Chloride sources

Ammonium chloride source of nitrogen (required for synthesis of proteins, nudeic adds and co-enzymes). 

In a recent study, some mechanistic aspects of this templated process have been determined quantitatively [28]. Using UV-Vis spectroscopy to monitor the kinetics of the macrocyclization reaction, it has been established that the rate of ring closure of the cationic precursor to the [ljimidazoliophane (4) is increased up to ten times in the presence of 0.04 mol/1 solution of a chloride source. The chloride stabilizes the transition state (i.e. a kinetic template) favouring the macrocyclization through hydrogen bonding. 

The group of Williams has reported a DKR of halo a-bromo [33a] and a-chloro esters [33b]. In the latter case, the KR is catalyzed by commercially available cross-linked enzyme crystals derived from Candida cylindracea lipase. The racemization takes place through halide SN2 displacement. The DKR is possible because the racemization of the substrates is faster than that of the products (carboxylates). For the ester, the empty ( =0) orbital is able to stabilize the SN2 transition state by accepting electron density. However, the carboxylate is more electron-rich and therefore less able to facilitate an SN2 reaction. Racemization is performed by the use of a chloride source. The best results where obtained by using a resin-bound phosphonium choride (Scheme 5.17). 

Fe203 and Fe304 in presence of a chloride source act as flame retardants for nitrile-containing plastics and rubbers such as acrylonitrile-butadiene-styrene copolymers.52 The activity appears to be connected with the formation of FeCl3 on combustion, but other properties of FeCl3 itself make it unsuitable for direct use. If an alkyl chloride is present iron(II) citrate may be used, and for halogen-containing nitrile polymers acetates, stearates, sulfates and carbonates are effective. 

Phosphorus-nitrogen arsenic-chlorine type Alkali metal salt thermionic type Potassium chloride source for phosphorus compounds, rubidium source for nitrogen compounds [397]... 

Activation of such homoleptic trimethylaluminum adduct complexes with 1 -3 equivalents of the chloride source Et2AlCl produced binary catalyst mixtures revealing the expected activity and cis- 1,4-stereospecificity in isoprene polymerization (Table 9) [142]. High-yield polymeric materials with relatively narrow molecular weight distributions were obtained. No activity was observed for a n(Cl) n(Ln) ratio of 3 1. 

An improvement of the previously reported Meerwein protocols was achieved by employing ionic liquids as chloride sources (Scheme 18) [93], Although this new version of the Meerwein reaction is still limited to activated alkenes such as acrylates, electron-donating as well as electron-withdrawing groups on the diazo-nium salt are tolerated. In earlier Meerwein arylations, a change in the substitution... 

The formation of the expected 2,4,6-trisilaalkanes 2 can be explained by the 2 1 reaction of (chloromethyl)silanes 1 and elemental silicon. The byproducts, 1,3-disilaalkanes 3, were obtained from the reaction of (chloromethyl)silane reactant 1 and hydrogen chloride (or chlorine) with the same silicon atom, as methyldichlorosilane (or methyltrichlorosilane) was obtained from the methyl chloride reaction. This result indicates that some of the (chloromethyl)silane reactant decomposed under the reaction conditions and acted as a chlorine or hydrogen chloride source. In the direct reaction of (chloromethyl)dimethylchlorosilane (lc), a significant amount of starting material was recovered at temperatures below 300 °C, but the reaction went to completion above 320 °C. 2,6-Dimethyl-2,4,4,6-tetra-chloro-2,4,6-trisilaheptane (2c) was obtained in much higher yields than 3-methyl-l,l,l,3-tetrachloro-l,3-disilabutane (3c) at reaction temperatures ranging from 280 to 320 °C, but the ratio of both compounds reversed above 340 °C. 

Recently, the reactivity of N-heterocyclic carbenes with bromine and some chloride sources were reported. Imidazolium chloride salts are sometimes obtained as side products when carbene (1) is reacted with main group species to produce main group carbene adducts. However, they can be prepared directly from the reaction of carbene (1) (R = Mes, R = H) with chloroalkanes, such as hexachloroethane in acetonitrile (134). Reaction of carbene (1) (R = Mes, R = H) with Br2 or 1,2-dibromoethane affords the 2-bromo-l,3-bis(2,4,6-trimethylphenyl) imidazolium bromide (135). 

This complex is preurfo-tetrahedral and isonumeral with [Hf(r -C5H5)2(NR2)2]. Acids such as 2,6-Me2CsH30H and water can cleave the W-NH Bu bonds, and W-Cl bonds can be introduced by the use of chloride sources. 

Figure 2.22. Excess adsorption of methanol from methanol + benzene mbctures on mont-mortllonite treated wnth increasing amounts (from I to 4) of hexadecylpyrldinium chloride. (Source as (Ig. 2.21.)...

Izbicki J. A. (1991) Chloride sources in a California coastal aquifer. In Ground Water in the Pacific Rim Countries. Conference Proceedings, Irrigation Division, American Society of Consulting Engineers, Honolulu, Hi, July 23-35, 1991. 

Lee JC, Fialkow PJ. Benzalkonium chloride-source of hospital infection with Gram-negative bacteria. JAMA 1961 177 708-10. 

This compound is prepared from N-butylethanolamine and nitric acid with acetic anhydride and a chloride source for catalysis. N-BuNENA is an energetic plasticizer for propellant formulations... 

Diazotization of cyclopropylamines in the presence of a chloride source is also a useful method for the preparation of some chlorocyclopropanes. When 1-aminocyclopropanecarboxylic acid was treated with nitrous acid in the presence of potassium chloride, 1-chlorocyclopropanecarb-oxylic acid (9) was isolated in 75% yield. Similarly, a modified Sandmeyer reaction of 7-ami-nocyclopropanoacenaphthylene (10) yielded 7-chlorocyclopropanoacenaphthylene (11). ... 

Fig. 7.18 Change in corrosion potential of type 304 stainless steel with time at 25 °C in 1.5 wt% ferric chloride. Source Ref 30...

Z)-Chloroalkenes. Ketones are stereoselectively converted into (Z)-chloroalkenes hy PhCOCl using Sc(OTf)3 as catalyst. Cyanuric chloride is the chloride source and dehydrating agent (for reverting PhCOOH into PhCOCl)." ... 

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