20 . Nitrogen is purified by passage through a 20 cm length of metallic copper.
, . The resulting chloracetocatechol is treated with aqueous methylamine solution whereby methylaminoacetocatechol is formed.
33. - , before, at, in, after, following, on, regarding, due to, on the basis of, by means of.
:
. The grease layer must be removed with solvent before development of the plates.
0. At suitable dilution the solution, after mixing, can be cooled to 0.
. Only one of the two carbo-nyl groups is affected in reduction of diacetyl.
. The reactant gases usually enter the catalyst bed at uniform temperature.
1 . After incubation for 1 hr., the cells were gathered rapidly in a refrigerated centrifuge and frozen.
. Following regeneration the catalyst is ready for the next cycle.
, . The Staden acid is a product obtained on drastic oxidation of cholestanol.
, . Vocke later found two isomeric perhydrodiphenic acids to slowly lose carbon dioxide on pyrolysis and afford ketones.
, , , , . The waves travelling backward are oddly said to have negative energy or mass according to the definitions in quantum theory)).
. The Lederle group made a similar observation regarding ethylenketal formation.
. The copolymer compositions determined are subject to errors due to incorporation of catalyst of solvent fragments.
. On the basis of orientation.
- . Strominger has investigated the acid-soluble extract by means of anion exchange chroma-tog raphy.
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. The alcohols gave, on dehydration, propanes.
. This usage is not followed in carbohydrate chemistry.
, . An investigation, which thus far has been reported only in preliminary communication.
5* 67
, . The acids were obtained pure only after very wasteful crystallisation.
, . The yields on cyclisation are low and the products need careful purification.
. Allyl alcohol on bromination takes on two atoms of bromine.
34. in + , .
: in energy, in intensity, in degree, in accuracy, in course, in value, in yield, in number.
:
. They differ in energy from that of the incident beam.
. The band is occasionally weak in intensity.
, , . Evidently the samples varied somewhat in degree of purity, or else there was some variation in accuracy of determination of melting point.
, . The reaction of water vapour is identical in course but diminished in intensity.
. The rate constant falls in value with increasing methanol concentration.
, . Methods initially reported for conversion of hecogenin to cortisone left something to be desired in yield and number of steps, but nevertheless present points of interest.
35. : to lead to, to be due to, to result from, to attribute to, to turn to, to expose to, to respond to, to judge by, to be based on (upon), to be independent of.
:
, . This led to fission of the isoparaffin into fragments which added to the olefin.
. The phenomenon is due to transition of electrons from one orbital to another.
, . It was originally inferred that the step in nitric acid solutions resulted from reduction of pentavalent niobium.
600 , . Alumina has a water content of several per cent even at 600 , which can be attributed to chemisorption.
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- . Van Hoff turned to physical chemistry and eventually won the Nobel Prize for outstanding contributions in this field.
, . Phage infected bacteria were exposed to photoreactivating light rather than to continuous illumination.
. Vinyl alkyl ethers do not respond readily to polymerization by heating or by the use of peroxide catalysts.
, , , . The synthesis of certain adaptive enzymes is inhibited but energy metabolism, as judged by respiration, continues.
To, , . The placing of an angular methyl group at Cu in the old formula was based upon sound evidence.
. This potential is generally constant and independent of concentration.
, , , , . The slight discrepancies are greater than the errors involved in the measurements and so are probably due to unavoidable sorption.
, , . The process leading to nitrosation may
consist of several steps, and take a number of alternative courses, depending on the nitrosation carrier.
36. to undergo, to involve, to come to, to maintain, to present, to offer, to effect, to seek, to reach, to acquire, to require, to favour, to prevent . ., : isomerisation, polymerisation, racemisation, oxidation, ovulation, conception, . .; hydrolysis, hydrogenation . ., research, account, conclusion, control, verification, consideration . .; stability, pressure, moisture . . :
, . Experiments indicate that the butenyl intermediate is free to undergo isomerisation.
. This compound undergoes ready dramatization in the presence of alkali.
6 - , 5,6- . An alternate route to a 6 a-methyl steroid involves hydroformulation of a starting material having a 5,6-double bond and no other reactive groups.
