Search results for "VANILLIN"

Anodic Degradation of Lignin at Active Transition Metal-based Alloys and Performance-enhanced Anodes

2018

One-Pot, Clean Synthesis of Vanillic Acid from Ferulic Acid

2016

Ferulic acid dissolved in water is selectively oxidized to vanillic acid in high yield (≈60 %) under remarkably mild and green conditions, namely at room temperature with air as primary oxidant, over a catalytic amount of nanostructured Bi2WO6. The process is general and opens the route to the selective oxidation of natural substances into derivatives of significant applicative relevance.

Quantitative evaluation of the phenolic profile in fruits of six avocado (Persea americana) cultivars by ultra-high-performance liquid chromatography…

2016

The phenolic profiles of six varieties of avocado (Persea americana) grown in Sicily were investigated. The ultra-high-performance liquid chromatography-heated electrospray-mass spectrometry method was developed to determine qualitative and quantitative changes in fruits at two different ripening stage. Nineteen individual phenolic compounds were detected in avocado pulp extracts. Gallic acid, sinapinic acid, vanillin, p-coumaric acid, and gentisic acid were present only in ripe fruits. On the contrary, epicatechin decreased with fruit ripening, whereas protocatechuic acid, 4-hydroxybenzoic acid, chlorogenic acid, and benzoic acid were relatively stable or exhibited erratic changes with fru…

Tuning The Selectivity To Aldehyde Via Ph Regulation In The Photocatalytic Oxidation Of 4-Methoxybenzyl Alcohol And Vanillyl Alcohol By Tio2 Catalysts

2021

Abstract The influence of pH on the photocatalytic partial oxidation of 4-methoxybenzyl alcohol (MBA) and vanillyl alcohol (VA) to their corresponding aldehydes in aqueous suspension under UVA irradiation was investigated by using poorly crystalline home-prepared and crystalline commercial TiO2 (BDH, Merck and Degussa P25) photocatalysts. The results clearly show as tuning pH can strongly impart selectivity and activity to photocatalytic processes which are often quite unselective in aqueous suspensions. It was found that pH effect on reaction rate and product selectivity strongly depended on TiO2 crystallinity and substrate type. In the case of MBA oxidation, photoreactivity and selectivit…

Sorption behavior of volatile phenols at the oak wood/wine interface in a model system.

2006

The sorption in a model system of aroma compounds of enological interest (mixture of the eight derivatives from guaiacol, 4-ethylphenol, and whiskylactone) onto wood was investigated to assess the influence of wood on the concentration of these volatiles during the aging of wine. To evaluate the influence of the solubility of aroma compounds in sorption phenomena, this parameter was determined for each volatile compound in model wine at 10 and 25 degrees C. The solubility is significantly higher in the model wine than in water and remains constant in the range of temperatures studied, except for guaiacol and vanillin. Kinetic and equilibrium sorptions were investigated. Sorption kinetics sh…

Highly selective generation of vanillin by anodic degradation of lignin: a combined approach of electrochemistry and product isolation by adsorption

2015

The oxidative degradation of lignin into a variety of valuable products has been under investigation since the first half of the last century. Especially, the chance to claim this cheap, abundant and renewable source for the production of the important aroma chemical vanillin (1) was one of the major driving forces of lignin research. So far most of the developed methods fail in technical application since no viable concept for work-up is included. This work represents a combined approach of electrochemical conversion of Kraft lignin and product recovery by adsorption on a strongly basic anion exchange resin. Electrolysis conditions are optimized regarding reaction temperatures below 100 °C…

Preparation of fouling resistant and highly perm-selective novel PSf/GO-vanillin nanofiltration membrane for efficient water purification

2022

International audience; To meet the rising global demand for water, it is necessary to develop membranes capable of efficiently purifying contaminated water sources. Herein, we report a series of novel polysulfone (PSf)/GO-vanillin nanofiltration membranes highly permeable, selective, and fouling resistant. The membranes are composed of two-dimensional (2D) graphite oxide (GO) layers embedded with vanillin as porogen and PSf as the base polymer. There is a growing interest in addressing the synergistic effect of GO and vanillin on improving the permeability and antifouling characteristics of membranes. Various spectroscopic and microscopic techniques were used to perform detailed physicoche…

Improvement of membrane performances to enhance the yield of vanillin in a pervaporation reactor.

2014

In membrane reactors, the interaction of reaction and membrane separation can be exploited to achieve a “process intensification”, a key objective of sustainable development. In the present work, the properties that the membrane must have to obtain this result in a pervaporation reactor are analyzed and discussed. Then, the methods to enhance these properties are investigated for the photocatalytic synthesis of vanillin, which represents a case where the recovery from the reactor of vanillin by means of pervaporation while it is produced allows a substantial improvement of the yield, since its further oxidation is thus prevented. To this end, the phenomena that control the permeation of bot…

Preparation of novel high permeability and antifouling polysulfone-vanillin membrane

2020

International audience; A novel high-performance nanofiltration membrane was fabricated by a simple and scalable route involving in situ cross-linking of hydrophilic, cheap, and environmentally friendly vanillin as antifouling agent with polysulfone (PSf) for salt rejection performance. Vanillin acts as a porogen, which induces a negative surface charge on the membrane surface due to the presence of polar functional groups like alcohol and aldehyde. The surface properties, including charge, morphology, and hydrophilicity, were investigated in detail using analytical instruments. The nanofiltration performance of the fabricated PSf-vanillin membranes was dependent on the percentage of vanill…

A PERVAPORATION PHOTOCATALYTIC REACTOR FOR THE GREEN SYNTHESIS OF VANILLIN

2012

Abstract Pervaporation is the ideal membrane separation process to be coupled with photocatalysis for the green synthesis of vanillin from ferulic acid. In fact the operative conditions of the two processes are absolutely congruent and the integration is straightforward even operating with separate equipments. The utilization of a highly selective membrane allows the continuous recovery of vanillin by pervaporation from the reacting solution, so that its oxidative degradation is largely avoided and the yield is substantially enhanced. The effects of the main parameters are analyzed resorting to a mathematical model, which is validated by a comparison with the experimental data. In particula…