Benzene addition compound with

The student should note that ketones in class (1), t.c., those having the >CO group in the side chain, will form additive compounds with sodium bisulphite only if this >CO group is not directly joined to the benzene ring acetophenone therefore will not form such compounds, whereas benzyl methyl ketone, CaHsCHjCOCH, will do so. Many quinones, particularly ortho quinones such as phenanthraquinone, form additive compounds with sodium bisulphite. 

If ethylene is treated with nitrating acid, nitroethyl nitrate, N02.CH2.CH20N02 is produced, as has already been mentioned. The nitroethyl alcohol which is first formed by addition of nitric acid is fixed by esterification, whereas the addition compound with HNOs which is first formed at the double bond of benzene is decomposed with elimination of H20 for reasons which have been mentioned repeatedly. This case is therefore analogous to the reactions of bromine with ethylene and with benzene (p. 106). 

Many aromatic hydrocarbons, for example, benzene, ethylbenzene, toluene, cymene and tetrahydronaphthalene, yield additive compounds.5 Such are also formed with liquid cyclic hydrocarbons in the absence of moisture and phenols, and use has been made of this fact to remove sulphur dioxide from a dry gas containing it.6 Additive compounds are also formed with methyl alcohol, thus CH30H.S02 and 2CH30H.S02, the existence of which has been demonstrated definitely by means of the freezing-point curve.7 The additive compound with camphor has already been mentioned (p. 109). 

Figure 14.29 shows the (solid + liquid) phase diagram for (benzene + hexafluoro-benzene). A congruently melting solid molecular addition compound with the formula QFU-CeFe ) is evident in this system.26 The rounded top of the freezing curve (solid line) for the addition compound results from almost complete dissociation of the addition compound in the liquid mixture. In other words, benzene and hexafluorobenzene act as independent molecular species in the liquid state and combine together as the addition compound only in the solid state. 

Benzene forms an addition compound with chlorine, CgHg C. The crystal structure is monoclinic, with two molecules per cell,... 

Vanadium(IV) oxy(acetylacetonate) is a blue to blue-green compound, crystallizing in the monoclinic system with refractive indexes of a, 1.520 0, 1.676 y, 1.739.7 The compound was originally believed to be a 1-hydrate but is now known to be anhydrous. It forms addition compounds with pyridine, methylamine, and other amines.8 Vanadium(IV) oxy(acetylacetonate) decomposes at elevated temperatures and has no definite melting point. The compound is soluble in ethanol, benzene, chloroform, and acetylacetone but is only moderately soluble in acetone or ethyl ether. 

Uranyl chloride is a bright yellow substance which crystallizes in the orthorhombic system. The compound is only slightly volatile in oxygen or chlorine below 500°, and volatility is appreciable only above 775°. It decomposes in vacuo above 450° to give chlorine and the oxides U02 and UgOg. Uranyl chloride is very hygroscopic and dissolves extensively in water. The compound is soluble in polar organic solvents such as acetone and the alcohols but does not dissolve in less polar solvents such as benzene. Its aqueous solutions are both thermally and photo-chemically unstable. A number of hydrates and addition compounds with halides and amines have been described. 

Crown ethers have recently been shown to form crystalline, strictly stoicheiometric addition compounds with hexasubstituted benzene derivatives, e.g. (94), which are suited for systematic investigations of intra- and inter-... 

Triethylphosphme forms a large number of addition compounds with metallic salts, the constitution of some of the compounds having given rise to considerable discussion. The derivatives are as follows From auric chloride—(C2H5)3P.AuCl or [AuP(C335)3]CL This results when an alcohol solution of the phosphine is treated with auric chloride at the ordinary temperature. It crystallises in colourless needles or prisms, melting with decomposition at 80° C., soluble m alcohol, ether, chloroform, benzene and acetic acid, sparingly soluble in warm water... 

Several possible commercial apphcations of adductive crystallization have been reported. For example, the system m-cresol-p-cresol forms two eutectics over the complete range of composition, and the separation of the pure components cannot be made by conventional crystallization. Savitt and Othmer (1952) described the separation of mixtures of these two components by the use of benzidine to form a sohd addition compound with p-cresol. Actually both m-cresol and p-cresol form addition compounds with benzidine, but the meta-compound melts at a lower temperature than the para-. If the process is carried out at an elevated temperature the formation of the meta- complex can be avoided. The method consists of adding benzidine to the meta-para- mixture at 110 °C. The /7-cresol benzidine crystallizes out, leaving the m-cresol in solution. The crystals are filtered off, washed with benzene to remove w-cresol, and the washed cake is distilled under reduced pressure to yield a 98 per cent pure i-cresol. 

Sulfonation with Sulfuric Acid and Sulfur Triozide. Various mechanisms for the reaction of aromatic hydrocarbons or aryl halides with sulfuric acid or with sulfur trioxide have been proposed. Since.the reaction is heterogeneous, it is not favorable for experimental study. Solvents that dissolve sulfuric acid or sulfur trioxide form addition compounds with the reagent hence any conclusion drawn from a homogene ous sulfonation might not be applicable to the ordinary sulfonation. One possibility is that an electrophilic reagent such as sulfur trioxide with its relatively positive sulfur atom or an ion such as HOaS" " in the case of sulfuric acid attacks the negative center of the polarized form of the hydrocarbon, as illustrated for benzene. 

The stability of the complex is also influenced by the second component of the addition compound. The number of aromatic nuclei in the molecule has a positive effect. For example, benzene does not form a stable addition compound with picric acid, but naphthalene gives a sufficiently stable compound. Substitution with a methyl, hydroxyl, or amino group has a positive effect on the stability of addition complexes, while the presence... 

Bisulphite addition compound. Shake 1 ml. of acetone with 0 5 ml. of a saturated solution of NaHS03. A white precipitate is formed, the mixture becoming warm and then, on cooling, almost solid. Acetophenone and benzophenone, having the >CO group directly joined to tlie benzene ring, do not respond to the test (p- 257). 

The soiution is aliowed to cool and the crystals of the P2P-bisulfite addition compound are then separated by vacuum filtration, washed with a little clean dH20 then washed with a couple hundred mLs of ether, DCM or benzene. The filter cake of MD-P2P-bisulfate is processed by scraping the crystals into a flask and then 300mL of either 20% sodium carbonate solution or 10% HCi soiution are added (HCI works best). The soiution is stirred for another 30 minutes during which time the MD-P2P-bisulfite complex will be busted up and the P2P will return to its happy oil form. The P2P is then taken up with ether, dried and removed of the solvent to give pure MD-P2P. Whaddya think of that ... 

Manske has isolated from several papaveraceous plants an alkaloid aurotensine (items 9, 19, 23, 44, 47, 48 list, pp. 170-3) which occius in rhombic plates, m.p. 128° [a]n — 69-9° and appears to be an addition compound of I- and di-scoulerine (Manske ). Its dimethyl ether caseanine item 10 list, p. 170), m.p. 115-6° (hydrated) or 142° (ex benzene) must be tetrahydropalmatine (p. 292) and casealutine, found with caseanine, was shown later by Manske to be i-isocorypalmine. 

An important property of aromatic hydrocarbons is that they are much more stable and less reactive than other unsaturated compounds. Benzene, for example, does not react with many of the reagents that react rapidly with alkenes. When reaction does take place, substitution rather than addition is observed. The Kekule formulas for benzene seem inconsistent with its low reactivity and with the fact that all of the C—C bonds in benzene are the sane length (140 pm). 

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