Hydration of cyclohexene with solid acid catalysts

Feasibility Analysis for the Direct Hydration of 1-Octene in a Catalytic Distillation Process Using Residual Curve Maps

The very useful organic solvent 2-octanol is widely employed in the industry, and the direct hydration of olefins is an important method for its production. However, a slow transfer rate during a reaction due to the poor mutual solubility of the reactants is a problem; a cosolvent can be used to solve it. In this study, the feasibility of using the direct hydration of 1-octene via a catalytic distillation process using 1,4-dioxane as a cosolvent was investigated. First, the COSMOtherm program was used to identify and screen many typical cosolvents. Subsequently, the kinetics of the direct hydration reaction of 1-octene using 1,4-dioxane as a cosolvent and an HZSM-5 molecular sieve as the catalyst were determined experimentally. Finally, kinetic and thermodynamic models were utilized to create non-reactive and reactive residual curve maps to assess the feasibility of proceeding with the reaction. Applying a suitable Damköhler number (Da) value and the residual curve changes demonstrated that proceeding with the process was reasonable and feasible. For 0 < Da < 0.03, the reaction kinetics drove the process and 2-octanol was produced via a reaction distillation column procedure. Lastly, two conceptual design processes for the synthesis process of 2-octanol catalytic distillation were proposed and the related analysis carried out.

Hydrogen-Catalyzed Acid Transformation for the Hydration of Alkenes and Epoxy Alkanes over Co-N Frustrated Lewis Pair Surfaces

Hydrogen (H₂) is widely used as a reductant for many hydrogenation reactions; however, it has not been recognized as a catalyst for the acid transformation of active sites on solid surface. Here, we report the H₂-promoted hydration of alkenes (such as styrenes and cyclic alkenes) and epoxy alkanes over single-atom Co-dispersed nitrogen-doped carbon (Co-NC) via a transformation mechanism of acid-base sites. Specifically, the specific catalytic activity and selectivity of Co-NC are superior to those of classical solid acids (acidic zeolites and resins) per micromole of acid, whereas the hydration catalysis does not take place under a nitrogen atmosphere. Detailed investigations indicate that H₂ can be heterolyzed on the Co-N bond to form H^δ--Co-N-H^δ+ and then be converted into OH^δ--Co-N-H^δ+ accompanied by H₂ generation via a H₂O-mediated path, which significantly reduces the activation energy for hydration reactions. This work not only provides a novel catalytic method for hydration reactions but also removes the conceptual barriers between hydrogenation and acid catalysis.

The green and sustainable synthesis of nanometer ZSM-5 without organotemplates via utilizing the recycled mother liquid

A formation mechanism of nanometer ZSM-5 aggregates using the recycled mother liquid and seed-assistance is proposed.