Nitriles, saturated

At the request of an international petroleum company, a major manufacturer and supplier of down-hole equipment performed tests of the various elastomers commonly used in the construction of packers and other oil field tools. Seven of the nine most commonly used thermoplastic materials were found to be completely inert to TKPP solutions. The test included continual immersion in saturated TKPP for 21 days at 280°F. Only two elastomers, Vi-ton and Fluorel, showed any adverse reaction. O-rings made from these two elastomers showed minor cracking at the termination of the test. A listing of the elastomers that tested inert to TKPP solutions include nitrile, saturated nitrile (HNBR), Aflas, Kalrez, PEEK, Glass-filled Teflon, and Ryton. Several of these elastomers are attacked or degraded by conventional clear completion fluids containing calcium and zinc halides. The inertness of commonly employed elastomers to TKPP is an important advantage for TKPP fluids in normal operations. 

Homogeneous hydrogenation of nitriles, Saturated nitriles are hydrogenated to primary amines in 67-100% yield with 1 as catalyst in THF. The catalytic activity of 1 for aromatic nitriles is not so high as for hydrogenation of aliphatic nitriles. The C=C bond of unsaturated nitriles is reduced more readily than the C=N bond. This catalyst is also eflective for dehydrogenation of amines (benzylamine — benzonitrile, 27% yield). 

The reaction between a,/ -unsaturated nitriles and Grignard reagents was studied in a few cases [4]. With a,j -ethylenic nitriles, saturated [4,34-36] and vinylic [37] Grignard reagents lead to 1,4-addition products ... 

In a 25-mL, single-necked, round-bottomed flask equipped with a magnetic stirring bar was placed 0.21 g (0.5 nunol) of the nitrile. Saturated ethereal HCl (20 mL) was added with vigorous stirring, which resulted in the immediate formation of white precipitate. A few drops of lEP were added, and the reaction mixture was stirred at room temperature for 12 h. At this time the solution was diluted with ether (25 mL), and the precipitated hydrochloride was filtered and dried under vacuum to give the acid as a white solid (0.12g, 95%). 

However, the term saturated is often applied to compounds containing double or triple bonds which do not easily undergo addition reactions. Thus ethanoic acid is termed a saturated carboxylic acid and acetonitrile a saturated nitrile, whereas a Schiff base is considered to be unsaturated. 

The crude acetonitrile contains as impurity chiefly acetic acid, arising from the action of phosphoric acid on the acetamide. Therefore add to the nitrile about half its volume of water, and then add powdered dry potassium carbonate until the well-shaken mixture is saturated. The potassium carbonate neutralises any acetic acid present, and at the same time salts out the otherwise water-soluble nitrile as a separate upper layer. Allow to stand for 20 minutes with further occasional shaking. Now decant the mixed liquids into a separating-funnel, run off the lower carbonate layer as completely as possible, and then pour off the acetonitrile into a 25 ml, distilling-flask into which about 3-4 g. of phosphorus pentoxide have been placed immediately before. Fit a thermometer and water-condenser to the flask and distil the acetonitrile slowly, collecting the fraction of b.p. 79-82°. Yield 9 5 g. (12 ml.). 

From nitriles by treatment with anhydrous Stannous chloride dissolved in ether saturated with hydrogen chloride the resulting crystaUine aldimine stannichloride, [(RCH=NHj)2] SnCl, or (RCH=NH,HCl)2SnCl4, is hydrolysed by warm water, and the aldehyde is isolated by distillation with steam or by extraction with a solvent (Stephen reaction), for example, for R = CH3(CH2)4, i.e., n-amyl ... 

The iso-nitrile may be removed by the following procedure. Shake the crude (undistilled) n-butyl cyanide twice with about half its volume of concentrated hydrochloric acid and separate carefully after each washing then wash successively with water, saturated sodium bicarbonate solution and water. Dry with anhydrous calcium chloride or anhydrous calcium sulphate, and distil. Collect the pure n-butyl cyanide at 139-141°. If a fraction of low boiling point is obtained (because of incomplete drying), dry it again with anhydrous calcium sulphate and redistil. The yield is 95 g. 

After cooling to about 40°C (note 2) the viscous brown liquid was poured into a vigorously stirred solution of 50 g of ammonium chloride in 250 ml of 4 N HCl, which was kept at 0-5°C. The flask was also rinsed with this solution. The product was extracted 5-7 times with a 1 1 mixture of diethyl ether and pentane. The combined extracts were washed with saturated NHi Cl solution and subsequently dried over magnesium sulfate. The residue remaining after removal of the solvents in a water-pump vacuum, was carefully distilled through a 30-cm Widmer column. The desired nitrile, b.p. 84°C/15 mmHg, n 1.4487, was obtained in 72% yield. The first fraction (about 5 g) consisted mainly of the 1,3-substitution product n-C,HgC(CsN)=C=CH2. 

Chlorosulfonic acid Saturated and unsaturated acids, acid anhydrides, nitriles, acrolein, alcohols, ammonia, esters, HCl, HF, ketones, hydrogen peroxide, metal powders, nitric acid, organic materials, water... 

