# Synthesis of 3-methyl-3-buten-1-ol by supercritical CO2 in coordination with HZSM-5-catalyzed formaldehyde-isobutene Prins reaction

## TL;DR

This paper explores using supercritical CO2 and a modified catalyst to efficiently produce 3-methyl-3-buten-1-ol from formaldehyde and isobutene.

## Contribution

The study introduces a novel catalytic system combining supercritical CO2 and CsH2PO4-modified HZSM-5 for enhanced Prins reaction efficiency.

## Key findings

- Supercritical CO2 activates formaldehyde into carbon-positive ions, improving reaction efficiency.
- Alkaline sites on the catalyst extract α-H from isobutene to form carbon-negative ions.
- The combination of catalyst and supercritical CO2 enhances the Prins reaction reactivity.

## Abstract

The reaction solvent and catalyst play essential roles in the Prins reaction for the synthesis of 3-methyl-3-buten-1-ol (MBO) from formaldehyde and isobutene. The reactivity of the solid base-catalyzed Prins condensation reaction by formaldehyde and isobutene in supercritical CO2 was investigated using CsH2PO4-modified HZSM-5. We found that the alkaline sites of the alkali-loaded catalyst could extract the α-H on isobutene to generate olefin carbon-negative ions, while the supercritical CO2 with weak Lewis acidity could activate formaldehyde to carbon-positive ions, which can combine more easily with carbon-negative isobutene to react, thus improving the reactivity of the reaction system.