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!iBSl'1<.4C.l', .I hc ratio of isomeric bispcrchloratomcrc~~ribenze~~es obtairietl from the monomercurial ancl mercuric perchloratc in perchloric acicl varies slightly with concentration of the acid, but is prepondera~~tly meta. Howe\.er, more para than meta isomcr is o b t a i~~e d under conditions \\here the para isomer is insoluble ill thc s~~s t c~n .This indicates a mobile equilibri~~m among the isomers, which is found to estencl to all of the polymercuration p r o d~~c t s .The postulated intermediate for the equilibratio~~, which is 1,2,4-triclilorato~~iercuribenzene, is inclicated by the isolation of the similarly orie~~tecl 1,2,4,5-percliloratomercuritetral;ie1ze1ie. i\lthough nolle of the ortho-diperrhlorato~nerc~~ribe~~zene can be found fro111 this reaction in perchloric acicl, it is the principal isomer \\hen phenylmercuric acetate is acetos~~mercurated neat.

Alternative hypotheses can account for the ;'ield of more than one equivalent of Cyclonite frorn hexarnine when the Bachmann rcagcnts. ammonium nilrate, nitric acid, and acetic anhydride are used. In the nitrolysis, evidence for a stepwise synthesis from unit fragments is presented as the enhanced yield rvhen methylencdinitramine is added rvith paraform to ammonium nitrate and acetic anhydride according to the Schiessler-Ross method for Cyclonite synthesis.Horvever, this evidence is discounted becanse the expected b-v-prodLrct, i,S-diacetoxy-2,4-dinitro-2,4-diazapentane is not found. Alternatively it is believed that the Bachmann reaction is actualll' a combination of the direct nitroll'sis of hexamine r'vith nilric acid, concurrent rvith a resynthesis of hexamine frorlr the fragments prodrrccd b1'thc nitrolysi.. On rhis hasi. all l,y-products from lhe hexamethylenetetramine nitroll.sis must be accounted as degradation products of heramethlrlenetet'ramine and not capable of synthesis from unit frafrncnts like formaldehyde, ammonia, and acetic acid. No exception has been foLrnd; the addition of acylamides to the Bachmann reaction mixture increases the yield of two by-products, 1-ac1'l-3,S-dinitro-1,3,S-triazacyclohexane and 7-acyl-3,5,7trinitro-1,3,5,7-tetrazacvclooctane. It has been shown that these can be formed only from degradation prodncts of hexamethl'lenetetramine such as 1,S-diaceto-3,7-endomethylene-1,3,5,7-tetrazacyclooctane and acetaminomethylhexamethyienetetramine nitrate.When ammonium nitrate is used togetl-rer with nitric acid for the nitrolysis of hexamine in acetic anh-vdride, yields of Cyclonite are obtained which are greater than might be expected if one mole of hexamine were converted to one moie of the explosive (2). This process therefore differs from the Hale method by which hexamine is nitrolyzed in nitric acid alone. Yields from the latter reaction are always less than 100/6 on the 1 : 1 moiar basis (13). It also differs from the Ross-Schiessler process r,vhich employs formaldehyde and ammonium nitrate in acetic anhydride arld gives yields of 50 to 600/6 on the formaldehyde basis (18). The name that Bachmann has applied to his method (The Combination Frocess) implies that it includes both the Hale and the R oss-Schiessler reactions.According to this implication, hexamine first reacts with the nitric acid to form C1'clonite and fragments involving formaldehyde. These fragments have to recombine in some manner to provide a cyclic structure from which more Cyclonite can be formed. The recombination would, according to this reasoning, take place by the reaction through which Ross and Schiessler obtained Cyclonite. L Manuscript rece,iaed, Nouember 16, 1948. Contribution from the Chemi.cal Laboratory, Un.iaers'ity of Toronto, Toronto, Ontario. Can. J. Res. Downloaded from www.nrcresearchpress.com by MICHIGAN STATE UNIVERSITY on 03/10/15 For personal use only. Can. J. Res. Downloaded from www.nrcresearchpress.com by MICHIGAN STATE UNIVERSITY on 03/10/15 For personal use only. Can. J. Res. Downloa...

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Reactions of the complex [Ir(CO),CI,EtJ, with phosphorus ligands [L = PMe,Ph, PMePh,, P(OMe),, P(OMe),Ph, and P(OMe)Ph,] yield complexes [Ir(CO) L,CI,(COEt)] which subsequently rearrange in solution to a more stable isomeric form. The rearrangement is inhibited by the presence of free ligand L and kinetic data support a mechanism in which a five-co-ordinate intermediate (formed by loss of L from the less stable isomer) rearranges to a second intermediate. The latter then recombines with L to produce the more stable isomer. The reason for the exclusive formation of the less stable isomer of [Ir(CO)L,CI,(COEt)] from [Ir(CO),C12Et], is discussed in the context of the findings for the rearrangement reaction and a mechanism is proposed which is based on the large mns-effect of the propionyl iigand.