Carbohydrate‐alkyl ester derivatives as biosurfactants

Abstract

Reaction of carbohydrates with long-chain plantderived lipids yields carbohydrate-alkyl ester surfactants with a polyol structure. Their renewability, low cost, and environmental acceptability make carbohydrate-alkyl ester surfactants an excellent alternative to petrochemically derived products. This article reviews developments in the synthesis and surface-active properties of carbohydrate-alkyl ester surfactants.Paper no. S1150 in JSD 2, 383-390 (July 1999). KEY WORDS:Biosurfactants, carbohydrate esters, sugar esters.Surfactants are critical to the cleaning, emulsifying, wetting, and foaming properties of many products. Surfactants are found in a host of applications, including cosmetics, textiles, pharmaceuticals, foods, ore flotation, soaps and detergents, pulp and paper manufacturing, lubricating and metalworking, agrichemicals, and petroleum mining fields. In most industrial cases, surfactants are used as processing aids and are disposed of following usage. Issues regarding disposal have created interest in more biologically acceptable alternatives and more focused use of renewable vs. nonrenewable resources.In this context, carbohydrate-based surfactants are gaining attention. Carbohydrates in the form of polysaccharides are produced naturally in plants and account for approximately three-quarters of the dry weight of the biological world and nearly 80% of the human caloric diet (1). Corn, potatoes, tapioca, and wheat are currently processed and constitute common sources of starch. Polysaccharides are of interest because of the number of reactive hydroxyl groups they carry. Condensation of one of the reactive groups of a saccharide with a fatty acid produces a surfactant. The saccharide provides the hydrophilic component, whereas the fatty acid provides the hydrophobic component. Various types of saccharides that have been used to furnish the required hydrophilicity are outlined in Scheme 1. Carbohydrate-based surfactants have been used primarily in the cosmetic, detergent, food, and pharmaceutical industries (2-4) as they are physiologically, dermatologically, and biologically acceptable (5,6). Because they are odorless, tasteless, nonionic, and biodegradable, they compare well in overall performance (i.e., emulsification, detergency, foam power, wetting power, and other related properties) with other surface-active compounds (7).To date, several major types of carbohydrate-based surfactants are used worldwide. Sucrose esters and sorbitan esters as well as other carbohydrate derivatives are highlighted here. SUCROSE ESTERSSucrose esters are synthesized primarily by combining the primary hydroxyl group of the nonreducing glucose moiety with a methyl ester of a fatty acid (Scheme 2). Synthesis of sucrose fatty acid derivatives was first considered by Herzfeld in 1880 (5). Sucrose octaesters were later synthesized and their physical properties measured (8,9). In 1924, a patent disclosing the condensation of fatty acid chlorides with sucrose in pyridine was awarded to Rosenthal (5), and in 1950 Zief (10) desc...

Surface and Self‐Aggregation Properties of Bis‐Benzimidazolones Derivatives of d‐Glucose

“…as emulsifiers, solubilizing agents for proteins [6] and vehicles for drugs [7]. Consequently, their synthesis and physicochemical properties have been the subject of numerous studies [8][9][10][11][12][13][14][15], resulting in some interesting findings. Sugar-derived surfactants form aggregates which, in the presence of additives, can grow into very long worm-like micelles [16].…”

Synthesis and characterization of maltose fatty acid monoesters as biosurfactants

“…Because they are odorless, tasteless, nonionic, and biodegradable, they compare well in overall performance (i.e., emulsification, detergency, foam power, wettability, and other related properties) with other surface-active compounds (4). To date, several major types of carbohydratebased surfactants are commonly used worldwide, including sorbitan esters, sucrose esters, alkyl glycosides, and glucoseamide derivatives (5)(6)(7)(8).…”

Synthesis of new extended surfactants containing a xylitol polar group

“…The product (8), eluted with hexane/acetone (85:15 vol/vol) over a silica-gel column, was obtained pure as a viscous liquid (32.5 g, 76% yield). 1 (9). Compound 8 (10.6 g, 12 mmol) was dissolved in 96% ethanol (42 mL) and treated with 15 H + Amberlyst resin (8 mL), and the mixture was stirred at 60°C for 11 h. The solvent was then evaporated under reduced pressure.…”