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84. , , : mainly, largely, markedly, readily, easily, accurately, slowly, gradually, closely, effectively, immediately, reversibly, exclusively, satisfactorily, normally, unequivocally, unambiguously, tentatively, virtually.

, .

:

In other cases, where some of the products do not crystallise easily, these could not be isolated.

Osmium pentafluoride melts at 70 to a green, viscous liquid which does not easily recrystallise. The liquid changes colour reversibly as the temperature is raised and at the boiling point (233)


is bright blue. Osmium pentafluoride can be handled and stored in glass under rigorously dry conditions. This cannot readily be achieved without introducing steps the chemistry of which cannot be visualised in detail. Analytical results prove that reduction occurs more readily in 24n- than in!6n-sulphuric acid. Their susceptibilities obey a Curie law quite closely. The liquids selected do not follow the principle of corresponding states accurately and it is concluded that their intermolecular forces are not conformal. The pronounced effect of additions of acetaldehyde shows it to give more vigorous branching than crotonaldehyde despite the fact that radical attack takes place preferentially on the latter. In another experiment, ammonia and ammonium chloride were added and the ammonia was immediately removed at low temperature to minimise ammonolysis of the aminoborine. At room temperature, the solid gradually lost hydrogen. As is to be expected, this effect is displayed most markedly by the strongest acid used. The ultraviolet and infrared spectra of ocotine are closely related to those of sepeerine and rodiasine. The group is found to consist of molecules all of which are effectively spherical. It is virtually identical with the spectrum given by a solution of acetophenone and m-dinitrobenzene in alkali of the same concentration. This model has mainly been built up from physical evidence. For condensed phases, however, conformity of physical properties to corresponding states has not been so extensively investigated. Previous rules relating to the entropy of vaporisation have been concerned mainly with the entropy difference between a liquid and vapour. This lack of interest has been largely due to the difficulty of synthesis. In most cases iodometric thiol determinations showed that acylation had occurred almost exclusively on thehydroxyl rather than on a thiol group. The titanium atom is normally considered to have a covalency maximum of six. The presence of these compounds has not been established unequivocally. At these temperatures the reaction is complex, and it is difficult to set up a mechanism which satisfies unambiguously all the observed facts. Ocotine can be assigned tentatively the molecular formula 3582. It is tentatively suggested that, in the solid, the anions are polymeric. They suggest the formation of B-H bonds in the pyrolysis product, which might therefore be tentatively formulated as follows. The structure of the long-known series of compounds has never been satisfactorily explained.

:

Although acid-hydrolysis of the product KH2N, B2H6 was fairly rapid, alkaline hydrolysis was slow and incomplete. The solid salt slowly evolved hydrogen at 150, but no diborane or borazole. Tri-methylamine reacted very slowly and incompletely. These facts do not support a formula KH3BNH2-BH3 for the salt, from which diborane or borazole would be expected as pyrolysis products, from


which trimethylamine might readily remove a borane group as Me3N' BH3, and which would be hydrolysed readily in acid or alkaline solution. The rapid acid and slow alkaline hydrolysis observed are however characteristic of an alkali-metal borohydride; this would not react readily with trimethylamine and would not decompose easily when heated. If the apparent KH2N, B2H6 does contain the borohydride KBH4, then the other constituent is probably polymerised aminoborine, H2N,BH2, and this also would not react with trimethylamine and would slowly yield hydrogen on being heated. The difficulty of completely replacing the methyl groups could then be explained if these were present in the polymeric aminoborine; their presence in the borohydride anion is much less probable. Potassium borohydride is soluble in liquid ammonia without reaction; aminoborine is slowly ammonolysed. The solid KH2N,B2He in liquid ammonia only evolved hydrogen very slowly even above 33, but addition of ammonium chloride produced rapid evolution at low temperature.

85. , , : mechanically, electrically, electrolytically, botani-cally, conductometrically, colorimetrically, potentiometrically, thermally, thermodynamically, azeotropically, gravimetrically, ste-reochemically, fractionally, structurally, quantitatively, qualitatively.

, , , . :

The technique consisted of making up mole-fractions by weight, sealing in Pyrex tubes, and rotating mechanically in a thermostat. The temperature was controlled electrically to + 0,05.

