Hahdes acid halides

Plutonium reacts with hydrogen at high temperatures forming hydrides. With nitrogen, it forms nitrides, and with halogens, various plutonium hahdes form. Halide products also are obtained with halogen acids. Reactions with carbon monoxide yields plutonium carbides, whde with carbon dioxide, the products are both carbides and oxides. Such reactions occur only at high temperatures. 

Serine Carboxylic acids, acyl hahdes, sulfonyl halides, acid anhydride Acylation... 

Different metal chlorides unite with one another to form double lasts. Just as the acidic and basic oxides unite together to form oxy-salts, so do the halides of an electropositive element (or radicle) unite with a halide of a less positive element (heavy metal or metalloid) to form double halides. So far as is Imown the alkali chlorides do not unite with one another to form double salts, nor do the halides of the same natural group form compounds with one another, but compounds of the alkali chlorides with the chlorides of the more electronegative chlorides are known. A comparison of nearly 5CK) double halides has been made by H. L. Wells (1901).i He calls the one component—e.g. the alkali halide—the positive halide, and the other the negative halide. A. Werner calls the halide which plays the role of the basic oxide, the basic halide, and the other, the acid halide. A great many of the simple types of the double salts predominate. Writing the number of molecules of the positive hahde first, and the negative halide second, salts of the 2 1 and 1 1 ratios cover about 70 per cent, of the list of known double halides, and 4 1, 3 1, 3 2, 2 3, and 1 2 represent over 25 per cent. Two halides sometimes unite in several proportions—for instance, six caesium mercuric halides have been reported where... 

The mechanism of the Ni catalyzed carbonylation is depicted in Scheme 1.5 [17]. Ni(CO)4 is formed from various Ni precursors by a reductive reaction with CO. The hahde ions are important since they are the source of HX that can be oxidatively added to Ni(CO)4, forming HNi(C02)X. The latter reacts with olefin in an anti-Markovnikov way, giving the hnear alkyl-Ni species. The insertion of CO into the alkyl-Ni bond forms the acyl-Ni complex that decomposes under reductive elimination into the corresponding acid halide and Ni(CO)4. The former reacts with the nucleophile so that the product is set free and HX is regenerated. 

Acid halides are named as derivatives of carboxyhc acids by replacing the suffix ic acid with yl hahde ... 

As we have mentioned, acid hahdes are the most reactive of the carboxylic acid derivatives, becanse they produce the most stable leaving gronps. Therefore, we can prepare any of the other carboxylic acid derivatives from acid hahdes. So, it is critical that you know how to make an acid halide. It is very common to encounter a synthesis problem where you will need to make an acid hahde at some point in the synthesis. 

The carboxylic acid is first converted into an acid halide, which is then converted into an ester. But this begs the question can we achieve the desired transformation in one step That is, can we convert a carboxyhc acid into an ester in just one step, avoiding the need to prepare an acid hahde If we simply try to mix an alcohol and a carboxylic acid, we do not observe a reaction ... 

If we want to halogenate the alpha position of a carboxylic acid, it is possible, but it will require some extra steps. First, we must convert the carboxyhc acid into an acid halide. We do this because the enol of an acid halide will rapidly attack a halogen. Then, in the end, we just convert the acid hahde back into a carboxylic acid ... 

Notice the reagents that we used. We saw the reagent in the first reaction (Br2 and some mild acid— to halogenate a ketone). But to halogenate a carboxyhc acid, we use a different set of reagents. We use Br2 and PBrs, followed by H2O. The function of Br2 and PBrs is to make the acid halide, form the enol, and then have the enol attack Br2. Then, water is used in the last step to convert the acid hahde back into a carboxyhc acid. 

Acyl compounds (Section 17.1) A compound containing the group (R—C=0)—, usually derived from a carboxylic acid, such as an ester, acid halide (acyl hahde), amide, or carboxylic acid anhydride. 

Reaction with Alkyl Halide. The active methylene group of an Al-acylamino-malonic acid ester or Ai-acylamino cyanoacetic acid ester condenses readily with primary alkyl hahdes. 

Rhodium catalyzed carbonylations of olefins and methanol can be operated in the absence of an alkyl iodide or hydrogen iodide if the carbonylation is operated in the presence of iodide-based ionic liquids. In this chapter, we will describe the historical development of these non-alkyl halide containing processes beginning with the carbonylation of ethylene to propionic acid in which the omission of alkyl hahde led to an improvement in the selectivity. We will further describe extension of the nonalkyl halide based carbonylation to the carbonylation of MeOH (producing acetic acid) in both a batch and continuous mode of operation. In the continuous mode, the best ionic liquids for carbonylation of MeOH were based on pyridinium and polyalkylated pyridinium iodide derivatives. Removing the highly toxic alkyl halide represents safer, potentially lower cost, process with less complex product purification. 

