摘要:

Infrared spectra of polycrystalline K2CuCl4•2H2O at different degrees of deuteration were recorded, between 4000 and 300 cm−1, at temperatures from −160 to 90 °C. The spectra confirm the existence of only one crystallographically distinct type of water molecule in the structure, on sites of symmetryC2r. Vibrational coupling of the bending fundamentals of the water molecule has been analyzed in detail. It is shown that the existence and magnitude of such coupling may be used to predict, from the spectrum of a hydrate, the manner in which a water molecule participates in the crystal structure. The structure and the vibrational spectra of K2CuCl4•2H2O are compared with those of the closely related CuCl2•2H2O.

ISSN:0008-4042    

DOI:10.1139/v74-164

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The diene20synthesized by the aziridine rearrangement method was shown to add maleic anhydride with complete stereospecificity to yield the adduct21. The causes of this stereospecificity and its implications for the synthesis of denudatine type compounds are discussed.

ISSN:0008-4042    

DOI:10.1139/v74-165

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The kinetics of the nitrosation of pyrrolidine and proline have been investigated in buffer solutions of mildly acidic pH's in the temperature range 40–100 °C. The rate constants were determined and the enthalpy and the entropy of activation were calculated for both reactions. Examples are presented in which are estimated the maximum amounts of nitroso compounds formed under conditions relevant to meat processing.

ISSN:0008-4042    

DOI:10.1139/v74-166

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The coordinated imine groups of the Schiff's base – zinc complexes derived from various 2-substituted benzothiazolines are easily reduced with sodium borohydride to the corresponding amines. Removal of the metal ion from these reduced complexes yields the free ligands, providing a simple route to novel aminomercaptan chelating agents. Compounds of bi-, tri-, and tetradentate types were prepared in this manner.Evidence is given for a disproportionation of 2,2′-dimethyl-2,2′-bibenzothiazolinyl into 2-methylbenzothiazoline and 2-methylbenzothiazole in chloroform solution.

ISSN:0008-4042    

DOI:10.1139/v74-167

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The rates of detritiation of triphenlymethane, 9-phenylxanthene, fluorene, 9-ethylfluorene, 9-phenylfiuorene, and 2,3-benzofluorene have been measured in ethanolic dimethyl sulfoxide (DMSO) containing sodium ethoxide. When the logarithm of the ionization rate is plotted against the logarithm of the ionization rate of DMSO a straight line of near-to-unit slope is obtained in each case. There are significant differences, however, between relative ionization rates and equilibrium acidities.

ISSN:0008-4042    

DOI:10.1139/v74-168

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

In an attempt to prepare adamanto[1,2-d]oxazolidin-2-one (2), 2-adamantyl azidoformate was subjected to photolysis in cyclohexane. The main product8(yield 41%) is formed by intermolecular insertion of the nitrene in the solvent. The only other pure compound isolated (yield 15%) is a product of intermolecular insertion. The i.r. spectrum of the latter supports the presence of a five-membered cyclic carbamate. The fact that intermolecular insertion is the main reaction is unexpected in view of the results reported by others.

ISSN:0008-4042    

DOI:10.1139/v74-169

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The hydrolysis of triethyl phosphate in water and in 35% dioxane – 65% water has been examined. Hydrolysis in neutral water proceeds with a rate constant of 8.35 × 10−6s−1at 101°, ΔH* = 23.4 kcal/mol, ΔS* = −20 e.u., a solvent isotope effectof 1.3, C—O bond cleavage as shown by18O labeling, and no catalysis by 0.5 Msulfuric acid. These results are consistent with the BAL2 mechanism of hydrolysis and the same pathway is indicated for the reaction in neutral 35% dioxane –65% water. Perchloric acid catalyzes the reaction in dioxane–water with C—O bond cleavage in 0.904 Macid, ΔH* = 24.1 kcal/mol, ΔS* = −17 e.u., and the solvent isotope effectin 0.556 Macid. These results indicate that the AAL2 pathway of hydrolysis is followed under these conditions. The reactivity of triethyl phosphate is compared with that of ethyl acetate.

ISSN:0008-4042    

DOI:10.1139/v74-170

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

In attempts to uncover a relatively mild method for the oxidative degradation of humic substances, a humic and a fulvic acid were oxidized with peracetic acid at 40 °C for 8 days. The oxidation products were extracted into organic solvents, methylated, separated by column-, thin layer-, and preparative gas-chromatography, and identified by matching their mass and micro-i.r. spectra with those of authentic specimens.The major humic acid oxidation products were phenolic acids (isolated in fully methylated forms, 8.4%), benzenecarboxylic acids (as methyl esters, 16.0%), and aliphatic acids (as methyl esters, 3.4%). The fulvic acid yielded 11.5% phenolic compounds, 8.4% benzenecarboxylic acids (as methyl esters), and 2.6% aliphatic acids (as methyl esters). These data indicated a more phenolic character for the fulvic acid than for the humic acid. In addition, small amounts of 2-methyl-3,4-furandicarboxylic acid were tentatively identified as dimethyl esters among humic and fulvic acid oxidation products. As far as total yields of oxidation products were concerned, peracetic acid oxidation at 40 °C of untreated humic and fulvic acids compared favorably with permanganate oxidation of methylated humic materials at about 100 °C, but was more time consuming.The results of this and earlier oxidative degradation studies show that the oxidation of humic substances produces phenolic and benzenecarboxylic acids as major products in addition to smaller amounts of aliphatic dicarboxylic acids. Whether these products arise from more complex structures of lignin or microbial origin or whether they occur in the forms in which they were isolated but held together by hydrogen-bonding or Van der Waal's forces requires further investigation.

ISSN:0008-4042    

DOI:10.1139/v74-171

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Infrared spectra, in the range 20–400 cm−1, of thin polycrystalline films (at 80 °K) of iodine monobromide and the β-form of iodine monochloride have been recorded. For IBr, the intramolecular stretching region shows two peaks separated by 16 cm−1and shifted appreciably from the gas phase value, indicating strong intermolecular interactions. Four lattice modes are also observed and assigned in accordance with group theoretical predictions. For β-ICl the spectrum of the stretching region confirms the presence of two distinct molecules with different bond lengths. The complexity of the ICl structure prevents an assignment of the ten observed lattice absorptions.

ISSN:0008-4042    

DOI:10.1139/v74-172

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The nature of the species undergoing exchange and the role of the buffer anion in the medium are not known precisely from previous investigations on the isotopic exchange of rare earth metal ions with their EDTA complexes confined to acetate medium only.Using terbium-160 as radiotracer, the kinetics of self-exchange of Tb(III) in TbEDTA−has been studied in detail in 0.025Macetate buffer. The exchange has also been investigated in various other concentrations of acetate and phthalate buffer solutions, and also in benzoate buffer.In 0.025Mammonium acetate solution the rate of exchange (Rin mol l−1s−1) is expressed byover the concentration ranges employed. The predominant mode of exchange is the decomposition of the protonated complex TbHEDTA.It is concluded that the complex TbEDTA−is the only species undergoing exchange, although it is possible that mixed complexes formed between TbEDTA−and acetate ion may be present in the medium. Increasing charge on the buffer anion species accelerates the rate of exchange, while the effect of the buffer anion size is relatively insignificant. A small positive effect observed for the ionic strength on exchange has also been interpreted.

ISSN:0008-4042    

DOI:10.1139/v74-173

出版商:NRC Research Press    

年代:1974

数据来源: NRC