Cuprous chloride, catalyst

In the presence of a pyridine-cuprous chloride catalyst, the following polymerization occurs ... 

At one time, the only commercial route to 2-chloro-1,3-butadiene (chloroprene), the monomer for neoprene, was from acetylene (see Elastomers, synthetic). In the United States, Du Pont operated two plants in which acetylene was dimeri2ed to vinylacetylene with a cuprous chloride catalyst and the vinyl-acetylene reacted with hydrogen chloride to give 2-chloro-1,3-butadiene. This process was replaced in 1970 with a butadiene-based process in which butadiene is chlorinated and dehydrochlorinated to yield the desired product (see Chlorocarbonsandchlorohydrocarbons). 

Exactly the same result was obtained when the homopolymers were oxidized at — 25°C with a N,N,N, N -tetraethylethylenediamine-cuprous chloride catalyst, conditions which have been reported to cause coupling of DMP homopolymers solely by rearrangement (14). The NMR spectrum of this polymer is shown in Figure 3, together with the spectra of a mixture of homopolymers and of a random copolymer formed by simultaneous oxidation of the monomers. Apparently, dissociation and redistribution occur often enough to determine the structure of the product in this system, even under conditions that favor coupling of polymer molecules by the rearrangement mechanism. 

Oxidation of Mixtures of Monomers. The method most likely to yield random copolymers of DMP and DPP is the simultaneous oxidation of a mixture of the two phenols, although this procedure may present problems because of the great difference in reactivity of the two phenols. The production of high molecular weight homopolymer from DPP is reported to require both a very active catalyst, such as tetramethylbutane-diamine-cuprous bromide, and high temperature, conditions which favor carbon-carbon coupling and diphenoquinone formation (Reaction 2) from DMP (II). With the less active pyridine-cuprous chloride catalyst at 25 °C the rate of reaction of DMP, as measured by the rate of oxygen... 

Figure 1. Disappearance of monomers on oxidation of equimolar mixture of dimethylphenol and diphenylphenol (pyridine-cuprous chloride catalyst)...

Tn 1959 Hay (19) reported that 2,6-xylenol reacts with oxygen in the presence of a pyridine-cuprous chloride catalyst to yield a high molecular weight poly(l,4-arylene oxide) (Reaction 1). 

Alkynylmagnesium halides are less basic than the alkali metal acetylides and therefore can be applied to sensitive alkylating agents. In contrast to the alkali metal acetylides they do not react with saturated primary halides. On the other hand, they do react with allylic, propargylic and benzylic halides, but only in the presence of cuprous chloride catalysts. They also react with a-haloethers (e.g. equation 136)" . 

Derivation (1) From propylene oxygen and ammonia with either bismuth phosphomolybdate or a uranium-based compound as catalysts (2) addition of hydrogen cyanide to acetylene with cuprous chloride catalyst (3) dehydration of ethylene cyanohydrin. 

Derivation (1) Reaction of adipic acid and ammonia (catalytic vapor phase) to yield adiponitrile, followed by liquid-phase catalytic hydrogenation. (2) Chlorination of butadiene followed by reaction with sodium cyanide (cuprous chloride catalyst) to 1,4-dicyanobutylene and hydrogenation. 

The synthesis of benzaldehyde from benzene poses a problem because formyl chloride, the acyl halide required for the reaction, is unstable and cannot be purchased. Formyl chloride can be prepared, however, by means of the Gatterman-Koch formyla-tion reaction. This reaction uses a high-pressure mixture of carbon monoxide and HCl to generate formyl chloride, along with an aluminum chloride-cuprous chloride catalyst to carry out the acylation reaction. 

Another reaction of significance involving methanol is the direct synthesis of dimethyl carbonate (DMC) by carbonylation of methanol with CO which offers a potentially green chemical replacement for phosgene which is used for polymer production and other processes. The direct synthesis of dimethyl carbonate has been pursued over a variety of carbon supported cuprous chloride catalysts, but these catalysts deactivate due to loss of chloride and as such require reactivation by drying and contact with gaseous HCl. King et discovered that the chloride is not necessary to catal-... 