Today over 90 per cent of all tin plate is produced electrolytically. The authors wish to acknowledge the kindness of Mr. B. J. Rendle for examining the timbers botanically. The stepwise replacement of aquo-by amine-groups can be followed by titrating sulphitotriaquo-palladium (II) with ammonia, both conductometrically and potentiometrically. The compound dissolves exothermally in water to give a brown solution and a small precipitate of hydrated osmium dioxide. The criterion adopted is related thermodynamically to the Barclay-Butler equation between heats and entropies of vaporisation. Benzene was added and the water was removed azeotropically. Iodine was determined gravimetrically as silver iodide. It was considered that this would stereochemically be unfavourable for proton-loss, and would therefore allow this process to occur predominantly in the methyl groups. The acid-insoluble SPNC was fractionally crystallised to give 712 g. of tetramer (m. 122), 515 g. of a mixed


polymer fraction (69% of trimer, 20% of tetramer), 808 g. of a mixture of oil and crystals, and a light yellow oil.

86. , - , : fortunately, regrettably, unfortunately, undoubtedly, surprisingly (enough), obviously; originally, subsequently, eventually, finally; mathematically, physically, politically, scientifically, industrially; qualitatively, quantitatively.

. .

:

Fortunately the methanol solvate of the ester (VII) could be converted into the solvent-free compound without loss of crystal- limly. Regrettably there have been no new world shaft-sinking records established during Congress, though indications are that at least one attempt will be made later this year. Unfortunately, the structure of Meinhard's compound is open to doubt. Undoubtedly, the syrupy triketal fraction was a mixture of various isomeric forms. Surprisingly, perhaps, chromatographically homogeneous 1,3-0-benzylideneglycerol showed absorption at 3633 and 3593 cm"1. Obviously, the product formed from benzylsodium on prolonged storage is a poor initiator. Finally, positive proof of the presence of a methyl group on N(a) excludes structures in which N(a) is common to two rings, as in mavacurine and hunterine. Subsequently a number of the reactions with metal salts were investigated. Finally, heating at 200 produced more hydrogen than required by the reaction. Eventually, the system will contain only N- and 0-acetylethanolamine, the latter in an amount equivalent to that of acid originally added. Mathematically, there is no difference between this treatment and that described later in Section V. Physically, this may be regarded as an attraction of the surface for the ions immediately below it. Qualitatively, this is not unexpected.

. , -, , . :

Reaction between twTo benzyl radicals could lead eventually to phenanthrene or anthracene.

87. , - (. 221), : admittedly, announcedly, apparently, conceivably, reportedly, reputedly, seemingly, supposedly.

-, , it is admitted,


it is announced, it is apparent, it is conceived, it is reported, it is reputed, it seems, it is supposed (. 211). , , .

:

, . These interpretations are admittedly conjectural.

, . This is, announ-cedly, a very powerful reagent.

-, . The groups in the trans position apparently prevent this reaction.

, VI. Dibromohydrin VI conceivably could be produced as an intermediate.

, , . Silica hydrogel reportedly was prepared by combination of dilute sodium silicate and sulfuric acid in wooden tanks.

-, . The compound is seemingly difficultly soluble in concentrated ammonium hydroxide solution.

, -, . This discrepancy seemingly indicates different mechanisms of benzene formation.

, , , ( ), . The triphenylcarbinol ether shown in the equation undergoes tetrasulfonation, supposedly in the positions indicated.

, . A partial racemization could supposedly take place.

, . In a simple case, a separation could conceivably be carried out with very simple equipment.

88. : however, nevertheless, again, also, now, thus, on the other hand, alternatively, further, furthermore, conversely, therefore, in fact (. 8994).

, .


, - , -.

:

--2---. This is not so, however, in the case of the 3-phenyl-2-pentyl tosylates.

-. Unequivocal direct confirmation for the presence of an amino-group was nevertheless difficult to obtain.

:

Quantum-mechanical tunnelling in proton-transfer should be more easily detected the lower the temperature, and it is therefore of interest to measure the rates of such reactions at temperatures as low as possible.

We have also shown that with Grignard reagents aromatic thiol-acids give triarylmethanethiols.

