NOTES
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Vol. 68
culation was undertaken. From the numerous highly branched isomers deviate slightly in proexainples in Table I, i t is possible to calculate ap- portion to the extent of branching. An alternative method of calculation which has proxiinate contributions of acetylenic carbon (C") and of the a , p, y, . . . ., w carbon atoiiis been employed eomrnotily with other types of combined thereto, assuiiiirig only that hydrogen compwnds is the use of alkyl group values deteris nornial, i. e . , contributes 1.100 per atom. 0 1 1 mined froin knowii compounds. The examples in this basis there is obviously no correction for the Table I make possible the assignment of group triple bond. The various calculations are best values for methyl, ethyl, %-propyl, n-butyl, t explained by the folltiwing examples. The ob- butyl, and a few others in the usual manner. served relracticm for 1-l)eiityne less 1,100 gives Unfortunately, however, such group values taken 22.0113 as the value for the group CH:{--CH2-- from several examples frequently disagree. Thus C H 2 - - C d - - ; one-half the observed value for the contribution for t-butyl calculated froin t-l-octyne, 18.754, is the contribution of CHsbutylacetylene is 19.749; taken froin di-t-butylCH2--CH2--C=. Thus one C3 contributes acetylene it is 20.201, both values based on 2.398 :i.?(i4, the difference between 22.015 and i8.734. for the triple bond correction. I t seems better, Siinilar calculatiuiis inatle by coinparison of I - therefore, to calculate the expected molecular reliesyne with S-decyne and of 3,R-dirnethyl-l- fraction by summation of the average cotitribugive tions of the various types of atoms in the molecule. butyiie with '7,?,5,3-tetraliiethyl-3-hexyne C" values of 3.293 and 3.1G3) respectively. The DEPARTMENT OF CHEMISTRY tion is only I).130 and the average UNIVERSITY OF NOTREDAME RECEIVED LfARCFI 29, 1946 of tlie three values, 3.220, is now taken as the XOTREDAME,INDIANA 11ie3iicoiitribution of one acetylenic carbon atom,
.
C" .
The Preparation of Some Tertiary Alcohols by 'Ik! value for dplza carbon atoms, Ca, was the Addition of Organic Acids to Grignard calculated from the data for 2-butyne: M R Reagents (
