Amides and Imidazolines

An amide-type corrosion inhibitor is prepared as follows Methylmethacrylate is converted with tallow triamine or tallow tetramine at 80° to 90° C into the corresponding amides. After completion, the temperature is raised to initiate the polymerization reaction [1350]. The polymerization reaction is performed at temperatures up to 200° C. The polymer controls the corrosion of metal surfaces in contact with a corrosive hydrocarbon-containing medium. 

Ammonium salts of alkenyl succinic half-amides have teen described for use as corrosion inhibitors in oil and gas production technology to combat corrosion by media containing CO2, H2S, and elemental sulfur [1366]. The inhibitor composition may contain a dispersing agent, such as a low molecular weight or polymeric anionic surfactant like an alkylsulfonic acid or an alkyl-aryl sulfonic acid. 

Ethoxylated and propoxylated alkylphenol amines, converted into the amides with a fatty acid or similar long chain diacids, are effective in controlling sour and sweet corrosion [1782,1783,1785-1787]. 

Tall oil fatty acids consist of resin acids (25% to 30%) and of a mixture of linolic acid, conjugated Cig fatty acids (45% to 65%), oleic acid (25% to 45%), 5,9,12-octadecatrienic acid (5% to 12%), and saturated fatty acids (1% to 3%). Resin acids are abietinic acid, dehydroabietic acid, and others. Properties of fatty acids are shown in Table 6-1. 

Corrosion inhibiting compositions for metals subjected to highly acidic environments may be produced by reacting in a condensation reaction a styrene/ maleic anhydride copolymer with a polyamine to produce a polyimidoamine inhibitor [1568]. These inhibitors exhibit film-forming and film-persistency characteristics. Some relevant polyamines are listed in Table 6-2. 

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Polyoxylated Amines, Amides, and Imidazolines Polyoxyalkylene Amines... 

Polyoxylated amines, amides, and imidazolines Nitrogen heterocyclics... 

Although acetonitrile is one of the more stable nitriles, it undergoes typical nitrile reactions and is used to produce many types of nitrogen-containing compounds, eg, amides (15), amines (16,17) higher molecular weight mono- and dinitriles (18,19) halogenated nitriles (20) ketones (21) isocyanates (22) heterocycles, eg, pyridines (23), and imidazolines (24). It can be trimerized to. f-trimethyltriazine (25) and has been telomerized with ethylene (26) and copolymerized with a-epoxides (27). 

Some examples of organic anionic inhibitors are sodium phosphates, thioureas and sodium MBT phosphionates (mercaptobenzothiazole). Some examples of organic cationic inhibitors are amines, amides, quaternary ammonium salts, and imidazoline. 

Imidazolines have been shown to have biological utility as antidepressants, and imidazoline ligands are known for a number of receptors widely distributed in both the peripheral and central nervous system.39 The imidazoline moiety has also been extensively studied as an amide bond... 

Recently, our group also contributed to CBD as a tool for DOS. By judicious selection of the reaction conditions, the 3CR between ot-acidic isocyanides 145 (isocyano amides and isocyano esters " ), carbonyl components 6 and primary amines 146 could be directed towards either 2//-2-imidazolines 150 or trisubsti-tuted oxazoles 152 (Scheme 13) [98]. 

Filming amine chemistry in the refinery includes amides, diamides and imidazoline salts. Each type is known to be effective in selected environments. The amino group is the important functional and salt-forming species. For readily handled commercial products, the amide intermediate is reacted with an imidazohne salt to enhance solubility in carrier solvents and to decrease gelling or phase separation. However, both groups are effective inhibitors. 

In 2008, Biswas and co-workers reviewed nitrogen containing monomers, for example fatty amines, fatty amides, fatty imidazolines, and polymers (PUs) made from soybean oil-based... 

Many RR-based products are used for this purpose. Amides of saturated and unsaturated fatty acids with alkanolamine, alkylamine, sarcosine and imidazoline are used in amounts of 0.1% in lubricants and greases. The salts of - fatty amines (Cg 18) with dialkyl phosphates are strong anticor-... 

