BENZOIC ETHER. 



BENZOIC GROUP. 



90 



BENZOIC ETHER. [BENZOIC ACID.] 



BENZOIC GROUP. A very numerous family of organic com- 

 pounds, constituting one of the groups of the benzole series [BENZOIC 

 SERIES], and containing the radical benzoyl, or its derivatives. In 

 addition to a number of substances, which will be found in their 

 alphabetical position, this group contains the following compounds : 



Benzoine ? (C I4 H a 2 ). The name benzoine is given to the solid sub- 

 stance obtained by the action of alcoholic caustic potash upon hydride 

 of benzoyl, or oil of bitter almonds (C I4 H 5 O 2 H), which contains hydro- 

 cyanic acid, or by the action of cyanide of potassium upon the pure 

 hydride of benzoyl. As hydride of benzoyl is most consistently to be 

 viewed as an aldehyde, so benzoine stands probably in the same relation 

 to hydride of benzoyl that metaldehyd does to vinic aldehyd. 



C, 4 H s O a H, hj-dride of benzoyl ; C,H 3 O 2 H, hydride of ethyl, or aldchj-d. 

 2(C 14 H S O.,H) benzoine ; 2(C 4 II 3 O.,H) metaldehyd. 



If the crude oil of bitter almonds contains a sufficient quantity of 

 hydrocyanic acid, it is quickly converted into a mass of crystalline 

 benzoine on being mixed with a solution of caustic potash in alcohol ; 

 and from this mass the pure benzoine is obtained by repeated crystal- 

 lisation from alcohol. If the oil of bitter almonds is too pure for this, 

 instead of caustic potash an alcoholic solution of cyanide of potassium is 

 employed, and the same process of purification adopted. The nature 

 of the action of the cyanogen in polunerising the hydride of benzoyl is 

 not understood. Benzoine melts at 248 Fahr., and distils at a higher 

 temperature without decomposition. It is insoluble in cold, slightly 

 soluble in hot water, diflicultly soluble in cold, readily soluble in 

 boiling alcohol. Benzoine is re-converted into hydride of benzoyl on 

 being passed through a red-hot tube. On heating benzoine in dry 

 chlorine two atoms of hydrogen are removed in combination with 

 chlorine, and benzile is formed. 



2(C 14 U.O,) + 2C1 = 2(C 14 H S 2 ) + 2HC1. 



Benzile. 



The same elimination of hydrogen and formation of benzile is 

 effected by gently heating the benzoine with fuming nitric acid : 

 Fused hydrate of potash determines the formation of benzoate of 

 potash ; hydrogen being liberated 



2(C,,II 6 O.,) + 2KOHO = 2(KOC lt H 5 O 3 ) + 4H, 



while alcoholic caustic potash on boiling, converts beuzoinc into 

 benzilic acid, which unites with the potash, hydrogen, as before, being 

 set at liberty 



J(C 14 H.O,) + KO HO = KOC, 8 n,,0 5 + 211. 



On bringing benzoine in contact with the chlorides of the oxygen 

 radicals benzoyl or othyl, hydrochloric acid is evolved, and the place 

 of the hydrogen, which is derived from the benzoine, is occupied by 

 the oxygen radical employed. These products which are solid crystal- 

 line bodies, arc freed from hydrochloric acid by being heated on a 

 water-bath and recrystallised from alcohol. 



C "?'H 3 O, } ' Aeel!>l lmzoine - 

 ' 



,'iyl (Cj.HjO.,). This oxygenous radical of the benzoyl series, 

 which stands in the same relation to benzoic acid that othyl (CjH.,0.,) 

 does to acetic acid, has never yet been obtained in the free state. For 

 benzile [BENZOINE], although having the same composition as ben- 

 zoyl, and like all hitherto isolated organic radicals having the double 

 atomic weight of the same radical when in combination, yet has 

 properties so different from those which we should expect from the 

 free radical, that it must be viewed as a body merely isomeric with 

 benzoyl. The compounds of benzoyl are of great historical interest, 

 inasmuch as their study first established the possibility of a group of 

 elements containing oxygen, playing the part of a compound radical, 

 that is, of an element. 



