Sorbitan mono-ester

The fatty acid esters of sorbitan (generally referred to as Spans, an Atlcis commercial trade name) and their ethoxylated derivatives (generally referred to as Tweens) are perhaps one of the most commonly used nonionics. The sorbitan esters are produced by reaction of sorbitol with a fatty acid at a high temperature (>200 C). The sorbitol dehydrates to 1,4-sorbitan and then esterification takes place. If one mole of fatty acid is reacted with one mole of sorbitol, one obtains a mono-ester (some di-ester is also produced as a byproduct). Thus, sorbitan mono-ester has the following general formula. 

Polysorbate SO. Sorbltan mono-9-octadecenoate poly(oxy-l,2-ethanediyl) derirs polyoxyethylene (20) sorbi -tan mono -oleate sorethytan (20) mono -oleate polyethylene oxids sorbitan mono-oleate Sorbitan mono-oleate polyoxyethylene Sorlate Tween 80 Monitan Olothorb. An oleate ester of sorbitol and its anhydrides copolymerized with approx 20 moles of ethylene oxide for each mole of sorbitol and sorbitol anhydrides. See also Span. 

Sorbitan mono-9-octadecenoate Sorbitan monooleate Sorbitan monooleic acid ester. See Sorbitan oleate... 

Sorbitan, monooctadecanoate, poly (oxy-1,2-ethanediyl) derive.. See Polysorbate 60 Sorbitan mono-9-octadecenoate Sorbitan monooleate Sorbitan monooleic acid ester. See Sorbitan oleate Sorbitan monopalmitate. See Sorbitan palmitate... 

These very hydrophilic emulsifiers, also called polysorbates, are produced by reacting sorbitan mono fatty acid esters with 5-20 mol of ethylene oxide, and the resulting products are very complex in composition and not very well defined in structure. A possible formula is shown in Table 5.6. 

Esters of fatty acids (w/o) Glycerol monostearate (monosteaiin) Glycerol mono oleate (mraiolem) Sorbitan mono oleate (Span 80) Triglycerol diisostearate... 

The fatty acid sorbitan esters, are often used cyclic polyol esters (w/o). The best known example is sorbitan mono-oleate (Span 80) (Fig. 23.9). 

In the second process step the anhydro sorbitol reacts with a fatty acid at a temperature from about 180 to about 215 °C in the presence of a basic catalyst such as NaOH or K2CO3 in order to produce the desired sorbitan fatty acid ester. Depending on the type and amount of fatty acid used, sorbitan mono, sesqui or tri laurate, palmitate, ole-ate, or stearate are produced. Sorbitan esters have originally been introduced by Atlas Powder Co. (later I Cl, now Croda) under the trademark designation Span . 

The free OH groups in the molecule can be esterified, producing di- and tri-esters. Several products are available depending on the namre of the alkyl group of the acid and whether the product is a mono-, di- or tri-ester. Some examples are sorbitan monolaurate. Span 20 sorbitan monopalmitate, Span 40 sorbitan monostearate. Span 60 sorbitan mono-oleate. Span 80 sorbitan tristearate. Span 65 and sorbitan trioleate. Span 85. 

The ethoxylated derivatives of Spans (Tweens) are produced by reaction of ethylene oxide on any hydroxyl group remaining on the sorbitan ester group. Alternatively, the sorbitol is first ethoxylated and then esterified. However, the final product has different surfactant properties to the Tweens. Some examples of Tween surfactants are polyoxyethylene (20) sorbitan monolaurate. Tween 20 polyoxyethylene (20) sorbitan monopalmitate, Tween 40 polyoxyethylene (20) sorbitan monostearate. Tween 60 polyoxyethylene (20) sorbitan mono-oleate. Tween 80 and polyoxyethylene (20) sorbitan tristearate. Tween 65 and polyoxyethylene (20) sorbitan tri-oleate. Tween 85. 

Anhydrosorbitol Esters. Eatty acid esters of anhydrosorbitol (see Alcohols,polyhydric) are the second largest class of carboxyHc ester surfactants. The important commercial products are the mono-, di-, and triesters of sorbitan and fatty acids (Table 18). Sorbitan is a mixture of anhydrosorbitols, principally 1,4-sorbitan (1) and isosorbide (2) ... 

Typical commercial ethoxylated sorbitan fatty acid esters are yellow Hquids, except tristearates and the 4- and 5-mol ethylene oxide adducts which are light tan soHds. These adducts, as well as the 20-mol adducts of the triesters, are insoluble but dispersible in water. The monoester 20-mol adducts are water soluble. Ethoxylated sorbitan esters are widely used as emulsifiers, antistatic agents, softeners, fiber lubricants, and solubilizers. In combination with the unethoxylated sorbitan esters or with mono- or diglycetides, these are often used as co-emulsrfiers. The ethoxylated sorbitan esters are produced by beating sorbitan esters with ethylene oxide at 130—170°C in the presence of alkaline catalysts. 

