CUED Publications database

Direct valorisation of waste cocoa butter triglycerides via catalytic epoxidation, ring-opening and polymerisation

Plaza, DD and Strobel, V and Heer, PKK and Sellars, AB and Hoong, SS and Clark, AJ and Lapkin, AA (2017) Direct valorisation of waste cocoa butter triglycerides via catalytic epoxidation, ring-opening and polymerisation. Journal of Chemical Technology and Biotechnology.

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BACKGROUND: Development of circular economy requires significant advances in the technologies for valorisation of waste, as waste becomes new feedstock. Food waste is a particularly important feedstock, containing large variation of complex chemical functionality. Although most food waste sources are complex mixtures, waste from food processing, no longer suitable for the human food chain, may also represent relatively clean materials. One such material requiring valorisation is cocoa butter. RESULTS: Epoxidation of a triglyceride from a food waste source, processing waste cocoa butter, into the corresponding triglyceride epoxide was carried out using a modified Ishii-Venturello catalyst in batch and continuous flow reactors. The batch reactor achieved higher yields due to the significant decomposition of hydrogen peroxide in the laminar flow tubular reactor. Integral and differential models describing the reaction and the phase transfer kinetics were developed for the epoxidation of cocoa butter and the model parameters were estimated. Ring-opening of the epoxidised cocoa butter was undertaken to provide polyols of varying molecular weight (M$_\text{w}$ = 2000-84 000 Da), hydroxyl value (27-60 mg KOH g$^{-1}$) and acid value (1-173 mg KOH g$^{-1}$), using either aqueous ortho-phosphoric acid (H$_3$PO$_4$) or boron trifluoride diethyl etherate (BF$_3$·OEt$_2$)-mediated oligomerisation in bulk, using hexane or tetrahydrofuran (THF) as solvents. The thermal and tensile properties of the polyurethanes obtained from the reaction of these polyols with 4,4'-methylene diphenyl diisocyanate (MDI) are described. CONCLUSION: The paper presents a complete valorisation scheme for a food manufacturing industry waste stream, starting from the initial chemical transformation, developing a process model for the design of a scaled-up process, and leading to synthesis of the final product, in this case a polymer. This work describes aspects of optimisation of the conversion route, focusing on clean synthesis and also demonstrates the interdisciplinary nature of the development projects, requiring input from different areas of chemistry, process modelling and process design.

Item Type: Article
Uncontrolled Keywords: cocoa butter epoxidation flow chemistry food waste phase-transfer catalysis polyurethane renewable feedstocks ring-opening polymerisation
Divisions: Div E > Manufacturing Systems
Div B > Electronics, Power & Energy Conversion
Depositing User: Cron Job
Date Deposited: 22 Jan 2018 20:12
Last Modified: 20 Sep 2018 02:16