The oxide of benzoyl (C, .H,O,, 0) 2 , or anhydrous benzoic acid. [BEN- 

 ZOIC ACID; ANHYDRIDES.] 



Chloride of Benzoyl (C I4 H ? 0, Cl), U formed directly from the 

 hydride by passing dry chlorine into the latter, and warming as long 

 as hydrochloric acid is evolved, C,.H 5 0, H + 2C1 = C,,H 5 O 3 Cl + HC'l. 

 A better way consists in gently heating in a retort 3 parts by weight 

 of previously fused and coarsely pounded benzoate of soda with 1 part 

 of oxychloride of phosphorus, 3(NaO C,.H.0 3 ) + PO. ! C1 3 = 3(0,^,0, 

 3NaOPO., and rectifying the distillate at 385. Chloride of 



., . 



benzoyl is a colourless liquid of most penetrating odour and burning 

 taste. Specific gravity, 1'196 ; boiling point, 385; vapour density, 

 4'98J. It is converted gradually by cold, and quickly by boiling water 

 into benzoic acid (benzoate of water), and hydrochloric acid. With 

 alcohol the action is similar but more energetic, benzoate of ethyl being 

 formed. 



The chloride of bichlorobenzoyl, a body which stands in the same 

 relation to benzoyl as chloroform (CjHC'l,) does to formyl (CjH0 2 ),and 

 which may be called Morobenz (C 14 H 3 C1 2 C1) is formed by heating 

 equivalent quantities of chloride of benzoyl and pentachloride of phos- 

 phorus at 392 Fahr. in a sealed glass tube for several days. The tube 

 is then opened and the volatile portions expelled by a temperature of 



230 Fahr. The residue, after agitation with caustic potash, washing 

 with water, solution in alcohol and precipitation by water, constitutes 

 the pure chlorobenz, which is a yellowish transparent liquid, soluble in 

 ether and alcohol, but insoluble in water. It is not volatile without 

 decomposition. The body just described is the chloride of benzoyl, in 

 which the oxygen is replaced by chlorine. A body has been formed 

 also by a replacement of a part of the hydro'jen of the radical in chloride 

 of benzoyl by chlorine. This substance results from the action of 

 pentachloride of phosphorus upon chlorobenzoic acid [BEXZOIC ACID]. 

 On distilling the two together, and rectifying the distillate at 437, a 

 colourless transparent liquid is obtained, boiling at the above tempera- 



TT 



ture, and soluble in alcohol and ether. Its composition is C 14 p,*0 2 Cl, 



being the chloride of chlorobenzvyl. This substance dissolves in aqueous 

 ammonia, the solution depositing yellow needles of chlovobenzaniitie 



A body ideotypic with the chloride of chlorobenzoyl is the chloride of 



/ TT * 



nltrobetizoyl (C^jjjJ 0.,C1) prepared by the action of pentachloride of 



phosphorus upon uitrobenzoic acid [BENZOIC ACID]. The distillate 

 produced by heating together nitrobenzoic acid and pentachloride of 

 phosphorus is rectified, the latter portion being free from the oxychlo- 

 ride of phosphorus which is a by-product of the reaction, consists of the 

 chloride of nitrobenzoyl, which is washed with water, dried over chlo- 

 ride of calcium and distilled. It boils at 509. Chloride of nitro- 

 benzoyl gives a series of compounds prepisely. analogous to those 

 derived from chloride of bsnzoyl. 