A series of sorbitol-based nonionic surfactants are used ia foods as water-ia-oil emulsifiers and defoamers. They are produced by reaction of fatty acids with sorbitol. During reaction, cycHc dehydration as well as esterification (primary hydroxyl group) occurs so that the hydrophilic portion is not only sorbitol but also its mono- and dianhydride. The product known as sorbitan monostearate [1338-41 -6] for example, is a mixture of partial stearic and palmitic acid esters (sorbitan monopalmitate [26266-57-9]) of sorbitol, 1,5-anhydro-D-glucitol [154-58-8] 1,4-sorbitan [27299-12-3] and isosorbide [652-67-5]. Sorbitan esters, such as the foregoing and also sorbitan monolaurate [1338-39-2] and sorbitan monooleate [1338-43-8], can be further modified by reaction with ethylene oxide to produce ethoxylated sorbitan esters, also nonionic detergents FDA approved for food use. 

Low-molecular-weight surfactants ( emulsifiers ) are important ingredients in food products. The types of surfactants most commonly studied in food colloids research are phospholipids (lecithin), mono/diglycerides (particularly glycerol monostearate), polysorbates (Tweens), sorbitan monostearate or monooleate (Spans), and sucrose esters. These small lipid-based amphiphiles can typically lower the interfacial tension to a greater extent than the macromolecular amphiphiles such as proteins and certain gums (Bos and van Vliet, 2001). 

Sorbitan Monostearate occurs as an off white to tan colored, hard, waxy solid. It is a mixture of partial stearic and palmitic acid esters of sorbitol and its mono- and dianhydrides. It is manufactured by reacting edible commercial stearic acid (usually containing associated fatty acids, chiefly palmitic) with sorbitol. It is soluble at temperatures above its melting point in toluene, dioxane, ether, ethanol, methanol, and aniline. It is insoluble in cold water, and in mineral spirits and acetone, but is dispersible in warm water and soluble, with haze, above 50° in mineral oil and in ethyl acetate. 

GLYCOMUL O lONET S-80 LIPOSORB O LIPOSORB 0-20 ML 33F ML 55F MONO-DEHYDROSORBITOL MONOOLEATE MONTAN 80 NIKKOL SO 10 NIKKOL SO-15 NTKKOL SO-30 NONION OP80R O 250 RADIASURI 7155 SORBESTER P 17 SORBITAN MONOOLEIC ACID ESTER SORBITAN O SORBITAN OLEATE SORGEN 40 SPAN 80... 

An emulsion liquid membrane (ELM) system has been studied for the selective separation of metals. This system is a multiple phase emulsion, water-in-oil-in-water (W/O/W) emulsion. In this system, the metal ions in the external water are moved into the internal water phase, as shown in Fig. 3.4. The property of the ELM system is useful to prepare size-controlled aiKl morphology controlled fine particles such as metals, carbonates/ and oxalates.Rare earth oxalate particles have been prepared using this system, consisting of Span83 (sorbitan sesquioleate) as a surfactant and EHPNA (2-ethyl-hexylphospholic acid mono-2-ethylhexyl ester) as an extractant. In the case of cerium, well-defined and spherical oxalate particles, 20 - 60 nm in size, are obtained. The control of the particle size is feasible by the control of the feed rare earth metal concentration and the size of the internal droplets. Formation of ceria particles are attained by calcination of the oxalate particles at 1073 K, though it brings about some construction of the particles probably caused by carbon dioxide elimination. 

Sorbitan monolaurate (sorbitan, esters mono-decanoate)... 

Sorbitan monoesters are a series of mixtures of partial esters of sorbitol and its mono- and dianhydrides with fatty acids. Sorbitan diesters are a series of mixtures of partial esters of sorbitol and its monoanhydride with fatty acids. 

Glycerides, glucosides, saccharides, sorbitan derivatives, Tweens and Spans, etc. also belong to the class of nonionic surfactants. Mono- and diesters of fatty acids and multiatomic alcohols are oil soluble surfactants with low solubility in water. Sulfoesterification of these compounds followed by subsequent neutralization allows one to obtain water soluble surfactants. Many representatives of this group, such as sucrose esters, are non-toxic, tasteless and odorless, which makes them attractive for use in the pharmaceutical, food and perfume industries. 

Monocresyl diphenyl phosphate. See Diphenylcresyl phosphate Monodehychosorbitol monooleate. See Sorbitan oleate Mono- arid diglycerides, acetic acid esters. SeeAcetylated mono- and diglycerides of fatly ackfs... 

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