Phthalyl chloride

Treatment with PCI5 gives phthalyl chloride reduction with zinc and ethanoic acid or NaOH gives phthalide. Fusion with urea gives phthalimide. 

It IS by a similar process that alizaiin has been synthesised w ith the oliject of ascertaining its constitution (see Notes on Prep. 110, p. 316), When two molecules of phenol and one molecule of phthalic anhydride are heated together with cone, sulphuric acid, then phenolphthalein is formed (Baeyei). Its constitution has been determined by its synthesis from phthalyl chloride and benzene by means of the Friedel-Crafts leaction (see Notes on Piep. 100, p. 309). Phthalyl chloride and benzene yield in presence of AlCl., phthalophenone. 

Anthraquinone.—The constitution of anlhraqinnone is demed fiom various syntheses, such as the action of zinc dust on a mixture of phthalyl chloride and benzene, or by lieating benzoyl benzoic acid with II,Or,... 

Phthalyl Chloride (11,88) In nearly quantitative yields by the interaction of phthalic anhydride and thionyl chloride at 220° in the presence of very small amounts of zinc chloride. Kyrides, J. Am. Chem. Soc. 59, 206 (1937). 

The reaction of phthalyl chloride with benzene, leading to phthalo-phenone, the parent substance of the phthaleins ... 

Pure symmetrical o-phthalyl chloride cannot be obtained, even by recrystallization from carbon tetrachloride. A product melting at 16° may be obtained by distilling the unsymmetrical phthalyl chloride at atmospheric pressure. 

Symmetrical o-phthalyl chloride has been prepared by heating phthalic anhydride and phosphorus pentachloride in sealed tubes.1 This method is not convenient for the preparation of large quantities. 

Attempts have been made to prepare pure symmetrical o-phthalyl chloride by repeatedly heating the crude chloride,... 

Reaction XX. (a) Action of Metallic Zinc on a Mixture of an Aromatic Hydrocarbon and a Derivative of Phthalyl Chloride.—This is a method of synthesising anthraquinone and its derivatives, and hence a method of elucidating their structure, and also the structure of anthracene. Otherwise the method is not of importance, but it may be in the future, since anthraquinone is in great and increasing demand for the production of vat-dyestuffs, such as indanthrene phthalyl chloride can... 

The action of zinc in this case resembles that of anhydrous aluminium chloride in the Friedel-Crafts reaction. Phthalyl chloride here reacts in the s- form (cf. Reaction XX. (6) (vi.)). Both forms have been prepared (A., 392, 245 M., 40, 81). The s- form melts at 15°—16°, the as-at 88°—89°, while both boil at 275° at 720 mms. The s- form is converted into the as- by the action of aluminium chloride, while the reverse change is effected by the action of heat or of hydrogen chloride. (B., 55, 1305.)... 

With phthalyl chloride diphenylphthalide, important on account of its relation to the fluorescein dyes, is formed (B., 14, 1865). 

Comparing with Reaction XX. (a) it will be seen that phthalyl chloride is tautomeric. Succinyl chloride is also considered to be similarly tautomeric, a number of facts supporting this view. Unlike phthalyl chloride, however, it reacts in the symmetrical form. 

Physical Properties. The polymer structure of interest, arrived at after evaluating thoroughly various copolymer compositions, is derived from bisphenol-A, 4,4 -biphenyldisulfonyl chloride (BPDSC), and the mixed isomeric phthalyl chlorides (Figure 1). The composition and properties of this three-component copolymer can be varied over a wide range simply by varying the proportions of the three acid chlorides employed. 

Several dibasic acid halides are best prepared by this method from the readily available anhydrides. Thionyl chloride in the presence of a small amount of zinc chloride converts succinic and phthalic anhydrides to succinyl chloride (74%) and phthalyl chloride (86%), respectively. Phosphorus halides are used in similar preparations of phthalyl bromide (83%) and diphenic acid chloride (71%). ... 

Phthalyl chloride is obtained in almost quantitative yield by passing dry chlorine gas into molten thiophthalic anhydride, C,H (CO),S, at 245° until sulfur monochloride no longer distils. Thioanhydrides are made from the oxygen analogs and sodium sulfide. ... 

Phthalyl chloride, CjH4(COCl)j, converts butyric acid to butyryl chloride (92%) and maleic anhydride to fumaryl chloride (95%). 

Phthaloylperoxide (Phthalylsuperoxyd in Ger). (CgH404)x, mw (164.12)x, crysts, mp 133.5° with decomp, puffs off at about 136°. Insol in the usual organic solvents. Was prepd by von Pechmann and Vanino by shaking phthalyl-chloride with a soln of Na peroxide in 10% aq Na acetate under cooling. Explds on rapid heating or when brought into contact with coned sulfuric acid... 

Phthalimide.—Phthalic anhydride also yields other derivatives, viz., phthalimide and phthalyl chloride. When phthalic anhydride is treated with ammonia a compound is formed by replacement of the anhydride oxygen with the imide group, ( = NH),... 

Phthalyl Chloride.—When phthalic anhydride is treated with phosphorus pentachloride, in the proportion of one molecule of each, two chlorine atoms replace one oxygen atom and a compound is formed known as phthalyl chloride, an oily liquid, m.p. 0°, b.p. 275°. Two structures are possible for this chloride. 

It will be recalled that in the case of succinyl chloride both of these forms are obtained, but mostly the symmetrical (p. 282). Now from phthalic anhydride only one phthalyl chloride is obtained. This chloride acts like the unsymmetrical succinyl chloride, not like the symmetrical. The positive proof, however, that phthalyl chloride is the unsymmetrical compound is the following Sodium amalgam reduces phthalyl chloride by replacement of the chlorine with hydrogen. The compound formed is known as phthalide. This phthalide takes up water as anhydrides do and the product is hydroxy-methyl benzoic acid. 

From these relationships it is seen that phthalyl chloride must have the unsymmetrical formula. 

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