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Tuesday 3 January 2017

Greener benzaldehyde for sustainable future

In an interview, Dr Anjali Patel, a professor at the Department of Chemistry’s Polyoxometalates and Catalysis Laboratory, Faculty of Science, The Maharaja Sayajirao University (MSU) of Baroda, India with Chemical Today magazine opens up about her path-breaking research on manufacturing environment friendly benzaldehyde with promising ways of enhancing magnitude of industrial applications.
She has bagged two Indian patents for use of solid catalyst in the manufacturing of benzaldehyde and cycloaliphatic epoxide.
Elaborate on your research.
Benzaldehyde is a simplest aromatic aldehyde and is very industrially useful with widespread applications in perfumery, dyestuff and agrochemical industries. It is the second most important aromatic molecule (after vanillin) used in the cosmetics and flavour industries. Synthetic benzaldehyde is the flavouring agent in imitation almond extract, which is used to flavour cakes and other baked goods.
The general procedure of synthesis of benzaldehyde involves oxidation of styrene, benzyl alcohol, and toluene as well as hydrolysis of benzyl chloride. Traditionally oxidation of toluene is usually carried out in organic solvents which are environmentally undesirable and benzaldehyde is produced from hydrolysis of benzyl chloride often containing traces of chlorine impurities and copious/toxic waste is generated in this process. These procedures suffer from a lack of selectivity, use of organic solvents, the toxicity of the reagents and waste production.
The technology addresses few issues in benzaldehyde manufacturing.
The present invention provides an improved process for the liquid phase oxidation of styrene under mild conditions with cheapest environmental oxidant O2 using a Ruthenium-based solid catalyst.
The present patent provides oxidation of styrene with 100 percent conversion and >99 percent selectivity for benzaldehyde without any use of phase transfer catalysts.
The advantage of the process lies in the simple oxidation process under solvent free atmosphere as well as at lower temperature and relatively short time.
Further, the catalysts can be regenerated and reused. The most important advantage of the present invention is no formation of any by-product. As the invention satisfies some of the principles of green chemistry such as solvent free reactions, mild conditions, easy product separation, recovery and recyclability, higher catalytic activity and selectivity, no waste and use of green oxidant ie. O2. The present technology is energy efficient preferably eliminates the formation of waste, avoids the use of toxic solvents and reagents. Thus, by combining green chemistry and solid catalysts, sustainability was achieved.
Industrial demand for this technology.
Based on the synthesis, analysis and interpretation of available information about the global benzaldehyde market, major contributors for the same are: Hubei GreenHome, Wuhan Youji, Wuhan Biet, Jiangyin STM, Wuhan Youji, Hongrun, Jiangyin Hongtai (China); Emerald Kalama Chemical (USA); Daurala Organics (India); Lanxess (Germany); and Polynt (Italy). Thus, looking to the supply/demand for benzaldehyde, there are a number of opportunities/challenges for industries, it is a need for existing companies as well as new entrants to capitalise the opportunities and to develop business strategies.
According to Transparency Market Research report, the global market for benzaldehyde was valued as $234.4 million in 2014 and it is anticipated to reach $318 million by 2023, at a CAGR of 3.4 percent between 2015 and 2023.
In terms of demand, Asia-Pacific held the largest share of over 50 percent of the benzaldehyde market. Due to increased demand for benzaldehyde, in industries such as aroma chemicals, pharmaceuticals and agriculture, countries such as India and China will tend to drive the benzaldehyde market in the near future.
This will also help develop the economic growth in the region. Thus, high growth potential in developing countries and rising use of benzaldehyde is projected to provide opportunities for the market during this period.
Other research work.
My current research interests cover Material Science, Polyoxometalates, Heterogeneous Catalysis and Green Chemistry. I am leading a research group focusing on tailoring of new catalytic materials based on polyoxometalates/heteropolyacids, lacunary as well as Transition metal substituted polyoxometalates and their applications for organic transformations, such as esterification, alkylation, acylation, hydrogenation, oxidation, C–C coupling and bio-diesel production.
Presently, we are concentrating on bio-diesel production using supported polyoxometalates-based solid acid catalysts. Biodiesel finds applications as fuel for domestic vehicular use, railways as well as in aircrafts in many countries. In 2007, McDonald's of UK announced that it would start producing biodiesel from the waste oil by-product of its restaurants. This fuel would be used to run its fleet.
The British train operating company Virgin Trains claimed to have run the UK’s first “biodiesel train”, which was converted to run on 80 percent petroleum-based diesel and 20 percent biodiesel. Also in 2007, Disneyland began running the park trains on B98 (98 percent biodiesel). The program was discontinued in 2008 due to storage issues, but in January 2009, it was announced that the park would then be running all trains on biodiesel manufactured from its own used cooking oils. This is a change from running the trains on soy-based biodiesel.
On 7 November 2011 United Airlines flew the world’s first commercial aviation flight on a microbially derived biofuel using Solajet, Solazyme’s algae-derived renewable jet fuel. This shows the progress in applications of biodiesel worldwide.
We have already succeeded for low-cost biodiesel production by utilisation of low-quality raw materials as feedstocks such as waste cooking oil obtained from canteens, restaurants and from houses which are reach in fatty acids. We have also proposed an industrial process for low-cost biodiesel production and looking for the opportunities to transfer the technology.
Plan to commercialise the innovative technology.
The present patent has great opportunities at international level as it is totally green and also economically viable. Looking at the scenario, in the future, I would like to apply for a US patent. I am sure our invention will contribute towards the already mentioned sectors and related chemical sectors will be benefitted, environmentally as well as economically. At present, I am into talks with few chemical industries of my region (Vadodara-based) for the possibility of commercialisation and I hope that it will be done in the near future.
The second patent is about selective aerobic epoxidation of cycloalkenes using a Polyoxometalate-based solid catalyst. Cyclohexene oxide is a cycloaliphatic epoxide. It is a useful monomer in polymerization and coating industry, especially in thermoplastic synthesis.
It is used in the synthesis of alicyclic target materials including pesticides, pharmaceuticals, perfumery and dyestuffs. Many traditional processes result in the formation of nitrous oxide, a greenhouse gas that has to be decomposed. These disadvantages have to be addressed by using solid catalysts. The patent also provides an improved process for the aerobic epoxidation of Cis-cyclohexene in solvent-free liquid phase. Thus, the present invention provides oxidation process achieving 85 percent conversion of Ciscyclohexene with 100 percent selectivity towards Cis-cyclohexene oxide.
Message for young researchers.
The whole journey (patent filing 2010 and granted in 2016) from carrying out an experiment to writing as well as the filing of the patent as well as giving inputs to reviewer’s time-to-time was very exciting and difficult as well. But at the same time, I learnt a lot of things. It was really a great experience in doing the research at the university and acquiring the patents!
My message to young researchers’ is that place does not matter! If you work hard with 100 percent dedication, you will achieve success. However, every so often it takes more time than expected.
© Chemical Today Magazine
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