Green Synthesis of Veratraldehyde Using Potassium Promoted Lanthanum–Magnesium Mixed Oxide Catalyst

 Abstract Image

Veratraldehyde is an important chemical used in perfumery, agrochemical, and pharmaceutical industries. Current processes of manufacture of veratraldehyde use homogeneous catalysts, which make them highly polluting, creating problems of disposal of effluents and product purity. In the current work, veratraldehyde was synthesized from O-alkylation of vanillin with an environmentally benign reagent, dimethyl carbonate. A series of potassium loaded La2O3–MgO were prepared by the incipient wetness impregnation method, and their performance was evaluated vis-à-vis MgO, La2O3, La2O3–MgO, and a series of 1–4 wt % K/La2O3–MgO. All catalysts were characterized by different techniques, such as N2 adsorption/desorption, XRD, TGA-DSC, FT-IR, CO2-TPD, and SEM techniques. The effect of different loadings (1–4 wt %) of potassium on La2O3–MgO was studied, among which 2 wt % K/La2O3–MgO showed the best activity and selectivity due to high dispersion of potassium and high basicity in comparison with the rest. The activity of 2 wt % K/La2O3–MgO in O-methylation of vanillin with dimethyl carbonate (DMC) was closely associated with basicity. Various parameters were studied to achieve the maximum yield of the desired product. The maximum conversion was found with catalyst loading of 0.03 g/cm3 and mole ratio of vanillin and DMC of 1:15 at 160 °C in 2 h. The reaction follows pseudo-first-order kinetics for the O-methylation of vanillin. The energy of activation was found to be 13.5 kcal/mol. Scale-up was done using the kinetic model to observe that the process could be scaled up using the process parameters. The overall process is clean and green.

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Green Synthesis of Veratraldehyde Using Potassium Promoted Lanthanum–Magnesium Mixed Oxide Catalyst

Department of Chemical Engineering, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga Mumbai-400 019, India
Org. Process Res. Dev., Article ASAP
DOI: 10.1021/acs.oprd.7b00127
*E-mail: gd.yadav@ictmumbai.edu.in, Phone: +91-22-3361-1001, Fax: +91-22-3361-1020; +91-22-3361-1002.

Conclusion


Synthesis of veratraldehyde using a catalytic green process is desirable in today’s environmentally conscious world. Therefore, a new process was devised in this work using a novel catalyst using mixed metal oxides. Different loadings of potassium promoted on La2O3–MgO (1–4 wt %) catalysts were synthesized and characterized by various techniques. The activity of catalyst was studied in the reaction of vanillin with DMC for the synthesis of veratraldehyde in comparison with several other catalysts, such as MgO, La2O3, La2O3–MgO, 1 wt % K/La2O3–MgO, 2 wt % K/La2O3–MgO, 3 wt % K/La2O3–MgO, and 4 wt % K/La2O3–MgO. Potassium promoted mixed oxides showed much higher catalytic activity than the corresponding pure La2O3–MgO mixed oxide, due to an increase in moderate, strong, superbasic sites. Moreover, loading of potassium on La2O3–MgO changes the structural properties, such as pore volume and surface area, and it gives higher conversion toward the desired product. Two wt % K/La2O3–MgO is the best and gives 96% of conversion at mole ratio 1:15 of vanillin to DMC and 0.03 g/cm3 catalyst loading at 160 °C. By using this catalyst, we studied various parameters systematically to establish kinetics. The catalyst is reusable up to four cycles. The energy of activation for O-methylation of vanillin was found to be 13.5 kcal/mol. A scale up was also attempted. Experimental and theoretical values matched very well. The process is green and clean.
Jayaram Molleti
Institute Of Chemical Technology
Department of Chemical Engineering, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga Mumbai-400 019, India
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Prof. GD Yadav, Vice-Chancellor, ICT, Mumbai
*E-mail: gd.yadav@ictmumbai.edu.in, Phone: +91-22-3361-1001, Fax: +91-22-3361-1020; +91-22-3361-1002.
Institute Of Chemical Technology
Department of Chemical Engineering, Institute of Chemical Technology, Nathalal Parekh Marg, Matunga Mumbai-400 019, India

Is water a suitable solvent for the catalytic amination of alcohols?

Is water a suitable solvent for the catalytic amination of alcohols?

Green Chem., 2017, 19,2839-2845
DOI: 10.1039/C7GC00422B, Paper
Johannes Niemeier, Rebecca V. Engel, Marcus Rose
The catalytic aqueous-phase amination of biogenic alcohols with solid catalysts is reported for future development of renewable amine value-added chains.

Green Chemistry

Is water a suitable solvent for the catalytic amination of alcohols?

Abstract

The catalytic conversion of biomass and biogenic platform chemicals typically requires the use of solvents. Water is present already in the raw materials and in most cases a suitable solvent for the typically highly polar substrates. Hence, the development of novel catalytic routes for further processing would profit from the optimization of the reaction conditions in the aqueous phase mainly for energetic reasons by avoiding the initial water separation. Herein, we report the amination of biogenic alcohols in aqueous solutions using solid Ru-based catalysts and ammonia as a reactant. The influence of different support materials and bimetallic catalysts is investigated for the amination of isomannide as a biogenic diol. Most importantly, the transferability of the reaction conditions to various other primary and secondary alcohols is successfully proved. Hence, water appears to be a suitable solvent for the sustainable production of biogenic amines and offers great potential for further process development.

