M nitration

Wheland intermediate (see below) as its model for the transition state. In this form it is illustrated by the case mentioned above, that of nitration of the phenyltrimethylammonium ion. For this case the transition state for -nitration is represented by (v) and that for p-substitution by (vi). It is argued that electrostatic repulsions in the former are smaller than in the latter, so that m-nitration is favoured, though it is associated rvith deactivation. Similar descriptions can be given for the gross effects of other substituents upon orientation. 

Complexation of bromine with iron(III) bromide makes bromine more elec trophilic and it attacks benzene to give a cyclohexadienyl intermediate as shown m step 1 of the mechanism (Figure 12 6) In step 2 as m nitration and sulfonation loss of a proton from the cyclohexadienyl cation is rapid and gives the product of electrophilic aromatic substitution... 

Nitromum tetrafluoroborate, from nitric acid, boron tnfluonde, and hy drogen fluoride, 47, 56 m nitration of aromatic rings, 47,... 

The precision of the method is better than 0.2%o (1 SD) at concentrations of nitrate down to 1 p,M, and the nitrogen isotopic differences among various standards and samples are accurately reproduced. For samples with 1 p,M nitrate or more, the blank of the method is less than 10% of the signal size, and various approaches may reduce it further. 

The tertiary and quaternary amine bases are viscous liquids at room temperature and infinitely soluble in nonpolar solvents, but only slightly soluble in water. The solubility of the ion-pair RNH L in organic solvents depends on the chain length and on the counterion, LT the solubility of TLA HCl in wet benzene is 0.7 M, in cyclohexane 0.08 M, in CHCI3 1.2 M, and in CCI4 0.7 M. Nitrate and perchlorate salts are less soluble, as are lower molecular weight amines. 

A -M -substituted Carbonates route A, M -nitrates, 1000-1200 Ba,La-p-Al203 or Catalytic 22-24,... 

A second principal use of liquid ammonia involves forming a suspension of an alkali metal amide (LiNH2, KNH2 or NaNH2) by adding the appropriate metal to liquid ammonia containing a trace of iron(m) ions (added as iron(m) nitrate) as a catalyst. 

A variant solvent formulation was developed in China (INET), involving (2-ethylhexyl)-phosphonic acid 2-ethylhexyl ester (HEHEHP) as the extractant (saponified to 40% with concentrated ammonia), dissolved at 1.5 M in kerosene, to recover, in 43 stages, 99% of Am(III) and remove 90% of Ln(III) from a 0.2 M nitrate feed (pH 1) (237). 

A silicon atom might be expected to release electrons inductively, but because of empty -orbitals shows the overall character (+/ —M). Nitration of trimethylsilylbenzene62 with nitric acid in acetic anhydride at —10 too °C gives 25-5,39-8,30-2 and 6-8 %, respectively, of 0-, m-, and p-nitro-trimethylsilylbenzene and nitrobenzene, with a rate of reaction relative to that of benzene of about 1-5. The figures give no indication of an important conjugative effect. 

Liquid ammonia (700-800 ml) is placed in the 2-1 flask. Stimng is started and 400 mg (note 1) of iron(m)nitrate (hydrate) is added, followed after an interval of 10 s by 2 to 4 g of sodium. As soon as the blue colour has disappeared, the remainder of the 1.0 mol of sodium is cut in to the grey to black solution (colloidal zerovalent Fe). The conversion into NaNH2 (compare ref.l) takes, as a rule, 25 to 30 min. The volume of the greyish, coarse suspension which has formed, is about 500 ml. Triphenylmethane (0.5 g) is added whereupon a reddish colour is developed. Acetylene (1 to 1.5 1/min) is introduced with efficient stimng. The suspension gradually disappears (note 2). The introduction of acetylene is stopped (removal of the inlet tube) when the red colour has disappeared. Sometimes the colour may reappear, in that case the introduction of acetylene is recontinued far a short time. 

Hydrophilic xenobiotics uv/h2o2 CFPR, C0 about 10 M. Nitrate influence, kinetics 173... 

Bismuth(m) nitrate catalyzes Michael addition of a,/Yunsaturated ketones with amines, thiols, and carbamates, although the promoting role of Bi(N03)3 is not fully understood (Equation (91)).100 The Biginelli cyclocondensation of a mixture of (3-keto esters, aldehydes, and urea is mediated by BiCl3, affording 3,4-dihydropyrimidin-2(lH)-ones (Equation (92)).149 Bi(OCOCF3)3 is an efficient catalyst for the regio- and chemoselective synthesis of /3-enaminones in water.150... 

We used HZSM-5 zeolites (Si02/AI203 = 40 - 120) and H[Ga]ZSM-5 zeolites (Si02/AI203 = 60) prepared by decationization of the Na-form with a 1 N aqueous solution of HCI. The preliminary activation of all catalyst samples was carried out at temperatures of 820 - 1120 K either in an Ar flow or in an air flow for 6 h. For comparison, we prepared the HZSM-5 zeolite modified by 2 wt % Cu (wet impregnation with a 1 M nitrate solution with further nitrate decomposition at 820 K in air) and tested this sample in the fluorobenzene oxidation by nitrous oxide. 

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