# Continuous Production of Methyl Lactate from Hemicellulosic Sugars: Identifying and Sorting out Sn-USY-Based Catalyst Deactivation

## TL;DR

Scientists developed a catalyst to continuously produce methyl lactate from sugars, but found ways to prevent its breakdown during the process.

## Contribution

The study identifies and mitigates deactivation mechanisms in a [K]Sn-USY catalyst for methyl lactate production.

## Key findings

- Potassium leaching and organic deposition are key causes of catalyst deactivation.
- Adding small amounts of potassium stabilizes the catalyst for over 140 hours.
- The catalyst achieves over 30% methyl lactate yield from hemicellulose hydrolysates.

## Abstract

Potassium-exchanged
tin-functionalized USY zeolite ([K]­Sn-USY)
has been studied in the continuous transformation of glucose, xylose,
and their mixtures in a fixed-bed reactor for the production of methyl
lactate at 150 °C. The catalyst efficiently drives the transformation
of all the studied substrates, though it faces several deactivation
mechanisms, especially in the case of hexoses. Potassium leaching
from the catalyst and organic deposition adduced to furanics produced
during the reaction were ascribed as the major deactivation causes.
The addition of small amounts (10 mg/kg) of potassium (as KCl or KOH)
alleviated the catalyst deactivation, allowing the latter stable methyl
lactate production over 30% yield for over 140 h from individual carbohydrates
and complex sugar mixtures like Scots Pine hemicellulose hydrolysates.