We have now examined in some detail the reaction of titanium (IV) chloride with three primary aliphatic amines.

We have in fact found that solvolysis is greater with primary than with secondary amines. Both types of structure, however, contain phosphorus in three different environments, and should therefore exhibit three nuclear magnetic resonances. Only the intramolecular second moment was therefore calculated from the published data. At temperature above the optimum, on the other hand, the reaction takes place more rapidly but the catalyst is more rapidly destroyed. A given carbohydrase, on the other hand, has always the same optimum pH, even when acting upon different substrates.

.

:

It may be that an internal radical or ion rearrangement is occurring. Alternatively the radical might be formed by attack by D or D+ when the incoming particle might be confined to certain geometrical paths by virtue of the crystal structure. On the other hand there are a number of elements, whose salts form stronger adducts with sulphides than they do with oxygen-ethers. On the other hand, the polymerization initiated by the transformed benzylsodium produced a polymer. Further, the intensity of the characteristic peak at 505 m. was a maximum immediately the ketone had been mixed with alkali; in contrast, the intensity of the absorption band in a mixture of acetophenone, m-dinitrobenzene, and alcoholic potassium hydroxide increased steadily with time. Furthermore, spectroscopic examination of the coloured solutions produced in the test shows that the maximum absorption in the visible region is shifted to longer wavelength.


,

89. However. . . however1.

1. The Schmidt reaction has been run with as much as six moles of hydrazoic acid at one time, however.

2. However, the Schmidt reaction has been run with as much as six moles of hydrazoic acid at one time.

3. The Schmidt reaction has been run, however, with as much as six moles of hydrazoic acid at one time.

4. The Schmidt reaction, however, has been run with as much asjsix moles of hydrazoic acid at one time.

i. , however , , at one time. , , , 1, : In addition to these permissive arguments, however, there is more direct evidence that the hydrogen atom is taking part in the rate-controlling step of the reaction. It has, however, been pointed out that the only available experimental measurements do not support this suggestion. Theoretical studies of this model have, however, not been taken far enough to establish whether it provides an explanation of the behaviour of the quasi-spherical polyatomic molecules described in the present paper. They are generally in good agreement, however, with the results from the densimetric and X-ray methods within the limits of experimental error.

All these features suggest aromatic character. The ring differs, however, from that in benzene in that the formation of -bonds requires the use of a d-orbital at the phosphorus atom.

Style Book, . (, 1957), , however , , , .

-: however . , however ,; ,

1 L. and . i e s e r. Op. cit., p. 23. 8 . .


however . :

Neither preparation had a significant effect on the production of maltose from amylopectin-p-amylase or Floridean starch-p-amylase systems; by this criterion gross contamination with-a-amy-lase could be ruled out. However, when amylose, amylose (3-dextrin, or amylopectin p-dextrin was used as substrate, and assay was by iodine-staining and reducing power or viscosity, the presence of a trace of oc-amylase was established.

Although the tendency of trans-l,3-0-benzylideneglycerol to isomerise in the presence of acid has not been studied the cis-isomer is known to be sensitive to acid and to be rapidly and predominantly converted into 1,2-0-benzylideneglycerol. However, treatment of cis- and trans-l-3-O-benzylideneglycerol with pyridine-benzene-hydrogen chloride at 30 for 24 hr. had little effect.

From Table 2 it is obvious that the behaviour of the remaining three tervalent vanadium complexes we have studied is very similar to that of the alum. However, in view of the Weiss constant of 14, not too much significance can be placed on the result for the malonate.

All of the points obtained fell on a plateau, and the form of the isotherm at lower pressures can only be supposed to be similar to that for untreated firebrick. However, it is clear from the diagrams that saturation of the treated firebrick is reached at about one tenth of the equilibrium pressure for saturated untreated firebrick.

In principle the estimation of relative nucleophilicities in this system should not be difficult because the reactions are effectively irreversible, and so product yields should be directly proportional to the individual rates of reaction. However, other factors complicate such an analysis. The comparison of hydroxide and etho-xide ions, for example, is impracticable because of the base-catalysed exchange of OH by OEt with the hydroxy-compound (I) in ethanol. However, it can be shown that ethoxide ion is a stronger nucleophile towards the N-cyanoquinolinium ion than is the t-bu-tyl hydroperoxide ion, for only the ethoxy-compound (II) can be recovered from an equimolar solution with sodium t-butyl peroxide and sodium ethoxide in ethanol.

