Na/NH3 treatment

Table 6 Na/NH3 Treatment of Surfaces Contaminated with Chemical Warfare Agents ... 

Table 8 Na/NH3 Treatment of Dioxins in Waste Oil at the McCormick and Baxter Site...

Table 9 Na/NH3 Treatment of a Transformer Oil Spill at a New York State Utility Site... 

Several postprocesses can be used to remove metals that still contaminate soils or other matrices after Na/NH3 treatment [43,44], Washing a treated soil with NH3/H20, at high pH using in situ-generated NaOH, was demonstrated in a mobile destruction unit used on-site at Lockheed/Martin Advanced Environmental Systems in Las Vegas, NM. Soil contaminated with 12,000 ppm of Aroclor 1260 and with cobalt (Co), cesium (Cs), and other metals at levels from 85 to 1800 ppm were treated first with Na/NH3 to destroy the PCBs. PCB destruction efficiencies were in excess of 99.9%. After the first posttreatment NH3/H20/Na0H extraction, 16-93% of each metal species was removed (Table 15). After the second extraction, the removal efficiencies increased from a low of 81% to a high of 97%. Thus, the majority of metals were removed in only two batch extractions. 

Botta and coworkers recently developed an Oxone cleavage methodology for the solid-phase synthesis of substituted uracils (equation 57)165. Whereas some common methods of thioether cleavage, such as reduction with Na/NH3, acid catalyzed hydrolysis, heavy metal ions followed by treatment with hydrogen sulfide and iodotrimethylsilane proved to be unsuccessful for this reduction, Oxone was shown to be an efficient and selective reagent for cleavage of polymer bound thiouracils. 

Alkenes from p-oxygenated selenidesS /J-Phenylseleno lactones, ethers, and alcohols are converted into alkenes on treatment with ClSi(CHj)j and Nal in C HiCN. Hydriodic acid (formed by inadvertent hydrolysis) may play a role this acid cun effect this reaction, but in lower yield. This elimination thus reverses cyclo-(unclionali/ations induced by C6H5ScX (cf Na-NH3, 9, 26), and in addition provides a stereospecific route to alkenes by way of/l-hydroxv selenides. lixnmplc ... 

Diastereoselective macrocyclizjation.1 A key step in a synthesis of the 14-membered cembranoid asperdiol (4) involves intramolecular cyclization of the aldehydo allylic bromide (1) with chromium(II) chloride. The intermolecular version of this reaction is known to be awft-selective (8,112). Treatment of racemic 1 with CrCl2 (5 equiv., THF) results in a 4 1 mixture of the two anri-diastereomers 2 and 3 in 64% combined yield. The stereochemistry of this cyclization is evidently controlled by the remote epoxide group. The natural product was obtained by deprotection of 2 (Na/NH3, 51% yield). 

An achiral hydrocarbon A of molecular formula C7H12 reacts with two equivalents of H2 in the presence of Pd-C to form CH3CH2CH2CH2CH(CH3)2. One oxidative cleavage product formed by the treatment of A with O3 is CH3COOH. Reaction of A with H2 and Lindlar catalyst forms B, and reaction of A with Na, NH3 forms C. (a) Identify compounds A, B, and C. (b) Explain why A does not react with NaH. 

Treatment of a PMP ether with Na/NH3 results in the formation of an enol either, which in principle can be hydrolyzed to release the alcohol. ... 

The synthesis of the fragment C3-C13 was achieved in five steps from 169. Treatment of the tosylated stereotetrad 169 with 5 equivalents of lithium acetylide in DMSO led an acetylenic compound which was treated with ra-Buli and methyl iodide, and then reduced by Na/NH3 to produce the E-geometry of the C12-C13 double bond with concomitant removal of the PMB group at C5, giving the primary alcohol 170 (49% yield for the three-step sequence). Swern oxidation of 170 gave the corresponding aldehyde which was involved in an Evans-type asymmetric aldol reaction with the boron enolate A to produce the adduct 171 (dr > 95/5, 90% yield). (Scheme 33). 

Of importance in connection with the solubility of the metals in liquid ammonia are ammonia solvates such as the [Na(NH3)4]+ ion which is formed on treatment of Nal with liquid ammonia. [Na(NH3)4]I is a liquid of fair thermal stability. It freezes at 3° and at 25° has an equilibrium pressure of NH3 of 420 mm thus it must be kept in an atmosphere of ammonia with at least this pressure at 25°. The infrared and Raman spectra indicate the complex ion [Na(NH3)4]+ to be tetrahedral with Na—N bonds about as strong as the Zn—N bonds in [Zn(NH3)4]2+ or the Pb—C bonds in Pb(CH3)4. Bending and rocking frequencies, however, are quite low, suggesting that the Na—N bonding is mainly due to ion-dipole forces. Thus it may be assumed that Na+ and other metal ions in the dilute liquid ammonia, amine and ether solutions are strongly solvated in the same way. 

The Bedford Harbor sample discussed in Table 7 shows another advantage of Na/NH3(i) treatment. The levels of toxic metals present in the sample were greatly reduced in this remediation. Methods using Na/NH3 to decontaminate metals from soils are discussed in US Patents 5,516,968 (1996) and 5,613,238 (1997). 

In addition, an asymmetric synthesis of (R)-tolterodine, a potent muscarinic receptor antagonist used on a worldwide basis for the treatment of urge incontinence, was devised by MacMillan s group. Their own imidazohdinone-mediated electrophilic aromatic substitutions of aniUnes in concert with a new methodology for aryl ammonium reduction (MeOTf/Na /NH3) gave rise to the above-mentioned pharmaceutical agent in a concise and elEcient manner (Scheme 35.27). 

Ni(NH3 )6 (Cl04>2- Lavender crysts, prepd as follows to a soln of 23.8g of Ni dichloride and 5.4g of Amm chloride in 125ml of w is added 14.0g of Na perchlorate in 50ml of w, followed by the slow addn with stirring of 60ml of coned aq ammonia. The mixt is chilled for 4 hours in. an ice bath and the solid filtered to give 48% of the hexaammoniate which is free of chloride (Ref 11). It also can be prepd by treatment of an O-free aq soln of Ni perchlorate contg an... 

The inertness of phenols and phenoxy phenols toward Na/liq. NH3 can be attributed to the fact that phenols are powerful proton-donors in this system, and resistance of the resultant anions toward reduction is believed to result from stabilization by resonance (10). While alkylation of low-rank coals before treatment with Na/liq. NH3 therefore offers means for establishing the presence of phenoxy phenol ethers in them, an alternative is afforded by the observation that some phenols can be reduced by concentrated solutions of lithium (11). If this latter reaction also reduces phenoxy phenols in coal, a second treatment should then cause ether-cleavage. 

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