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Selective hydrogenation of N-heterocyclic compounds using Ru nanocatalysts in ionic liquids

Selective hydrogenation of N-heterocyclic compounds using Ru nanocatalysts in ionic liquids

Green Chem., 2017, 19,2762-2767
DOI: 10.1039/C7GC00513J, Communication
Hannelore Konnerth, Martin H. G. Prechtl
N-Heterocyclic compounds have been tested in the selective hydrogenation catalysed by small 1-3 nm sized Ru nanoparticles (NPs) embedded in various imidazolium based ionic liquids (ILs).

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C7GC00513J?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

From the journal:

Green Chemistry

Selective hydrogenation of N-heterocyclic compounds using Ru nanocatalysts in ionic liquids

Abstract

N-Heterocyclic compounds have been tested in the selective hydrogenation catalysed by small 1–3 nm sized Ru nanoparticles (NPs) embedded in various imidazolium based ionic liquids (ILs). Particularly a diol-functionalised IL shows the best performance in the hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline (1THQ) with up to 99% selectivity.

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Selective synthesis of dimethoxyethane via directly catalytic etherification of crude ethylene glycol

Selective synthesis of dimethoxyethane via directly catalytic etherification of crude ethylene glycol

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC00659D, Paper
Weiqiang Yu, Fang Lu, Qianqian Huang, Rui Lu, Shuai Chen, Jie Xu
A potential diesel fuel additive, dimethoxyethane, was highly selectively produced via etherification of crude ethylene glycol over SAPO-34

From the journal:

Green Chemistry

Selective synthesis of dimethoxyethane via directly catalytic etherification of crude ethylene glycol

Abstract

Etherification of ethylene glycol with methanol provides a sustainable route for the production of widely used dimethoxyethane; dimethoxyethane is a green solvent and reagent that is applied in batteries and used as a potential diesel fuel additive. SAPO-34 zeolite was found to be an efficient and highly selective catalyst for this etherification via a continuous flow experiment. It achieved up to 79.4% selectivity for dimethoxyethane with around 96.7% of conversion. The relationship of the catalyst’s structure and the dimethoxyethane selectivity was established via control experiments. The results indicated that the pore structure of SAPO-34 effectively limited the formation of 1,4-dioxane from activated ethylene glycol, enhanced the reaction of the activated methanol with ethylene glycol in priority, and thus resulted in high selectivity for the desired products. The continuous flow technology used in the study could efficiently promote the complete etherification of EG with methanol to maintain high selectivity for dimethoxyethane.

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Iridium-catalyzed highly efficient chemoselective reduction of aldehydes in water using formic acid as the hydrogen source

Iridium-catalyzed highly efficient chemoselective reduction of aldehydes in water using formic acid as the hydrogen source

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC01289F, Paper
Zhanhui Yang, Zhongpeng Zhu, Renshi Luo, Xiang Qiu, Ji-tian Liu, Jing-Kui Yang, Weiping Tang
A highly efficient iridium catalyst is developed for the chemoselective reduction of aldehydes to alcohols in water, using formic acid as a reductant.

Green Chemistry

Iridium-catalyzed highly efficient chemoselective reduction of aldehydes in water using formic acid as the hydrogen source

Abstract

A water-soluble highly efficient iridium catalyst is developed for the chemoselective reduction of aldehydes to alcohols in water. The reduction uses formic acid as the traceless reducing agent and water as a solvent. It can be carried out in air without the need for inert atmosphere protection. The products can be purified by simple extraction without any column chromatography. The catalyst loading can be as low as 0.005 mol% and the turn-over frequency (TOF) is as high as 73 800 mol mol−1 h−1. A wide variety of functional groups, such as electron-rich or deficient (hetero)arenes and alkenes, alkyloxy groups, halogens, phenols, ketones, esters, carboxylic acids, cyano, and nitro groups, are all well tolerated, indicating excellent chemoselectivity.

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C7GC01289F?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Image result for 4-Methoxybenzyl alcohol

4-Methoxybenzyl alcohol (2a)2 . Yellowish oil. Yield: 273 mg, 99%.

1H NMR (400 MHz, CDCl3) δ 7.23 (d, J = 8.8 Hz, 2H), 6.85 (d, J = 8.7 Hz, 2H), 4.52 (s, 2H), 3.76 (s, 3H).

13C NMR (101 MHz, CDCl3) δ 159.07, 133.23, 128.63, 113.89, 64.73, 55.30, 55.26.

Zhanhui Yang

Zhanhui Yang

School of Pharmacy, University of Wisconsin–Madison, Madison, USA
E-mail:weiping.tang@wisc.edu

Organic Chemistry, Green Chemistry, Catalysis

PhD student
Beijing University of Chemical Technology
Organic Chemistry
Beijing, China
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School of Pharmacy, University of Wisconsin–Madison, Madison, USA
Image result for School of Pharmacy, University of Wisconsin–Madison, Madison, USA

Image result for School of Pharmacy, University of Wisconsin–Madison, Madison, USA

Image result for School of Pharmacy, University of Wisconsin–Madison, Madison, USA

4-Methoxybenzyl alcohol

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