Most of the inhibitors in use are organic nitrogen compounds and these have been classified by Bregman as (a) aliphatic fatty acid derivatives, b) imidazolines, (c) quaternaries, (d) rosin derivatives (complex amine mixtures based on abietic acid) all of these will tend to have long-chain hydrocarbons, e.g. CigH, as part of the structure, (e) petroleum sulphonic acid salts of long-chain diamines (preferred to the diamines), (/) other salts of diamines and (g) fatty amides of aliphatic diamines. Actual compounds in use in classes (a) to d) include oleic and naphthenic acid salts of n-tallowpropylenediamine diamines RNH(CH2) NH2 in which R is a carbon chain of 8-22 atoms and x = 2-10 and reaction products of diamines with acids from the partial oxidation of liquid hydrocarbons. Attention has also been drawn to polyethoxylated compounds in which the water solubility can be controlled by the amount of ethylene oxide added to the molecule. 

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]. 

Fig. 22 Possible reaction paths for the reaction between a-acidic isocyano amides (2 or 31), primary amines, and carbonyl components, including the Ag catalyzed formation of 2//-2-imidazolines (65)...

MCR also tolerates the aliphatic isocyanide functionality [150], thus allowing the union with various IMCRs. Finally, we developed the first example of a triple MCR process (SCR toward 83) based on our 2//-2-imidazoline (65) and W-(cyano-methyl)amide (32) MCRs united with the Ugi-4CR (Fig. 25). 

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. 

The Hulme group reported an efficient three-step, one-pot solution-phase synthesis of 2-imidazolines employing the UDC strategy [62], The reaction between N-Boc-protected a-aminoaldehydes, amines, acids, and isocyanides afforded the N-Boc-protected a-acylamino amides 94 which, upon heating in addic medium, underwent N-deprotection and cyclization to 2-imidazolines 95 (Scheme 2.34). This procedure was adapted to combinatorial synthesis in a rack of 96 reaction vials. 

The reactions of 3-amido-l-hydroxyazetidin-2-ones 327 with />-toluenesulfonyl chloride in the presence of triethyl-amine provided the ring-expanded 4-imidazolin-2-ones 328 (Equation 114) <1995TL1617>. The key step in the mechanism of this reaction involved the ring opening by cleavage of the C(2)-G(3) bond, which is followed by double bond migration and an intramolecular nucleophilic addition of the amide nitrogen to an intermediate isocyanate. 

It has to be noted that the formation of oxazoles using isocyano amides has been well studied by Zhu and co-workers (see [58, 59]). With the work of Elders et al. the oxazole MCR has been expanded with a wide range of isocyano esters. The MCR with isocyano amides can now also he directed to the 2-imidazolines. 

An elaboration of this work involves the 3CR between primary a-isocyanoa-mides 67, carbonyl components 6 and primary amines 146, which could be directed towards either 2//-2-imidazolines 153 or M-(cyanomethyl)amides 156 by Ag -catalysis vs. Brpnsted acid mediated reaction, respectively (Scheme 14) [60]. The selective formation of M-(cyanomethyl)amides 156 (also earlier mentioned in the SRR approach. Scheme 7) can be rationalized by the same criteria as the formation of trisubstituted oxazoles 152 (Scheme 13), since the use of a Brpnsted acid, prevents the formation of 2-imidazolines 153 by the decreased pH. By applying a Brpnsted acid, the reaction initially proceeds via the same mechanism as for the oxazole MCR. However, when intermediate 155 is formed, it does not tautomerize to form the 5-aminooxazole 157. Instead, proton abstraction at the exocyclic imine nitrogen and subsequent ring opening gave the corresponding M-(cyanomethyl)amides 156. 

Scheme 14 Directing the MCR towards 2//-2-imidazolines 153 and A -(cyanomethyl)anudes 156 and the suggested mechanism for the formation of W-(cyanomethyl)amides 156...

Interestingly, it was even possible to combine the 2-imidazoline and the M-(cyanomethyl)amide 3CRs with the U-4CR to afford a novel 8-component reaction, which is a landmark in this field [103]. 

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