Metal phenolates

In the case of bromomagnesium 2-ferf-butylphenolate and different acyl chlorides, the phenol oxygen competes with the ortho-carhon, as previously mentioned, affording a mixture of esters and ortho-ketones. However, the electron-withdrawing power of the group at the a-position 

From a synthetic point of view, the process can be efficiently applied to the preparation of a large variety of ortho-hydroxyaryl ketones, as summarized in Table 5.1. Results from Table 5.1 are a proof of the powerful metal-template effect in promoting ortho-regioselective electrophilic acylation of phenol substrates. 

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Ullman reaction The synthesis of diaryls by the condensation of aromatic halides with themselves or other aromatic halides, with the concomitant removal of halogens by a metal, e.g. copper powder thus bromobenzene gives diphenyl. The reaction may be extended to the preparation of diaryl ethers and diaryl thio-ethers by coupling a metal phenolate with an aryl halide. 

Amongst the catalysts used or the polymerisation-trimerisation reactions are alkali metal phenolates, alcoholates and carboxylates and compounds containing o-(dimethylaminomethyl)phenol subgroups. Fluorocarbons such as trichloro-fluoromethanes are used as the sole blowing agents in the absence of any isocyanate-water reaction. 

No chlorides, volatile ingredients, heavy metals, phenols... 

These bulky terphenolate ligands have proved useful in the prevention of cyclometallation of the ort/zo-substituents146 in early-transition-metal phenolates. The bulky raeta-substituents prevent the rotation of the ortho-phenyl ring from becoming coplanar with the central phenoxide core, which is a requirement for C-H bond activation. 

Chlorinated rubber is also an effective bonding agent. It can be used for bonding neoprene, nitrile and natural rubbers to metals. Phenol formaldehyde resins have been used alone or in conjunction with chlorinated rubbers, but curing time is lengthy. 

Application of metal hydroxides is especially fruitful for the preparation of metal phenolates as the latter are exceptionally stable to hydrolysis. Reactions can be performed in alcohols, benzene, water or melted phenols [1644],... 

Phenoxide anions are prepared simply by adding the phenol to an aqueous solution of sodium hydroxide or potassium hydroxide. There is no need to use sodium or potassium metal. Phenol was once called carbolic acid because of its ability to neutralize common bases. 

Bigi, F., Maggi, R., Sartori, G., Casnati, G., Bocelli, G. Template Houben-Hoesch reaction on metal phenolates. Synthesis of aromatic ketones, nitriles and amides. Crystal structure of dichloro[2-(1-imino-2,2,2-trichloroethyl)-4-methoxyphenoxido-0,N]boron. Gazz. Chim. Ital. 

Scheme 4 shows the ionic substitution of a phenol by a metal phenolate compound, by a concerted mechanism. Although similar to Scheme 3, a phenoxonium ion is avoided, with probable energetic advantages thallium(III) oxidations of phenols may follow such a path. 

FIGURE 26. Selected B3LYP/6-311++G(d,p) optimized bond lengths (A) of some alkali metal phenolates in their ground singlet state... 

Figure 6.10 Group I and II metal phenolates with 2,6-dibenzylphenolate ligands. Oxygenated solvents are also co-ordinated to the metal centers.

Various of the classes of molecules described above are amenable to metal ion complexation. 2,6-Dibenzylphenols have been employed in the preparation of group I and II metal phenolates (Figure 6.10). as well as lanthanoid aryloxides. ... 

Watkinson [1988] lists some surfactants used for their dispersing action in organic liquids. He includes amongst them organic and metal sulphonates metal phenolates metal dialkyl dithiophosphates sodium dialkyl sulphosuccinates polyoxyethylene alkyl and alicyclic amines monethanol ammonium phosphate salts co-polymers of N-substituted formamide fatty acid phosphates... 

An alternative [25] uses the addition of o-metalated phenolic ethers 12 to alkoxymethylene malonic ester as a first step. Treatment with acid is followed by removal of the phenolic protective group, lactoniziation and ROH elimination to give the ester 13 ... 

The waste water can contain undissolved and dissolved heavy metals, phenols and cyanides. The treatment needs to be adapted to the type of pollutants. 

The syntheses of mono- and dicarboxylic acids via ionic reaction steps starting from butadiene and carbon dioxide are well studied reactions. For instance, Cg-, C13- and C-]7-monocarboxylic acids as well as Ciq-dicarboxylic acids can be prepared in the presence of sodium [72,73]. Also metal phenolates catalyze the synthesis of acyclic dicarboxylic acids. When sodium phenolate is dissolved in dimethylformamide and CO2 and butadiene are added and reacted 3 hrs at 50 C, muconic acid is formed in 81 % yield. Hydrogenation of muconic acid leads to adipic acid [741. In a similar reaction, Thiele s acid, that is tricyclo-[5.2.1.02 6]deca-3.8-diene-4.9-dicarboxylic acid, is formed by two moles of cyclopentadiene and two moles of carbon dioxide [79 (Equation 13). 

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