Surfactants Imidazolines

Aminoethyl Tall Oil Imidazoline Dark Amber, Viscous Liquid Concentration, % 100 

Soluble in mineral oil, vegetable and animal glycerides and most organic solvents. Forms hazy, stable dispersion in water which can be clarified by acidifying with mineral or organic acids. Excellent emulsifier for mineral, vegetable and animal oils. Formulations containing 1-4% T-44 exhibit excellent emulsion stability. Corrosion inhibitor in its basic form or as its salts. 

Hydroxyethyl Coco Imidazoline Light Tan Paste Concentration, % 100 

---

Amphoteric Detergents. These surfactants, also known as ampholytics, have both cationic and anionic charged groups ki thek composition. The cationic groups are usually amino or quaternary forms while the anionic sites consist of carboxylates, sulfates, or sulfonates. Amphoterics have compatibihty with anionics, nonionics, and cationics. The pH of the surfactant solution determines the charge exhibited by the amphoteric under alkaline conditions it behaves anionically while ki an acidic condition it has a cationic behavior. Most amphoterics are derivatives of imidazoline or betaine. Sodium lauroamphoacetate [68647-44-9] has been recommended for use ki non-eye stinging shampoos (12). Combkiations of amphoterics with cationics have provided the basis for conditioning shampoos (13). 

Baby Shampoos. These shampoos, specifically marketed for small children, feature a non-eye stinging quaHty. The majority of the products in this category are based on an amphoteric detergent system a system combining the use of an imidazoline amphoteric with an ethoxylated nonionic surfactant has been successfiiUy marketed (15,16). The sulfosuccinates also have been suggested for baby shampoo preparation because of thek mildness... 

Oil field uses are primarily imidazolines for surfactant and corrosion inhibition (see Petroleum). Besides the lubrication market for metal salts, the miscellaneous market is comprised of free acids used ia concrete additives, motor oil lubricants, and asphalt-paving applications (47) (see Asphalt Lubrication AND lubricants). Naphthenic acid has also been studied ia ore flotation for recovery of rare-earth metals (48) (see Flotation Lanthanides). 

In addition to the mono- and dialkylamines, representative stmctures of this class of surfactants include /V-alkyltrimethylene diamine, RNH(CH2)3NH2, where the alkyl group is derived from coconut, tallow, and soybean oils or is 9-octadecenyl, 2-aLkyl-2-imidazoline (3), where R is heptadecyl, heptadecenyl, or mixed alkyl, and l-(2-aniinoethyl)-2-aLk5l-2-imidazoline (4), where R is heptadecyl, 8-heptadecenyl, or mixed alkyl. 

Fabric Softeners, Surfactants and Bleach Activators. Mono- and bisamidoamines and their imidazoline counterparts are formed by the condensation reaction of one or two moles of a monobasic fatty acid (typically stearic or oleic) or their methyl esters with one mole of a polyamine. Imidazoline formation requires that the ethyleneamine have at least one segment in which a secondary amine group Hes adjacent to a primary amine group. These amidoamines and imidazolines form the basis for a wide range of fabric softeners, surfactants, and emulsifiers. Commonly used amines are DETA, TETA, and DMAPA, although most of the polyethylene and polypropane polyamines can be used. 

Many of the surfactants made from ethyleneamines contain the imidazoline stmcture or are prepared through an imidazoline intermediate. Various 2-alkyl-imidazolines and their salts prepared mainly from EDA or monoethoxylated EDA are reported to have good foaming properties (292—295). Ethyleneamine-based imida zolines are also important intermediates for surfactants used in shampoos by virtue of their mildness and good foaming characteristics. 2- Alkyl imidazolines made from DETA or monoethoxylated EDA and fatty acids or their methyl esters are the principal commercial intermediates (296—298). They are converted into shampoo surfactants commonly by reaction with one or two moles of sodium chloroacetate to yield amphoteric surfactants (299—301). The ease with which the imidazoline intermediates are hydrolyzed leads to arnidoamine-type stmctures when these derivatives are prepared under aqueous alkaline conditions. However, reaction of the imidazoline under anhydrous conditions with acryflc acid [79-10-7] to make salt-free, amphoteric products, leaves the imidazoline stmcture essentially intact. Certain polyamine derivatives also function as water-in-oil or od-in-water emulsifiers. These include the products of a reaction between DETA, TETA, or TEPA and fatty acids (302) or oxidized hydrocarbon wax (303). The amidoamine made from lauric acid [143-07-7] and DETA mono- and bis(2-ethylhexyl) phosphate is a very effective water-in-od emulsifier (304). 

