From glycerol to chlorohydrin esters using a solvent-free system. Microwave irradiation versus conventional heating

Nanofood Process Technology: Insights on How Sustainability Informs Process Design

Nanostructured products are an actively growing area for food research, but there is little information on the sustainability of processes used to make these products. In this Review, we advocate for selection of sustainable process technologies during initial stages of laboratory-scale developments of nanofoods. We show that selection is assisted by predictive sustainability assessment(s) based on conventional technologies, including exploratory ex ante and "anticipatory" life-cycle assessment. We demonstrate that sustainability assessments for conventional food process technologies can be leveraged to design nanofood process concepts and technologies. We critically review emerging nanostructured food products including encapsulated bioactive molecules and processes used to structure these foods at laboratory, pilot, and industrial scales. We apply a rational method via learning lessons from sustainability of unit operations in conventional food processing and critically apportioned lessons between emerging and conventional approaches. We conclude that this method provides a quantitative means to incorporate sustainability during process design for nanostructured foods. Findings will be of interest and benefit to a range of food researchers, engineers, and manufacturers of process equipment.

Preparation and Uses of Chlorinated Glycerol Derivatives

Crude glycerol (C3H8O3) is a major by-product of biodiesel production from vegetable oils and animal fats. The increased biodiesel production in the last two decades has forced glycerol production up and prices down. However, crude glycerol from biodiesel production is not of adequate purity for industrial uses, including food, cosmetics and pharmaceuticals. The purification process of crude glycerol to reach the quality standards required by industry is expensive and dificult. Novel uses for crude glycerol can reduce the price of biodiesel and make it an economical alternative to diesel. Moreover, novel uses may improve environmental impact, since crude glycerol disposal is expensive and dificult. Glycerol is a versatile molecule with many potential applications in fermentation processes and synthetic chemistry. It serves as a glucose substitute in microbial growth media and as a precursor in the synthesis of a number of commercial intermediates or fine chemicals. Chlorinated derivatives of glycerol are an important class of such chemicals. The main focus of this review is the conversion of glycerol to chlorinated derivatives, such as epichlorohydrin and chlorohydrins, and their further use in the synthesis of additional downstream products. Downstream products include non-cyclic compounds with allyl, nitrile, azide and other functional groups, as well as oxazolidinones and triazoles, which are cyclic compounds derived from ephichlorohydrin and chlorohydrins. The polymers and ionic liquids, which use glycerol as an initial building block, are highlighted, as well.

Chemoenzymatic Solvent-free Synthesis of 1-Monopalmitin Using a Microwave Reactor

An environmentally friendly method for the synthesis of 1-monopalmitin has been developed. The procedure consists of a two-step, solvent-free chemoenzymatic reaction. In the first step, palmitic acid is esterified with solketal (4-hydroxymethyl-2,2-dimethyl-1,3-dioxolane) using Novozym 435 by both conventional heating and microwave irradiation. The use of a microwave reactor allows the enzymatic synthesis of the intermediate compound with a similar yield as that achieved using conventional heating. In the second step, 1,2-acetonide-3-palmitoyl glycerol is cleaved to yield 1-monopalmitin by means of a cation-exchange resin and water or aliphatic alcohols as hydrolytic reagent in solvent-free conditions. The hydrolysis was accomplished in 15 min at 85°C. The best yield was obtained using 1-pentanol. We conclude that the yield achieved depends on the batch and nature of the cation-exchange resin used as catalyst.

From symmetric glycerol derivatives to dissymmetric chlorohydrins

The anticipated worldwide increase in biodiesel production will result in an accumulation of glycerol for which there are insufficient conventional uses. The surplus of this by-product has increased rapidly during the last decade, prompting a search for new glycerol applications. We describe here the synthesis of dissymmetric chlorohydrin esters from symmetric 1,3-dichloro-2-propyl esters obtained from glycerol. We studied the influence of two solvents: 1,4-dioxane and 1-butanol and two bases: sodium carbonate and 1-butylimidazole, on the synthesis of dissymmetric chlorohydrin esters. In addition, we studied the influence of other bases (potassium and lithium carbonates) in the reaction using 1,4-dioxane as the solvent. The highest yield was obtained using 1,4-dioxane and sodium carbonate.