Estudio del proceso de obtención de vainillina a partir de lignina mediante un proceso asistido con microondas : Efecto del tiempo sobre la obtención de vainillina a partir de lignina en un proceso asistido con microondas.

Abstract

The aim of this research was to study the effect of time in obtaining vanillin from lignin, through a process carried out in a microwave-assisted synthesis reactor. For this, the oxidation of technical grade lignin was carried out using calcium hydroxide and sodium hydroxide. Three different levels were analyzed (1, 2 and 3 hours), each with two replicates. The analysis of the resulting samples was carried out by high-performance liquid chromatography (HPLC), from which the concentration and yield of vanillin could be determined. This methodology was also applied to lignin derived from a Kraft process with guadua cane (bamboo).

After the statistical analysis of the results, it was possible to conclude that time is a parameter that significantly influenced on the obtaining of vanillin, and that the higher concentration was achieved after 3 h of reaction. The reason might be that the lignin molecule was subjected to drastic pH and temperature conditions for a longer period. In addition, electromagnetic waves were used to heat the reaction mix, which could facilitate the fractionation of the lignin molecule and the oxidation of its monomers. The yields obtained in this process were not as high as the yields reported in similar works, which could have been produced by several factors such as the oxidizing agent, the control of the operating pressure and the volatility of the solvent.