In nitro

Nucleophilic Substitution in Nitro Substituted Aryl Halides... 

NUCLEOPHILIC SUBSTITUTION IN NITRO-SUBSTITUTED ARYL HALIDES... 

High performance Hquid chromatography (hplc) may be used to determine nitroparaffins by utilizing a standard uv detector at 254 nm. This method is particularly appHcable to small amounts of nitroparaffins present, eg, in nitro alcohols (qv), which caimot be analyzed easily by gas chromatography. Suitable methods for monitoring and deterrnination of airborne nitromethane, nitroethane, and 2-nitropropane have been pubUshed by the National Institute of Occupational Safety and Health (NIOSH) (97). Ordinary sorbant tubes containing charcoal are unsatisfactory, because the nitroparaffins decompose on it unless the tubes are held in dry ice and analyzed as soon after collection as possible. 

Adolph, H G, Koppes, W M In Nitro Compounds Recent Advances in Synthesis and Chemistry, Feuer,H, Nielson, A T,Eds, VCH Publishers New York, 1990... 

Strong acids or superacid systems generate stable fluorinated carbocations [40, 42] Treatment of tetrafluorobenzbarrelene with arenesulfonyl chlorides in nitro-methane-lithium perchlorate yields a crystalline salt with a rearranged benzo barrelene skeleton [43] Ionization of polycyclic adducts of difluorocarbene and derivatives of bornadiene with antimony pentafluonde in fluorosulfonyl chloride yields stable cations [44, 45]... 

The generally accepted mechanism for nucleophilic aromatic substitution in nitro-substituted aryl halides, illustrated for the reaction of p-fluoronitrobenzene with sodium methoxide, is outlined in Figure 23.3. It is a two-step addition-elimination mechanism, in which addition of the nucleophile to the aryl halide is followed by elimination of the halide leaving group. Figure 23.4 shows the structure of the key intermediate. The mechanism is consistent with the following experimental observations ... 

A typical value for the N O distance in nitro complexes is 124 pm whereas in nitrito complexes the terminal N-O (121pm) is shorter than the internal N-O(M) 129 pm. In the bidentate chelating mode (iii) the 2 M O distances may be fairly similar as in [Cu(bipy)2(02N)]N03 or quite different as in [Cu(bipy)(02N)2] ... 

Several ad hoc studies and discussions in recent years have been centered around the mechanism of aromatic substitution in nitro-activated benzene derivatives. The subject has been reviewed authoritatively. ... 

Palladium, platinum, or nickel, supported or unsupported, are the metals usually used in nitro-group reductions. The choice of catalyst often depends on what other functions are present and on the products desired,... 

The nucleophilic substitution of the nitro group in nitro-arene complexes works almost as well as that of Cl" and such substitutions were achieved by Chowdhurry et al. with O, S, and N nucleophiles and with stabilized carbanions [97,98] Eq. (28) and Table 8. 

Toxicity. Unknown, but should be hazardous considering other glycidyl compds Refs 1) PJ. Blatz et al, Research in Nitro Polymers and Their Application to Solid Smoke-... 

Refs J) W. Brooks et al, Research In Nitro- ° polymers And Their Application To Solid... 

Ref PJ. Blatz et al, Research In Nitro Polymers and Their Application To Solid Smokeless Propellants , Report No 622, Aerojet Engrg Corp, Azusa, Calif, ONR Contract N7 onr-462, Task Order I, (26 June 1952), appendix 41-44... 

The post nitrated polymer has a Qc of 2832 cal/g (liq H20 at 25°), an impact sensy of 90cm at the 50% point using a BM machine with a 2kg wt (RDX, 28cm), a thermal stability at 65.5° of 10 mins using a 1.3g sample with KI-Starch indicator paper (Ref NC, 10 mins, no color), and a rel vise of 1.13 centipoises at 25° using a 1% dimethylformamide soln Refs 1) P.J. Blatzet al, Research In Nitro-polymers and Their Application To Solid Smokeless Propellants , Report No 740, Aerojet-General Corp, Azusa, Calif, ONR Contract N7 onr-462, Task Order 1(15 Sept 1953), 26 2)... 

N = 0 in nitro compds, nitric acid esters and salts... 

In general, nitrations in nitromethane show a greater tendency towards zeroth-order kinetics, so that, for example, whereas benzene gives first-order kinetics on nitration by 7.0 M nitric acid in acetic acid (Table 13), in nitro-... 

In Nitro-pyrazol kann die Nitro-Gruppe durch Zinn(II)-chlorid in verdunnter Kalilauge zur Nitroso-Gruppe ([Nitroso-pyrazol) reduziert werden (s. Bd. X/l, S. 1064). 

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