Nitrile latices are used ia a wide variety of appHcations, including production of dipped nitrile mbber products. In the principle use of paper saturation, adhesives and fiber bonding, small particle size and optimum surface tension is desirable to achieve rapid penetration and setup or dryiag. 

Highly saturated nitrile elastomers (HSN) have become available. These mbbers are prepared by (nearly complete) hydrogenation of the nitrile mbber copolymer. The resulting product has better heat and oxidation resistance than conventional nitrile mbber but still retains some double bonds for vulcanization. Trade names for HSN are Zetpol (Nippon Zeon), Therbar (Bayer), and Tormac (Polysar). HSN has been used, and is being developed, for oil field chemical, automotive, power station, aerospace, military, and industrial appHcations (66). 

Y. Kubo, K. Hashimoto, and N. Watanabe, "Stmcture and Properties of Highly Saturated Nitrile Elastomers," paper presented at theH.CA. 

K. Hashimoto and co-workers, "Highly Saturated Nitrile Elastomer, A Review," paper presented at theH.CA. Energy Rjibber Group, Dallas, Tex., Jan. 19,1989. 

Hydrogenated nitrile rubbers were introduced in the mid-1980s as Therban by Bayer. The initial grade had an acrylonitrile content of only 17% instead of approx. 34% in conventional NBR. Whilst non-sulphur-curing systems such as the use of peroxides with triallyl cyanurate or isocyanurate are necessary, the saturated rubber has a number of advantages over NBR. These include improved... 

The as-spun acrylic fibers must be thermally stabilized in order to preserve the molecular structure generated as the fibers are drawn. This is typically performed in air at temperatures between 200 and 400°C [8]. Control of the heating rate is essential, since the stabilization reactions are highly exothermic. Therefore, the time required to adequately stabilize PAN fibers can be several hours, but will depend on the size of the fibers, as well as on the composition of the oxidizing atmosphere. Their are numerous reactions that occur during this stabilization process, including oxidation, nitrile cyclization, and saturated carbon bond dehydration [7]. A summary of several fimctional groups which appear in stabilized PAN fiber can be seen in Fig. 3. 

Nickel peroxide is a solid, insoluble oxidant prepared by reaction of nickel (II) salts with hypochlorite or ozone in aqueous alkaline solution. This reagent when used in nonpolar medium is similar to, but more reactive than, activated manganese dioxide in selectively oxidizing allylic or acetylenic alcohols. It also reacts rapidly with amines, phenols, hydrazones and sulfides so that selective oxidation of allylic alcohols in the presence of these functionalities may not be possible. In basic media the oxidizing power of nickel peroxide is increased and saturated primary alcohols can be oxidized directly to carboxylic acids. In the presence of ammonia at —20°, primary allylic alcohols give amides while at elevated temperatures nitriles are formed. At elevated temperatures efficient cleavage of a-glycols, a-ketols... 

Chromium (II) sulfate is capable of reducing a variety of functional groups under mild conditions 10). Of particular interest is its ability to reduce a,jS-unsaturated esters, acids, and nitriles to the corresponding saturated compounds. This capability is illustrated in the procedure by the reduction of diethyl fumarate. 

The liquid nitrile rubbers are generally used as nonvolatile and nonextractable plasticizers. They also function as binders and modifiers for epoxy resins. Their moderate heat resistance limits their ability to meet industrial requirements. Hence, attempts have been made to improve their thermal and oxidative resistance by saturating the polymer backbone. 

Hydroformylation of nitrile rubber is another chemical modification that can incorporate a reactive aldehyde group into the diene part and further open up new synthetic routes to the formation of novel nitrile elastomers with a saturated backbone containing carboxyl or hydroxyl functionalities. 

Hydroformylated nitrile rubbers might have potential as binders for coupling with other rubbers due to the presence of polar aldehyde group. This might also open up the still greater potential of NBR containing saturated backbone in composite materials [1]. 

Treatment of 2-cyclohexenone with HCN/KCN yields a saturated keto nitrile rather than an unsaturated cyanohydrin. Show the structure of the product, and propose a I. mechanism for the reaction. 

Nitriles show an intense and easily recognizable C=N bond absorption near 2250 cm-1 for saturated compounds and 2230 cm-1 for aromatic and conjugated molecules. Since few other functional groups absorb in this region, IR spectroscopy is highly diagnostic for nitriles. 

Carboxylic acid groups can be detected by both and A3C NMR spectroscopy. Carboxyl carbon atoms absorb in the range 165 to 185 8 in the l3C NMR spectrum, with aromatic and unsaturated acids near the upheld end of the range (—165 8) and saturated aliphatic acids near the downfield end (—185 8). Nitrile carbons absorb in the range 115 to 130 8. 

Fragmentation The saturated aliphatic mononitriles with molecular weights greater than 69 are characterized by intense ions at m/z 41, 54, 68, 82, 96, 110, 124, 138, 152, 166, and so forth. Aliphatic nitriles undergo the McLafferty rearrangement producing the m/z 41 ion. 

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