Both anodic and general inhibitors are nonpassivating and are suitable for use with hydrochloric acid-based cleaners. Other inhibitor groups include filming amines such as polymethylimine and diamines, the rosin-amine ketones, and also some of the imidazoline surfactants. The imidazolines provide increased protection at levels up to their critical miscelle concentration (CMC), above which there is a leveling off as a thick, adherent diffusion barrier is formed. 

The foam-holding characteristics of foam from surfactants in oil field jobs can be tailored by adding an imidazoline-based amphoacetate surfactant. Amphoacetates are a special class of amphoteric tensides (Figure 16-1). Imidazoles, such as 2-heptylimidazoline, are reacted with fatty acids under the ring opening. For alkylation, the imidazoline is reacted with, for example, chloroacetate [493]. 

D. J. Dino and A. Homack. Use of high purity imidazoline based amphoacetate surfactant as foaming agent in oil wells. Patent US 5614473, 1997. 

The only cationic surfactant (Fig. 23) found in any quantity in the environment is ditallow dimethylammonium chloride (DTDMAC), which is mainly the quaternary ammonium salt distearyldimethylammonium chloride (DSDMAC). The organic chemistry and characterization of cationic surfactants has been reported and reviewed [330 - 332 ]. The different types of cationic surfactants are fatty acid amides [333], amidoamine [334], imidazoline [335], petroleum feed stock derived surfactants [336], nitrile-derived surfactants [337], aromatic and cyclic surfactants [338], non-nitrogen containing compounds [339], polymeric cationic surfactants [340], and amine oxides [341]. 

One type of cationic surfactant was the fatty acid derivatives of polyamines. The properties of the derivatives of fatty acids and ethylenediamine have been described in the literature (7-9). It appeared from these reports that the 2-alkyl-2-imidazolines would not impart sufficient hydrophobicity to soils. However, the analogous series of homologous compounds from the fatty acids and diethylene-triamine (BETA) appeared likely to do so because of their higher molecular weight. 

Compositions and functions of typical commercial products in the 2-alkyl-l-(2-hydroxyethyl)-2-imidazolines series are given in Table 29. 2-Alkyl-l-(2-hydroxyethyl)-2-imidazolines are used in hydrocarbon and aqueous systems as antistatic agents, corrosion inhibitors, detergents, emulsifiers, softeners, and viscosity builders. They are prepared by heating the salt of a carboxylic acid with (2-hydroxyethyl)ethylenediamine at 150—160°C to form a substituted amide 1 mol water is eliminated to form the substituted imidazoline with further heating at 180—200°C. Substituted imidazolines yield three series of cationic surfactants by ethoxylation to form more hydrophilic products quatemization with benzyl chloride, dimethyl sulfate, and other alkyl halides and oxidation with hydrogen peroxide to amine oxides. 

Industrial surfactants find uses in almost every industry, from asphalt manufacturing to carpet fibers, from pulp and paper production to leather processing. Examples of the types of chemicals used as surfactants are fatty alcohol sulfates, alkanolamides, alkoxylates, sulfosuccinates, amines, quaternaries, phosphate esters, acid esters, blockcopolymers, betaines, imidazolines, alkyl sulfonates, etc. 

Commercially important surfactants based on heterocyclic structures are relatively few in number (B-80MI11510) the most important are the cationic compounds derived from imidazoline (48). Cetyl pyridinium halides (49) are used as germicides and sanitizing agents. Piperidinium (50) and morpholinium (51) compounds find application in hair conditioning formulations as antistatic agents. Substituted oxazolines (52) are a class of cationic dispersants and corrosion inhibitors. 

