Ethanolamine

Ethanolamine. Ethanolamine (NH2CH2CH20H)-based anisotropic etchants have been developed so as to replace the toxic EDP etchant. ° Linde and Austin reported a functional formula of 100 g gallic acid -1- 305 ml ethanolamine -1- 140ml water 

PTGURE 7.26. Silicon etch rate as a function of TMAH concentration. After Thong et al.  

Gallic acid functions as an effective sihcon complexing agent in aqueous ethanolamine solutions. In its absence the etch rate is zero. Etch rate increases with water content. The additions of pyrazines, pyridazines, and triazoles show various catalytic effects on the etching process. The catalysts that lead to faster oxidation result in faster etch rates, and the difference among the catalysts is due to a steric effect. Oxidative catalysts tend to influence the etching selectivity of the major crystal 

ESTERS OF AMINOBENZOIC ACIDS AND ALKANOLAMINES a. Derivatives of Ethanolamine 

A chance observation made some time prior to the full structural elucidation of cocaine in fact led to one of the more important lasses of local anesthetics. It was found that the simple ethyl e. ter of p-aminobenzoic acid, benzocaine (25), showed activity. 1-. a local anesthetic. It is of interest to note that this drug, I 1rst introduced in 1903, is still in use today. Once the struc-iiire of cocaine was established, the presence of an alkanolamine iiiniety in cocaine prompted medicinal chemists to prepare esters I aminobenzoic acids with acyclic alkanolamines. Formula 26 11 presents the putative relationship of the target substances with cocaine. 

Preparation of the prototype in this series, procaine (31). i.irts with the oxidation of p-nitrotoluene (27) to the corre-Hiding benzoic acid (28). This is then converted to the acid ll Inride (29) reaction of the halide with diethyl aminoethanol fiI lords the so-called basic ester (30). Reduction by any of a .fl ics of standard methods (e.g., iron and mineral acid, cata-Ivlic reduction) affords procaine (31).  

The structure of the side chain carrying the aliphatic basic nitrogen atom shows the same lack of structural demand for biologic activity as does the exact nature of the substitution pattern in the aromatic ring. 

acylation of 3(W,iV-dibutylamino)propanol (39) with p-nitrobenzoyl chloride affords the intermediate, 40. Reduction of the nitro group gives butacaine (41), an agent equipotent as cocaine as a topical anesthetic. 

FIGURE 6.6 Phosphatidylcholine (PC) synthesis by phosphatidylserine (PS) decarboxylation and base exchange. Serine serves as the source of the carbon skeleton of choline. 

Choline, supplied as dietary PC or as free choline, is required in the diet by rats. Although it has not been established that choline is required by humans, it is probably an essential nutrient and may, in the future, be classified as an essential amine or vitamin. Its possible requirement is a concern to clinicians feeding patients by total parenteral nutrition (TPN). In this type of feeding, which may be used for a year or longer, the patient is sustained intravenously with an artificial, chemically defined diet. The choline in foods occurs mainly as PC rather than as free choline. PC is a more desirable dietary component because, when free choline is consumed in large amoimts, it is degraded by the gut bacteria to produce trimethylamine, an odoriferous compound (Magil et al, 1981). 

The concentrations of choline in various foods are given in Table 6.2. This nutrient occurs as free choline, PC, and sphingomyelin. Concentrations are expressed on a molar basis, allowing direct comparison of choline levels, because 1 mol PC or sphingomyelin contains 1 mol choline. 

Ethanolamine occurs in the diet mainly as PE, not as free ethanolamine. PC and PE are present in similar quantities in some foods. PE can be converted to PC in the liver. Therefore, the PE normally present in the diet should reduce the require- 

TABLE 6JZ Content of Free and Bound Choline in Foods 

The ACGIH has not assigned a numerical threshold limit value (TLV) for occupational exposure to ethane because the limiting factor is the available oxygen, the minimal content which should be 18% by volume under normal atmospheric pressure at concentrations below those required to produce severe oxygen deprivation, ethane presents an explosive hazard.  

ACGIH Ethane. Documentation of the Threshold Limit Values and Biological Exposure Indices, 7th ed, p 2. Cincinnati, OH, American Conference of Governmental Industrial Hygienists (ACGIH), 2001 

Sax NI Dangerous Properties of Industrial Materials, 6th ed, p 313. New York, Van Nostrand Reinhold Co, Inc, 1984 

Synonyms 2-Aminoethanol 2-hydroxyethy-lamine ethylolamine colamine monoethano-lamine 

As a chemical intermediate corrosion inhibitor in the production of cosmetics, detergents, paints, and polishes 

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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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