5 6 . Both columns require five to six hours to come to equilibrium.
, 1951 . Rushton and Krieger have presented rather detailed account of the work which had been done in this field through 1950.
. These characteristic rearrangements offer excellent diagnostic help in elucidating the mechanistic path involving primary elimination.
, , . Many of the catalysts which are used for hydrogenation will, under other conditions, effect partial hydrogenation or dehydrogenatiom.
. Authors sought further evidence of the location of the double bonds.
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- 32. Friedel-Crafts alkylations rarely, if ever, acquire enough 3:2 character.
. Both groups of workers reached essentially similar conclusion about the structure of the phage tail.
, , , . Methods producing good yields of thiophensulfuric acids require either inert solvents or careful control of reaction temperatures.
, , , . Low temperatures, of course, favour stability, especially if other conditions are suboptimal.
. The basic solvent used prevents lactone formation.
, , . Since progesterone prevents ovulation during pregnancy, it seemed possible that an analog of suitable high potency might be capable of preventing ovulation and so prevent conception.
. Toluene does not readily undergo autoxidation.
6- , . The property of undergoing reversible polymerisation is common to many 6-ringe containing ester linkages.
, , , . Compounds which have reactive functional groups directly attached to the asymmetric carbon atom undergo racemization.
, . One of the stopcocks must be open at all times to prevent excess gas pressure from opening the acid reservoir.
, , , , . It would be unfortunate if an arbitrary definition prevented consideration, side by side, of reactions believed to have similar mechanisms.
. Care must be taken to prevent moisture from the bottle diffusing into the carbon dioxide tube.
37. , chapter, table, figure, equation, formula, type, case, fraction, appendix . . .
:
V, , . As Chapter V has indicated, gas reactions are invariably of the ho-molytic type, and involve electrically neutral particles, such as atoms and neutral radicals.
1 , N- 1,06: 1. The molecular ratio of galactose to N-acetylhexosamine can be computed from the data in Table 1 to be 1.06:1.
. 2 . In figure 2 is shown a representative diagram of levels of energy.
, , XVII. No structure is possible other than that indicated in formula XVII.
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, I, II III. For convenience we designate the three fundamentally different types of selectivity by Type I, Type II and Type lib).
(2). We may now proceed to case (2).
I , II , III IV . Fraction I contained mainly xylan and galactan, fraction II xylan together with appreciable amounts of glucomannan, and fractions III and IV mainly glucomannan with smaller amounts of xylan.
, 18, . The list of common amino acids given in Table IS includes isoelectric points.
VI, . This question will be taken up in Chapter VI where the whole subject of the measurement will be discussed.
38. , , :
1) , : Lomonosov, Men-delyeev, Semenov, Moscow, London, New York, Great Britain, Russia, France . .;
2) , , , . : Father, Mother, Aunt, Uncle, Nurse, Baby, Child;
3) , , : January, February, March, Spring, Summer, Autumn, Winter, Monday, Tuesday, Wednesday , .;
4) , : Southern France, Northern England, Central Africa, Ancient Rome.
39. , . , .
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to take into account (consideration) ,
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in addition ,
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in advance , ,
to advantage
to be of advantage ()
to take advantage of ,
to be in agreement with , ,
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to make appearance
at hand ,
at issue 1) ; 2)
at length 1) , , ; 2)
at request
at rest ()
at will ,
to claim attention () ( )
background of experience
background of information
to be in agreement , ,
to be in charge of ,
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to be of importance
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, to bear relationship (resemblance) ,
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in bulk 1) , , ; 2) ,
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by reason of , , - in comparison with (to) for comparison with (to) in connection with
in consequence , in consequence of , for consideration
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by way of , , , to call into action (being, play) , ,
,
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| I , |
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in view of what follows ,
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off hand ,
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in behalf of ,
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in part ,
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(-)
the point in question , point of interest point of (much) controversy () point of view
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,
of reference , , without reference to , without regard for
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beyond all shadow of doubt
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step by step
as part of the study
under study
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to meet with success
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to take place , ,
wear and tear
under test
ahead of time , 'f'from time to time ; just in time -
