Amine borates

Nitrite substitutes can be divided into seven chemical categories (1) amine benzoates (2) fatty acid amines (3) phosphate or carbonate silicates (4) organophosphates (5) amine borates (6) alkanolamines and (7) quaternary ammonium compounds ("quats"). Thus, the technology already exists for replacing nitrite with no loss in rust protection. However, most replacements for nitrite are more expensive, less effective, less likely to be compatible with other additives, and work by a different mechanism (12). It is therefore not surprising that fluids containing nitrite are still relatively com mon. 

The chemistry of reactive species formed from one-electron oxidation of amines, borate salts, group 4 a organometallics, bibenzyls, arenes and olefins will be treated separately in this section. 

Most nonmetal borates reported in the literature are ammonium and substituted ammonium salts, hi general, boric acid forms salts with alkyl- or aryl-amines that are roughly as or more basic than pyridine. Depending on the reaction conditions, a number of different crystalline borates might be isolated from a given amine. However, the chemistry of substituted amine borates is dominated by the occurrence of pentaborates, and relatively few compounds in this class have been reported containing more basic borates anions. 

Hot carbonates are well suited for the removal of C02 at moderate or high levels in the presence of little or no H2S. The process acquired its name from the use of elevated temperatures in both the absorber and the regenerator (110—115°C). Hot carbonates such as the Benfield and the Koppers Vacuum Carbonate utilize K2C03 to remove H2S, COS, and C02 from gas streams [35]. Their heat requirements and high solvent circulation make hot carbonates more expensive than other acid gas removal processes. Other hot carbonate processes, including the Catacarb and the Giammarco-Vetrocoke processes, use catalysts, corrosion inhibitors, and/or activators to enhance the removal of the acid gases. Hot carbonate-promoted systems are able to decrease the C02 level from 1% to 0.1%. Promoters include DEA, amine borates, and hindered amines [36]. 

N, disecbutyl p-phenylene-diamine amine borates amine guanidine derivatives esters of dithiophosphoric acid... 

The Catacarb Process uses an additive on the basis of amine borates, whose composition is not disclosed by the licensor. 

Uses Emulsifier for semi-syn, coolants, other water-dilutable products Features Free of DEA, ethanol amines, borates, NDELA, nitrite, oil low acid no, ... 

Alcohols react with boric acid with elimination of water to form borate esters, B(OR)3. A wide variety of borate salts and complexes have been prepared by the reaction of boric acid and inorganic bases, amines, and heavy-metal cations or oxyanions (44,45). Fusion with metal oxides yields... 

A recent adaptation of the procedure employing perchlorate and fluoro-borate salts has been reported by Leonard and Paukstelis (J5). This report includes proof of structure by direct comparison to iminium salts prepared by protonation of enamines. The general reaction reported was that of a ketone or aldehyde with a secondary amine perchlorate to give iminium salts. A large structural variety of carbonyl compounds and several amine... 

The stereochemical course of reduction of imonium salts by Grignard reagents was found to depend on the structure of the reagent 714). Hydro-boration of enamines and oxidation with hydrogen peroxide led to amino-alcohols (7/5). While aluminum hydrogen dichloride reacted with enamines to yield mostly saturated amines and some olefins on hydrolysis, aluminum hydride gave predominantly the unsaturated products 716). 

There has been much activity in this field of corrosion inhibition in recent years which appears to have been prompted by health and safety requirements. As with engine coolants, the use of nitrites, particularly where amines may also be present, needs to be considered carefully. Nitrites have been widely used in cutting, grinding, penetrating, drawing and hydraulic oils. Suggested replacements for nitrites and/or amines make use, inter alia, of various borate compounds, e.g. monoalkanolamide borates. Molybdates have also been proposed in conjunction with other inhibitors, e.g. carbox-ylates, phosphates, etc . Water-based metalworking fluids usually contain other additives in addition to corrosion inhibitors, e.g. for hard-water stability, anti-foam, bactericidal proderties and so on. Thus, claims are made for oil-in-water emulsions with bactericidal and anti-corrosion properties. 

Nitration of 9-methylpyrido[2,3-(t][l,5]benzoxazepin-5(6//)-one with nitronium tetrafluoro-borate gives exclusively the 7-nitro derivative 3, which is reduced to the amine 4 with iron/acetic acid.41... 

The synthesis of this ring system was achieved by the reaction of the ketene aminal 79 with 3-morpholino-l-ethyl-l,2,4-triazinium tetrafluoro-borate 78 to give 80 (89IZV494). Cyclization of 78 with the bifunctional nucleophile 81 gave the pyrrolo[3,2-e][l,2,4]triazinones 82 (88TL1431). This reaction represents the first example of orthocyclization onto the 1,2,4-triazine ring by the addition of dienophiles at C-5,6 (Scheme 20). 

Milner (1992) recently described a novel and versatile modification of the Balz-Schiemann reaction. The amine is diazotized with solid nitrosonium tetrafluoro-borate in CH2C12 and, without isolation, the diazonium salt is heated and yields the fluoroarene in good yield. The method is also applicable to aniline derivatives bearing carboxy and hydroxy substituents, compounds which give poor yields in the classical procedure. 

Natrium-trithio-dihydrido-borat Amin, (Thioamid) 14... 

Mit Lithium-cyano-trihydrido-borat werden in wasserfreiem Methanol bei pH 5-6 ebenfalls Amine erhalten z.B.4 ... 

Zu einer Suspension von 0,275 g (2 mMol) 2-Formyl-4-butanolid-Natriumsalz, 0,325 g (4 mMol) Dimethyl-amin-Hydrochlorid und 0,25 g Linde 3 A Molekularsieb gibt man 0,13 g (2 mMol) Natrium-cyano-trihydrido-borat und riihrt 24 Stdn. Danach filtriert man iiber Celite, wascht mit 10 ml Methanol und sauert das Filtrat mit... 

Die reduktive Methylierung von Aminen mit Formaldehyd ist (im Gegensatz zur ent-sprechenden Reaktion mit Natriumboranat) mit Natrium-cyano-trihydrido-borat nicht in Methanol, sondern in Acetonitril durchzufiihren. Aliphatische Amine reagieren meist hef-tig, aromatische langsamer10, n z.B. ... 

Bei der Reduktion von Oximen mit Natrium-trithio-dihydrido-borat werden meist Gemische von Hydroxylamin und prim. Amin gebildet3. Natriumboranat/Silicagel reduziert Oxime in Benzol-Lo-sungzu Hydroxylamin - Boranen, die durch Salzsiiure in die N-Alky] - hydroxylamin-Hydrochloride iibergefiihrt werden4. 

The most common corrosion inhibitors, which may form protective films on the metal surfaces, are borates, molybdates, nitrates, nitrites, phosphates, silicates, amines, triazoles, and thiazioles (e.g., monoethanolamine, urotropin, thiodiglycol, and mercaptobenzothiazole). The addition of such inhibitors does not effectively protect against corrosion [137]. Some corrosion inhibitors are shown in Figure 14-3. 

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