Another early development of the Bart procedure was the use of diazonium fluoroborates instead of the more usual chlorides 144, 145). Subsequently Doak and Freedman 146) found that dry diazonium fluoroborates react with arsenic trichloride in dry ethanol to give both arsonic and arsinic acids. Under these conditions maximum yields of the arsonic acid are obtained using a cuprous chloride catalyst. In 80% ethanol quite high yields of the arsinic add are obtained using cuprous bromide as catalyst. These workers later found that fluorozincates and fluorosilicates give similar results 147). 

The success of the Bart reaction when applied to nuclear- substituted anilines is often much affected by the pH of the reaction-mixture. Furthermore, the yields obtained from some m-substituted anilines, which under the normal conditions are usually low, arc considerably increased by the modifications introduced by Scheller, and by Doak, in which the diazotisation is carried out in ethanolic solution followed by reaction with arsenic trichloride in the presence of a cuprous chloride or bromide catalyst. 

Allyl Chloride. Comparatively poor yields are obtained by the zinc chloride - hydrochloric acid method, but the following procedure, which employs cuprous chloride as a catalyst, gives a yield of over 90 per cent. Place 100 ml. of allyl alcohol (Section 111,140), 150 ml. of concentrated hydrochloric acid and 2 g. of freshly prepared cuprous chloride (Section II,50,i one tenth scale) in a 750 ml. round-bottomed flask equipped with a reflux condenser. Cool the flask in ice and add 50 ml. of concen trated sulphuric acid dropwise through the condenser with frequent shaking of the flask. A little hydrogen chloride may be evolved towards the end of the reaction. Allow the turbid liquid to stand for 30 minutes in order to complete the separation of the allyl chloride. Remove the upper layer, wash it with twice its volume of water, and dry over anhydrous calcium chloride. Distil the allyl chloride passes over at 46-47°. 

The following mechanism of the Sandmeyer reaction has been proposed as a result of a kinetic study, and incidentally accounts for the formation of the azu compounds as by-products. The catalyst is the CuCl ion produced in the dissolution of cuprous chloride in the chloride solution ... 

By passing a mixture of carbon monoxide and hydrogen chloride into the aromatic hydrocarbon in the presence of a mixture of cuprous chloride and aluminium chloride which acts as a catalyst (Gattermann - Koch reaction). The mixture of gases probably reacts as the equivalent of the unisolated acid chloride of formic acid (formyl chloride) ... 

Using cuprous chloride as catalyst, hydrogen chloride adds to acetylene, giving 2-chloro-1,3-butadiene [126-99-8], chloroprene, C H Cl, the monomer for neoprene mbber. 

Heating with cuprous chloride in aqueous hydrochloric acid isomerizes 2-butene-l,4-diol to 3-butene-l,2-diol (98)] Various hydrogen-transfer catalysts isomerize it to 4-hydroxybutyraldehyde [25714-71-0] (99), acetals of which are found as impurities in commercial butanediol and... 

The reaction occurs bypassing HCN and a 10 1 excess of acetylene into dilute hydrochloric acid at 80°C in the presence of cuprous chloride as the catalyst. 

Sta.rting from Phenol. Phenol can be selectively oxidized into -benzoquinone with oxygen. The reaction is catalyzed by cuprous chloride. At low catalyst concentration, the principal drawback of this method is the high pressure of oxygen that is required, leading to difficult safety procedures. It appears that a high concentration of the catalyst (50% of Cu(I)—phenol) allows the reaction to proceed at atmospheric pressure (58). 

Dimethyl carbonate [616-38-6] and dimethyl oxalate [553-90-2] are both obtained from carbon monoxide, oxygen, and methanol at 363 K and 10 MPa (100 atm) or less. The choice of catalyst is critical cuprous chloride (66) gives the carbonate (eq. 20) a palladium chloride—copper chloride mixture (67,68) gives the oxalate, (eq. 21). Anhydrous conditions should be maintained by removing product water to minimize the formation of by-product carbon dioxide. 

