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Lipase-Mediated Syntheses of Trimethylolpropane-Based Biolubricant and Cyclic Carbonate

Bornadel, Amin LU (2013)
Abstract (Swedish)
Popular Abstract in English

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Since the beginning of mankind, humans have managed to find ways to make use of the resources available at hand in order to survive and even to improve their livelihoods. The basic needs for food as well as other amenities were met from plant- and animal resources until the 19th century when industrial revolution changed the base of production to fossil sources. Access to coal initially followed by mineral oil and natural gas accompanied by ingenious chemistry and process development has provided us with unlimited number of products that are present in everything we use today. It has changed the way we live to an extent that it is difficult to think of a life without... (More)
Popular Abstract in English

Popular Summary

Since the beginning of mankind, humans have managed to find ways to make use of the resources available at hand in order to survive and even to improve their livelihoods. The basic needs for food as well as other amenities were met from plant- and animal resources until the 19th century when industrial revolution changed the base of production to fossil sources. Access to coal initially followed by mineral oil and natural gas accompanied by ingenious chemistry and process development has provided us with unlimited number of products that are present in everything we use today. It has changed the way we live to an extent that it is difficult to think of a life without these products.

All the development has of course come at a cost - to the environment and health, the effects of which have started to be felt in terms of increased greenhouse gas emissions, toxic discharges to wastewaters, oceans, persistent pollutants in soil and ground water, climate change, etc. Moreover, the fossil reserves that have taken millions of years to build up, are depleting rapidly. This has led to an increased awareness and demand for alternative renewable resources, toxic-free, environment-friendly production process and nontoxic, biodegradable products. This has provided an interesting challenge to the scientists and engineers to consider the possibilities of developing new or improved products that fulfill the market demand and innovative technologies for processing a different raw material and not posing an environmental burden. Among the several alternatives, industrial biotechnology using microorganisms and their enzymes has gained increased attention for production of chemicals, materials and energy.

The studies in this thesis are targeting two product groups that reflect many of the problems stated above - lubricants and polymers (polyurethanes and polycarbonates). Lubricants are used in all mechanical equipment to reduce friction and wear and for other applications. Historically - from the time the Egyptians built pyramids - lubricants were made of vegetable oils and fats, but the modern lubricants are based on mineral oil. Spillage of the lubricants has resulted in widespread environmental problem. For the vegetable oils to work as well as the mineral oil based lubricants, they need to be modified so that the resulting product can be used without problems at very low and very high temperatures. This is possible by reacting fatty acid component of the oil with a branched molecule to give a biolubricant product that is still flowing at sub-zero temperature and is stable above in hot environments.

Polyurethanes and polycarbonates are materials with a market of several Mtonnes. They are used for making many products like coatings, foams, adhesives, transparent plastics, etc. The problem however is the use of phosgene, a toxic gas or isocyanate, a product of phosgene, in their manufacture. Even the products may have some traces of the components left in them. Thus, a phosgene/isocyanate-free route for producing these materials would be extremely attractive. One route is to use cyclic carbonates as building blocks that is discussed in this thesis.

The thesis presents the use of lipase, an enzyme that breaks down fats and oils in nature, for synthesis of biolubricants and cyclic carbonates. The processes developed do not make use of any volatile organic solvents and are run under very mild conditions compared to the chemical processes. It is shown that different approaches can be used to improve the process efficiency and to get high product yields. (Less)
Abstract
Abstract

Biocatalysis is considered as benign and efficient alternative to chemical catalysis for organic syntheses. Lipases are the most versatile biological catalysts implemented so far with great potential for production of different chemicals and materials in non-conventional reaction media. This thesis presents investigations on lipase catalyzed esterification and transesterification reactions in solvent-free media with a polyol (tri-ol), trimethylolpropane (TMP) to form TMP-trioleate and -cyclic carbonate for lubricant and polymer applications, respectively.

Conventional lubricants are mineral oil based and lack biodegradability resulting in their accumulation in the environment. Synthetic esters of polyhydric... (More)
Abstract

Biocatalysis is considered as benign and efficient alternative to chemical catalysis for organic syntheses. Lipases are the most versatile biological catalysts implemented so far with great potential for production of different chemicals and materials in non-conventional reaction media. This thesis presents investigations on lipase catalyzed esterification and transesterification reactions in solvent-free media with a polyol (tri-ol), trimethylolpropane (TMP) to form TMP-trioleate and -cyclic carbonate for lubricant and polymer applications, respectively.

Conventional lubricants are mineral oil based and lack biodegradability resulting in their accumulation in the environment. Synthetic esters of polyhydric alcohols and fatty acids are biodegradable and possess desirable technical properties for lubricant applications. Synthesis of TMP-trioleate from oleic acid and TMP catalyzed by commercial immobilized Candida antarctica lipase B, Novozym®435 (N435) was studied by varying reaction parameters. The product obtained possesses desirable pour point (-42 °C) for lubricant applications in sub-zero conditions. The biocatalyst was recycled in reactions at 70 °C for 7 batches, 24 h each, with a half-life of 94 h. The biocatalyst half-life was doubled by washing it with 2-propanol between the batches. A simplified kinetic model was developed for the lipase-catalyzed reaction in order to facilitate optimization and design of the process and minimize the amount of resources required for investigations of the process. The methodology used for the kinetic modeling is applicable for similar types of enzymatic reactions involving multi-substrate multi-product systems.