Bromide of benzoyl (C, 4 H 3 2 Br). If hydride of benzoyl be mixed with 

 an excess of bromine, heat is evolved, hydrobromic acid liberated, and 

 bromide of benzoyl formed. On heating the product, the hydrobromic 

 acid is expelled along with the excess of bromine, and a half crystalline 

 mass is obtained of pure bromide of benzoyl : a body of an odour 

 similar to, but feebler than, that of the chloride. It is insoluble in, but 

 slightly decomposed by, water ; and soluble without decomposition iu 

 ether and alcohol. 



Iodide of benzoyl (C lt H 5 2 I) is formed by warming iodide of potas- 

 sium with chloride of benzoyl. When pure, iodide of benzoyl is 

 colourless ; it readily decomposes on heating, iodine being liberated. 

 Its behaviour to water and solvents is the same as that of the bromide. 



Cyanide of benzoyl (C 14 H 5 O 2 Cy). Is obtained as a colourless liquid 

 on rectifying the product produced by the distillation of equal equiva- 

 lents of chloride of benzoyl and cyanide of mercury. On standing, the 

 liquid solidifies ; it may then be washed with water to remove the 

 chloride of mercury, and pressed between bibulous paper. Cyanide of 

 benzoyl melts at 88 Fahr., and boils at 405 Fahr. It is slowly decom- 

 posed by water, readily by the alkalies ; in the latter case, benzoates 

 and cyanides are found. Nascent hydrogen converts it into hydride of 

 benzoyl and benzoine. 



Sulphide of benzoyl (C 14 H 3 2 S). Is a soft crystalline yellowish white 

 body, obtained by distilling chloride of benzoyl with sulphide of lead. 

 It is stable in its nature, and its properties have been little studied. 



Cyanide of sulphobenzoyl, improperly called sulphocyanide of beu- 

 zoyl, a body having the composition,C 14 H 5 S,j Cy, is obtained by mixing 

 ammonia, bisulphide of carbon, and hydride of benzoyl, and pressing 

 out the crystals which form iu the lower of the two layers of the 

 mixture. On washing the crystals with ether, pure cyanide of sulpho- 

 benzoyl is obtained. The reaction is as follows : C 14 H 5 0.,H + 3NH,-f 

 2(CS 2 ) = C 14 H 3 S 2 Cy + 2NH 4 S + 2 HO. The cyanide of s'ulphobenzoyl 

 is insoluble in water, but somewhat soluble in alcohol and ether. The 

 products of decomposition are little understood. 



Although benzoyl has not been obtained in combination with the 

 metals directly, yet a compound of it with an organic radical, namely, 

 phenyl, is known. This body, Benzoyl-plientil, also called Sen-one or 

 Jienzophenone, C^HjOjC^Hj is the acetone of benzoic acid. It is pre- 

 pared by the destructive distillation of benzoate of lime in presence of 

 about -f (l th of its weight of quicklime. The process is best conducted 

 in an iron mercury bottle. Besides benzone the distillate contains, 

 benzole, hydride of benzoyl, and other products ; that portion of the 

 distillate is collected which on rectification passes over between 599 

 and 617. This portion solidifies on cooling, and is purified by repeated 

 crystallisation from a mixture of alcohol and ether. Benzone melts at 

 115 Fahr., and boils at 599 Fahr. It is insoluble in water, soluble in 

 strong sulphuric and nitric acids without change. If, however, fum- 

 ing nitric acid be employed, the nitric acid eliminates two atoms of 

 hydrogen and binitro-benzone results. It is most probable that of the 

 two atoms of hydrogen removed, the one belonged to the phenyl, the 

 other to the benzoyl, and that the rational formula of binitro-benzone is 



It is prepared by wanning benzone with fuming nitric acid, and dis- 

 solving the semi-solid product (after washing) in ether. The binitro- 

 benzone crystallises from the ethereal solution as a yellowish white 

 crystalline powder. 



Bmvmitril. [PHENYL, CYANIDE OF.] 



The compounds of benzoyl formed upon the ammonia type are very 

 numerous. Those compound ammonias which contain beuzoyl in place 

 of hydrogen, do not combine so readily with the hydracids to form 



