Ethanolamines

Mono- and triethanolamine are miscible with water or alcohol in all proportions and is only slightly soluble in ether. Diethanolamine will dissolve in water, is very soluble in alcohol, and is only slightly soluble in ether. All of the compounds are clear, viscous liquids at standard conditions and white crystalline solids when frozen. They have a relatively low toxicity. In early processes, the ethanolamines were manufactured by reacting ethylene chlorohydrin (C1CH2CH20H) with ammonia (NH3). Current processes 

Higher ammonia-ethylene oxide ratios favor high yields of diethanolamine and triethanolamine, whereas lower ratios are used where maximum production of monoethanolamine is desired. The reaction is noncatalytic. The pressure is moderate, just sufficient to prevent vaporization of components in the reactor. The bulk of the water produced in the reaction is removed by subsequent evaporation. The dehydrated ethanolamines then proceed to a further drying column, after which they are separated in a series of fractionating columns, not difficult because of the comparatively wide separation of their boiling points. 

Industrially, the ethanolamines are important because they form numerous derivatives, notably with fatty acids, soaps, esters, amides, and 

The soaps of the ethanolamines are extensively used in textile treating agents, in shampoos, and emulsifiers. The fatty acid amides of diethanolamine are applied as builders in heavy-duty detergents, particularly those in which alkylaryl sulfonates are the surfactant ingredients. The use of triethanolamine in photographic developing baths promotes fine grain structure in the film when developed. 

Ethanolamine also is used as a humectant and plasticizing agent for textiles, glues, and leather coatings and as a softening agent for numerous materials. Morpholine is an important derivative. 

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An example of mixed parallel and series reactions is the production of ethanolamines by reaction between ethylene oxide and ammonia ... 

H2N(CH2)jCOOH, C H,3N02. Prepared from -benzoylaminocapronitrile or from l-hydroxycyclohexylhydroperoxide, m.p. 205 0. Aminocaproic acid is an antifibrinolytic agent, used to treat thrombosis in the deep veins. amiDoethyl alcohol. See ethanolamines. 

The 5-nitrosallcylaldehyde reagent is prepared as follows. Add 0-5 g. of 5-nitrosalicylaldehyde (m.p. 124-125°) to 15 ml. of pure triethanolamine and 25 ml. of water shake until dissolved. Then introduce 0-5 g. of crystallised nickel chloride dissolved in a few ml. of water, and dilute to 100 ml. with water. If the triethanolamine contains some ethanolamine (thus causing a precipitate), it may be necessary to add a further 0 - 5 g. of the aldehyde and to filter off the resulting precipitate. The reagent is stable for long periods. 

CYCLOPENTADlENE AND DICYCLOPENTADlENE] (Vol 7) l-Hydroxy-4-methyl-6-(2,4,4-tri-methylpentyl)- 2-(lIT) pyridinone,ethanolamine salt [68890-66-4]... 

Lecithin. Lecithin [8002-43-5] (qv) is a mixture of fat-like compounds that includes phosphatidyl choline, phosphatidyl ethanolamines, inositol phosphatides, and other compounds (37). Commercial lecithin was originally obtained from egg yolks, but is now extracted from soybean oil. Lecithin is used in many products, including margarine, chocolate, ice cream, cake batter, and bread. 

Solvents used for hydrogen sulfide absorption include aqueous solutions of ethanolamine (monoethano1 amine, MEA), diethanolamine (DEA), and diisopropanolarnine (DIPA) among others ... 

An ammoniacal solution is added just before use to activate the hydrogen peroxide. Ammonia is preferred over sodium carbonate (40) or ethanolamines for maximum bleaching. The alkaline solution can be formulated iato a shampoo vehicle with oleate soaps or ethoxylated fatty alcohols. When the bleach is appHed to areas such as new hair growth, a viscous cream or paste may be preferred, formulated with fatty alcohols, alkanolamides, or other thickeners. 

Fig. 1. Chemical stmcture of phosphatidylcholine (PC) (1) and other related phosphohpids. R C O represents fatty acid residues. The choline fragment may be replaced by other moieties such as ethanolamine (2) to give phosphatidylethanolamine (PE), inositol (3) to give phosphatidylinositol (PI), serine (4), or glycerol (5). IfH replaces choline, the compound is phosphatidic acid (6). The corresponding lUPAC-lUB names ate (1), l,2-diacyl-t -glyceto(3)phosphocholine (2), l,2-diacyl-t -glyceto(3)phosphoethanolamine (3), 1,2-diacyl-t -glyceto(3)phosphoinositol (4), 1,2-diacyl-t -glyceto(3)phospho-L-serine and (5), l,2-diacyl-t -glyceto(3)phospho(3)-t -glycetol.

Hydrolysis. The first effect of either acid hydrolysis or alkaline hydrolysis (saponification) is the removal of the fatty acids. The saponification value of commercial lecithin is 196. Further decomposition into glycerol, phosphoric acid, and head groups (ie, choline, ethanolamine, etc) may foUow prolonged heating. Lecithin may also be hydrolyzed by enzymes. 

One of the principal aspects of refinery gas cleanup is the removal of acid gas constituents, ie, carbon dioxide, CO2, and hydrogen sulfide, H2S. Treatment of natural gas to remove the acid gas constituents is most often accompHshed by contacting the natural gas with an alkaline solution. The most commonly used treating solutions are aqueous solutions of the ethanolamines or alkah carbonates. There are several hydrogen sulfide removal processes (29), most of which are followed by a Claus plant that produces elemental sulfur from the hydrogen sulfide. 

Fig. 2. Flow sheet for ethanolamine production. EO = ethylene oxide MEA, DEA, and TEA ate defined in Table 1.

U.S. capacity of the etbanolamines ia 1989, almost one-half of global capacity, was estimated to be 379,000 t. Global capacity for 1989 was estimated at 692,000 t. Estimated annual U.S. production figures are Hsted in Table 3 (21). U.S. consumption of ethanolamines for various appHcations is shown in Table 4. 

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