhanced stability and reusability), resolving the contradiction between low cost and sufficient activity/stability.
Solution Approach 2:
The metal oxide support acts as an intermediary that stabilizes the rare earth borohydride catalyst, preventing decomposition and deactivation. The support provides a stable platform that maintains catalyst activity over multiple reaction cycles, enabling practical applications of cost-effective rare earth catalysts.
3Reliability
If supported rare earth catalyst system is implemented, then catalytic stability is improved, but device complexity increases
Solution Approach 1:
The patent employs preliminary preparation of the metal oxide support with specific surface properties before introducing the rare earth borohydride. This preliminary action (support preparation) simplifies the overall process by ensuring optimal catalyst-support interactions from the outset, reducing complexity in subsequent steps while maximizing catalytic stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves a turnover number of 282 and 25% yield of phenyl pinacolborane, demonstrating a complementary approach to precious-metal catalyzed borylations and tolerating elevated temperatures for efficient C—H bond activations.
Implementation Method 1
catalyzed (Corker et al., 'Catalytic Cleavage of the C—H and C—C Bonds of Alkanes by Surface Organometallic Chemistry: An EXAFS and IR Characterization of a Zr—H Catalyst,'Science 271:966-969 (1996); Sadow et al., 'Catalytic Functionalization of Hydrocarbons by σ-Bond-Metathesis Chemistry: Dehydrosilylation of Methane with a Scandium Catalyst,'Angew. Chem. Int. Edit. 42:803-805 (2003)) via elementary σ-bond metathesis reactions
Implementation Method 2
The rare earth element-catalyst is bound to the Brønsted acid sites on the metal oxide support
Data Source
AI summary
The present application is directed to a supported rare earth-catalyst. This catalyst comprises a metal oxide support having Brønsted acid sites and a rare earth element-catalyst. The rare earth element-catalyst is bound to the Brønsted acid sites on the metal oxide support. The present application is also directed to methods of making supported rare earth-catalyst and methods for borylation of hydrocarbons using the supported rare earth-catalyst.