Recently several pubhcations have examined replacing aqueous solvents with ionic liquids. Since simple and complex sugars are soluble in many imidazolium hahdes, water is not required as a co-solvent and degradation of HMF is minimal. Lansalot-Matras et al. reported on the dehydration of fmctose in imidazolium ionic liquids using acid catalyst (6). Moreau et al. reported that l-H-3-methylimidazolium chloride has sufficient acidity to operate without added acid (7). And we reported that a 0.5 wt% loading (6 mole% compared to substrate) of many metal halides in 1-ethyl-3-methylimidazohum chloride ([EMIM]C1) result in catalytically active materials particularly useful for dehydration reactions (8). 

Holmium is obtained from monazite, bastnasite and other rare-earth minerals as a by-product during recovery of dysprosium, thulium and other rare-earth metals. The recovery steps in production of all lanthanide elements are very similar. These involve breaking up ores by treatment with hot concentrated sulfuric acid or by caustic fusion separation of rare-earths by ion-exchange processes conversion to halide salts and reduction of the hahde(s) to metal (See Dysprosium, Gadolinium and Erbium). 

Hydrogen cyanide (Table 15.1) is a colorless, flammable liquid or gas that boils at 25.7°C and freezes at minus 13.2°C. The gas rarely occurs in nature, is lighter than air, and diffuses rapidly. It is usually prepared commercially from ammonia and methane at elevated temperatures with a platinum catalyst. It is miscible with water and alcohol, but is only shghtly soluble in ether. In water, HCN is a weak acid with the ratio of HCN to CN- about 100 at pH 7.2, 10 at pH 8.2, and 1 at pH 9.2. HCN can dissociate into H+ and CN. Cyanide ion, or free cyanide ion, refers to the anion CN derived from hydrocyanic acid in solution, in equilibrium with simple or complexed cyanide molecules. Cyanide ions resemble hahde ions in several ways and are sometimes referred to as pseudohahde ions. For example, silver cyanide is almost insoluble in water, as are silver halides. Cyanide ions also form stable complexes with many metals. 

The sttuctures of organoaluminum halides R AlXs are dominated by dimeric structures with AI2X2 four-membered rings for X = Cl, Br, and I. Unlike the aluminum alkyls, these hahde bridges are electron-precise and result from intermolecular Lewis acid-base complexation. These dimers do dissociate and readily react with Lewis bases, but the enthalpies of dissociation are higher than those for the aluminum alkyls. In many cases, the strength of the association is sufficient that dimers are observed in the gas phase. 

Some liquid covalent halides can act as nonaqueous solvents " based on Lewis acid-base behavior, according to the donor-acceptor definition. The self-dissociated ions consist of a cation formed by subtraction of a hahde ion from the neutral compound, while the anion is formed by its addition (equation 24). Salts derived from such covalent halides can be considered as titration products of the parent acidic and basic compounds (equations 25 and 26). In such cases, both the cation and the anion usually possess a stable coordination number with a high geometrical symmetry. 

The nitryl halides (C2 symmetry) are planar in analogy to the isoelectronic COs. The gas phase and solid-state structures for CINO2 both show covalently bound molecules (see Table 40). In contrast to the nitrosyl hahdes, the halogen-nitrogen bond distances in the gas phase and in the solid state are similar. The nitryl halides NO2F and NO2CI are the mixed anhydrides of nitric acid and hydrofluoric or hydrochloric acid, respectively. 

The synthesis can be extended to the preparation of ketones in six distinct ways. " These include quenching 180 with a second alkyl halide (R X) rather than acetic acid omitting PPhs with first RX and then adding the second, R X treatment with RX in the presence of CO, followed by treatment with R X treatment with an acyl halide followed by treatment with an alkyl hahde or an epoxide, gives an a,p-unsaturated ketone. The final variations involve reaction of alkyl halides or tosylates with Na2Fe(CO)4 in the presence of ethylene to give alkyl ethyl ketones when 1,4-dihalides are used, five-mem-... 

Several methods, all based on carbon monoxide or metal carbonyls, have been developed for converting an alkyl halide to a carboxylic acid or an acid derivative with the chain extended by one carbon. When an alkyl hahde is treated with SbCls—SO2 at —70°C, it dissociates into the corresponding carbocation (p. 236). If carbon monoxide and an alcohol are present, a carboxylic ester is formed by the following route ... 

Still another method for the conversion of halides to acid derivatives makes use of Na2pe(CO)4. As described in 10-76, primary and secondary alkyl hahdes and tosylates react with this reagent to give the ion RFe(CO)4 or, if CO is present, the ion RCOFe(CO)4. Treatment of RFe(CO)4 or RCOFe(CO)4 with oxygen or sodium hypochlorite gives, after hydrolysis, a carboxylic acid. " Alternatively, RFe(CO)4 or RCOFe(CO)4 reacts with a halogen (e.g., I2) in the presence of an... 

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