Chloro-l,2-butadiene [25790-55-0] is mainly of historical iaterest (2). It is formed from vinylacetylene and HCl ia the absence of an isomerization catalyst. In the usual process for chloroprene usiag cuprous chloride, a portion of this isomer may be formed initially and then isomerize, but most of the chloroprene is apparently formed directly by the addition. 

Many catalysts are used to effect the reaction, such as zinc chloride on pumice, cuprous chloride, and ignited alumina gel. The reaction conditions are 350°C at nearly atmospheric pressure. The yield is approximately 95%. 

Cuprous -butylmercaptide, 42,22 Cuprous chloride as catalyst for 1,4 addition of Grignard reagents to ar,0-unsaturated esters, 41, 63 Cyanoacetic acid, tert-butyl ester, 41, 5... 

Reaction of bisphenol with chloronitroaromatic compounds was generally performed in dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) at reflux using K2C03 as a base.108 109 It is possible to achieve this condensation in Ullmann s conditions by using a cuprous chloride or iodide-pyridine system as a catalyst when this reaction is performed with deactivated aromatic compounds, it gives too poor yields110 ultrasounds can dramatically improve yields without solvent.111... 

The Ullman reaction has long been known as a method for the synthesis of aromatic ethers by the reaction of a phenol with an aromatic halide in the presence of a copper compound as a catalyst. It is a variation on the nucleophilic substitution reaction since a phenolic salt reacts with the halide. Nonactivated aromatic halides can be used in the synthesis of poly(arylene edier)s, dius providing a way of obtaining structures not available by the conventional nucleophilic route. The ease of halogen displacement was found to be the reverse of that observed for activated nucleophilic substitution reaction, that is, I > Br > Cl F. The polymerizations are conducted in benzophenone with a cuprous chloride-pyridine complex as a catalyst. Bromine compounds are the favored reactants.53,124 127 Poly(arylene ether)s have been prepared by Ullman coupling of bisphenols and... 

When 2-methoxy-l,6-methano[10]annulene 32 was subjected to a cyclopropana-tion with diazomethane and cuprous chloride as catalyst reaction occurred preferentially at the 5,6-, 6,7- and/or 1,10-bonds and the adducts spontaneously underwent disrotatory opening yielding the corresponding methoxybicyclo[5.4.1]dodecapen-taenes. Hydride abstraction with triphenylmethyl fluoroborate was performed on the mixture and the ions 33 and 34 so produced were treated with dilute aqueous potassium hydroxide. The annulenones 13 and 14 were then separated by chromatography. 

The orientation of the addition of HC1 to a variety of halogen-substituted 1,3-butadienes has been extensively studied under preparative conditions39-43. The results are given in Table 3. No significant polymerization was observed and the products were in all cases those resulting from a 1 1 addition process. The regiochemistry control by the position of the chlorine atom was quite versatile. A Cl at C(l) favored formation of the 4,3-adduct whereas with Cl on C(2) the 1,4-adduct predominated. The competition between substitution by chlorine and methyl attenuated but did not markedly modify this orientation. However, all these reactions were quite slow and took from 5 to 10 h, even in the presence of a catalyst (mostly cuprous chloride). Therefore, product... 

There are a few reports of poly(naphthalene) thin films. Yoshino and co-workers. used electrochemical polymerization to obtain poly(2,6-naphthalene) film from a solution of naphthalene and nitrobenzene with a composite electrolyte of copper(II) chloride and lithium hexafluoroarsenate. Zotti and co-workers prepared poly( 1,4-naphthalene) film by anionic coupling of naphthalene on. platinum or glassy carbon electrodes with tetrabutylammonium tetrafluoroborate as an electrolyte in anhydrous acetonitrile and 1,2-dichloroethane. Recently, Hara and Toshima prepared a purple-colored poly( 1,4-naphthalene) film by electrochemical polymerization of naphthalene using a mixed electrolyte of aluminum chloride and cuprous chloride. Although the film was contaminated with the electrolyte, the polymer had very high thermal stability (decomposition temperature of 546°C). The only catalyst-free poly(naphthalene) which utilized a unique chemistry, Bergman s cycloaromatization, was obtained by Tour and co-workers recently (vide infra). 

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