Cyclic carbonates are potential monomers for phosgene-/isocyanate-free polycarbonates and polyurethanes that have wide range of applications. Six-membered cyclic carbonates can readily undergo ring-opening polymerization to form aliphatic polycarbonates and polyurethanes and their copolymers. Six-membered cyclic carbonate with hydroxyl functional group was obtained with 75% yield using a chemoenzymatic process involving lipase B catalyzed transesterification of dimethylcarbonate (DMC) with TMP in the presence of molecular sieve to form linear TMP carbonate followed by thermal cyclization. Performing the reaction in a recirculating flow reactor, higher conversion rates were obtained compared to the batch process, the product was recovered easily without extra separation steps, and the biocatalyst and molecular sieve remained intact for reuse. In silico evaluations of the reaction accompanied with empirical investigations confirmed that lipase B prefers DMC as acyl-donor while TMP and its derivatives, formed during the course of the reaction, serve as acyl acceptors. The formation of TMP carbonate oligomers hence found to be non-enzymatic and intensified by heat. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Hanefeld, Ulf, Department of Biotechnology, Delft University of Technology, Delft, The Netherlands
organization
publishing date
type
Thesis
publication status
published
subject
defense location
Lecture Hall C, Centre for Chemistry and Chemical Engineering, Sölvegatan 39, Lund University, Faculty of Engineering
defense date
2013-10-11 10:15
ISBN
978-91-89627-95-6
language
English
LU publication?
yes
id
36c061d2-07bf-4a38-9970-299a83a0c31c (old id 4025182)
date added to LUP
2013-09-17 08:57:03
date last changed
2016-09-19 08:45:17
@phdthesis{36c061d2-07bf-4a38-9970-299a83a0c31c,
  abstract     = {Abstract<br/><br>
Biocatalysis is considered as benign and efficient alternative to chemical catalysis for organic syntheses. Lipases are the most versatile biological catalysts implemented so far with great potential for production of different chemicals and materials in non-conventional reaction media. This thesis presents investigations on lipase catalyzed esterification and transesterification reactions in solvent-free media with a polyol (tri-ol), trimethylolpropane (TMP) to form TMP-trioleate and -cyclic carbonate for lubricant and polymer applications, respectively.<br/><br>
Conventional lubricants are mineral oil based and lack biodegradability resulting in their accumulation in the environment. Synthetic esters of polyhydric alcohols and fatty acids are biodegradable and possess desirable technical properties for lubricant applications. Synthesis of TMP-trioleate from oleic acid and TMP catalyzed by commercial immobilized Candida antarctica lipase B, Novozym®435 (N435) was studied by varying reaction parameters. The product obtained possesses desirable pour point (-42 °C) for lubricant applications in sub-zero conditions. The biocatalyst was recycled in reactions at 70 °C for 7 batches, 24 h each, with a half-life of 94 h. The biocatalyst half-life was doubled by washing it with 2-propanol between the batches. A simplified kinetic model was developed for the lipase-catalyzed reaction in order to facilitate optimization and design of the process and minimize the amount of resources required for investigations of the process. The methodology used for the kinetic modeling is applicable for similar types of enzymatic reactions involving multi-substrate multi-product systems.<br/><br>
Cyclic carbonates are potential monomers for phosgene-/isocyanate-free polycarbonates and polyurethanes that have wide range of applications. Six-membered cyclic carbonates can readily undergo ring-opening polymerization to form aliphatic polycarbonates and polyurethanes and their copolymers. Six-membered cyclic carbonate with hydroxyl functional group was obtained with 75% yield using a chemoenzymatic process involving lipase B catalyzed transesterification of dimethylcarbonate (DMC) with TMP in the presence of molecular sieve to form linear TMP carbonate followed by thermal cyclization. Performing the reaction in a recirculating flow reactor, higher conversion rates were obtained compared to the batch process, the product was recovered easily without extra separation steps, and the biocatalyst and molecular sieve remained intact for reuse. In silico evaluations of the reaction accompanied with empirical investigations confirmed that lipase B prefers DMC as acyl-donor while TMP and its derivatives, formed during the course of the reaction, serve as acyl acceptors. The formation of TMP carbonate oligomers hence found to be non-enzymatic and intensified by heat.},
  author       = {Bornadel, Amin},
  isbn         = {978-91-89627-95-6},
  language     = {eng},
  school       = {Lund University},
  title        = {Lipase-Mediated Syntheses of Trimethylolpropane-Based Biolubricant and Cyclic Carbonate},
  year         = {2013},
}