, , , , however .

:

, . , , 99%. When operating below the optimum temperature, unconverted antheracene and some highly


colored impurities were present. However, when operating at temperatures above the optimum, anthraquinone of greater than 99 per cent purity was readily obtained.

. However , . : ...however weak the bond..., ...however the reactionis carried out...; ... however a formula was written...

, however .

These fractions, however, trivial in themselves, interfere with isolation of the main product.

However, the reaction may proceed with inversion.

90. Again. , , , , (. 88). :

. , . The new procedure enabled us to overcome the above difficulties. Again there took place an unexpected drop in the demand for this product.

, , , , , . Thus finely powdered metals form very active catalysts, whilst again the heating of metallic surface until sintering occurs invariably leads to a loss of catalytic activity.

. Again this is in accord with experiment.

Q , , , U. Access is given to passage Q by two horizontal channels K, each of which is again connected to two passages U.

. The motion of a valency electron in its orbital is again equivalent to the flow of a current in the locus of its motion.

91. Also. , also (. 88).

8* 115


, , , . All these observations were made in solution, but a number of compounds were also examined in the solid state.

. , . Propionic acid is used for the manufacture of esters. is also used for calcium propionate.

:

It has also been shown that />-nitrotoluene and 2.4-dinitrotolue-ne exchange with deuterium oxide in the presence of bases.

Probably the most convincing reaction is the addition of hydrogen atoms to carbon monoxide, which has been shown by infrared and ultraviolet spectrophotometry to give rise to formyl radicals. Also the experiments with deuterated methanol and formic acid are significant in that they show the strongly coupled proton is attached to carbon in the parent compounds.

Thus it appears that polyanion formation is relatively easy with a transition-metal ion. Also if the radius ratio is small protonation of the oxygen seems to occur, weakening the metal-oxygen bond sufficiently for expansion to the octahedral state to occur.

92. N w. , , , , (. 88).

:

, , , . If the chain is now imagined to be rotated with the preservation of the valency angles, the side groups will become closer together.

, . The equations will now be derived on a statistical basis.

, , ( ), . The question now is what energy, if any, is required to bring about such a rotation.

, 46%. It has now been found possible to prepare the aldehyde in 46% yield.

93. Thus. thus . , , ,


, , , . thus (. 88).

:

, . , , - . The formation of the indole is often accompanied by the production of much tar, but in other cases it takes place remarkably easily. Thus the phenylhydrazone of cyclohexanone gives an almost quantitative yield of tetrahydrocarbazole when boiled for a few seconds with glacial acetic acid.

: , , , . Certain apparent anomalies can be easily explained. Thus, iso-propyl bromide gives less olefine than tret-butyl bromide when treated with dilute or strong solution of sodium ethoxide in alcohol.

. , , -, .

In the present study the addition of potassium reduced the rate constant. Thus it appears that the change is due to the chemical characteristics.

. In the early stages of decomposition, the volatile material is rich in hydrogen and thus takes up much oxygen.

, , . Although no means is available for calculating the effects of variation of structure on these forces, and thus on the melting, a number of empirical rules having some basis in theory have been developed.

1. -, thus , thus, for example; thus, for instance, . :

, , , . Thus, for example, ethyl-sodium will not react with benzene to form phenylsodium and ethane.


2. thus . :

These conditions are far more vigorous than those employed in the formation of the boron compound by hydroboration of 3,3,3-trifluoropropene. It is thus apparent that the 1,1-difluo-ropropene found after treatment of 3,3,3-trifluoropropene with diborane is not formed by decomposition. The stability of a ketal to the Huang-Minion conditions for the Wolff-Kishner reduction was thus demonstrated.

94. Alternatively. , , alternative : ; . , . :

, - 4 1,3--2-. .Alternatively ethylene'glycol and ethyl chloroformate in the presence of pyridine or sodium leads to 1,3-dioxalan-2 one.





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