Nitrogen cationic surfactants can also be created by the use of difunctional small molecule amines which, after formation of an amide or ester bond, leave an amine residue which is suitable for quaternization as shown in eqs 6.1.9-6.1.11. The amine residue is then reacted with a suitable alkylating agent to form the cationic. Similarly, reaction of a triglyceride with diethylene triamine gives initially the diamide which, under appropriate conditions, can be cyclized to imidazoline [16] ... 

Two major classes of amphoteric surfactants are derived from fatty alkyl hydroxyethyl imidazolines which, in turn, are produced from fatty acids and low molecular weight amines. Because fatty acids are fairly economic, the imidazoline derived amphoacetates tend to be less expensive than the iminodipropionates discussed above. Most imidazoline derived... 

These imidazoline compounds have proved very useful as intermediates to amphoteric surfactants. Products made from them, alkylated with sodium chloroacetate or methyl acrylate were patented by Hans Mannheimer who founded Miranol Company in the USA during the 1950s [2]. Miranol Company became the major vendor of imidazoline derived amphoteric surfactants in the world. Other imidazolines are used to produce amphoteric surfactants, such as alkyl aminoethyl imidazoline, but those products are of less economic significance. 

As mentioned above, most commercial products are based on either a lauric (mainly C-12) or a whole coconut distribution (C-8 to C-18, with approximately 50% C-12) since these alkyl distributions give the best detergency. Early on, the imidazoline derived amphoterics were characterized as exceptionally mild to the skin and eyes relative to most surfactants available at the time. This made them excellent candidates for use in baby shampoos, geriatric cleansing products, hand wash for medical facilities and so on. 

The other major class of fatty imidazoline derived amphoteric surfactants is the amphopropionates. Again, the ampho portion of the name indicates that they are derived from imidazolines but, rather than being alkylated with sodium chloroacetate, they are carboxy-lated with an acrylate via the Michael reaction. A primary or secondary amine is added across the double bond of the acrylate to yield the beta-alanine derivative. 

Miranol Company introduced a series of these surfactants based on the condensation of alkyl hydroxyethyl imidazolines with methyl acrylate [5]. Similar to the amphoacetates above, the assumption was made that the first mole of methyl acrylate quaternized the imidazoline ring and the second added to the hydroxyethyl group to produce an ether carboxylate (see Figure 6.12). 

Most of the amphopropionate surfactants produced are of the amphodipropionate type, 2 mol of methyl acrylate or sodium acrylate added per mole of imidazoline. Depending on the reaction conditions, 1 mol of acrylate can add to the fatty R group at the alpha carbon. Upon hydrolysis of the imidazoline, the second reacts with the liberated secondary amine to produce the beta alanine derivative. If methyl acrylate is used, the methyl ester of the amphoteric surfactant is formed. An equimolar amount of sodium hydroxide is added to effect saponification to the sodium salt of the surfactant. Methanol is formed as a by-product and it is generally left in the final product as part of the solvent system. 

Mona Industries received a series of patents in the 1980s for betaines and imidazoline-based surfactants similar to the hydroxysultaines and hydroxypropylsulfonates discussed earlier but alkylated with a propanechlorohydrin phosphate rather than the CHPS [9]. These amphoteric surfactants were demonstrably mild and were thought to have some... 

A saturated bromine aqueous solution can also be used to determine the type of amphoteric surfactant. Add 5 ml of 1 % sample solution to 1.5 ml saturated bromine aqueous solution. Observe the colour of the precipitate. Heat the mixture and observe the change in the precipitate. If the precipitate is a yellow to yellow-orange colour and is dissolved to form a yellow solution after heating, the sample is an imidazoline or alanine type of amphoteric surfactant. If the precipitate is a white to yellow colour and insoluble after heating, the sample is the other type of amphoteric surfactant. 

---