April 26, 1873.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
843 
The wood is light, hut durable, and is used for shoes 
and other articles. It takes a good polish. 
2. S. lucida , Wall.; Plant. As. Rar. ii. t. 168; 
Planch, in Hook. Jl. Bot. v. 562. Very closely allied 
to S. indica, and perhaps only a variety. Leaves a 
lighter green, sometimes larger, and with longer 
petioles. Umbels almost sessile, or with the common 
peduncle much shorter than the leaves. Fruit 
smaller than in S. indica, pear-shaped, dark brown, 
glabrous, beautifully reticulated, with a very narrow 
wing. 
Eastern Peninsula and Andaman Islands. Nothing 
is known about its properties; it has probably been 
confounded with the former. 
(To be continued.) 
STJLPHOVINIC ACID AND THE STJLPHO- 
VINATES.* 
BY M. BERTHELOT. 
I. Reaction of Sulphuric Acid upon Alcohol. 
The reaction of sulphuric acid upon alcohol gives 
rise to very varying products, according to the tem¬ 
perature at which it occurs. 
(1.) If the two bodies, previously cooled, be gra¬ 
dually mixed, avoiding any rise of temperature, and 
keeping the whole at about 0°C., no reaction is at 
first produced ; but under the influence of a pro¬ 
longed contact, a peculiar sulphovinic acid is gra¬ 
dually formed, the salts of which differ from those 
of the ordinary acid, into which they are trans¬ 
formed under the influence of boiling. This acid, 
first noticed by Svanberg, and met with since by 
Gerhardt and myself, has been recently contested 
by Erlenmeyer, but, I think, wrongly. That author, 
not having operated with sufficient precautions, ob¬ 
tained, in fact, the ordinary acid in two different 
ways, so that he compared the salts of one and the 
same body. The existence of these special sulplio- 
vinates, which are more unstable than the ordinary 
sulphovinates, may be one of the causes of the spon¬ 
taneous alteration in the commercial salts. I shall, 
therefore, point out further on how their production 
they may be avoided. 
(2.) Mixture of concentrated acid and absolute 
alcohol, in equivalent proportions, without special 
precautions, gives rise to great disengagement of heat 
and the production of ordinary sulphovinic acid. 
The quantity of this acid immediately formed varies 
according to the mode of mixture; that is to say, 
according to the degree of local heat and the relative 
proportions in contact, and whether the acid or the 
alcohol is poured into the other. 
For example, upon mixing without precaution one 
part by weight of concentrated acid with five parts 
of alcohol, I have found that at the end of one hour 
10 per cent, of the acid was changed into sulpho¬ 
vinic acid, and at the end of twenty-four hours, 26 
per cent. On the contrary, upon mixing carefully one 
part by weight of concentrated acid and two parts of 
alcohol, scarcely any was etherified at the end of one 
hour, and a very' small percentage in twenty-four 
hours, although the excess of acid compared with the 
preceding experiment might be expected to favour 
* Abstract from a letter to M. Bussy, President of the 
Paris Society of Pharmacy (Journ. de Pharm. et de Cliimie 
£4], yoL xvii. p. 257). 
the combination. Be that as it may with these pre¬ 
liminary phenomena, under the influence of time the 
combination proceeds to a fixed limit, which it does 
not appear to pass. Thus, at the ordinary temperature, 
concentrated acid and absolute alcohol yield for 100 
parts of sulphuric-acid the following proportions of 
sulphovinic acid:— 
At the end of 40 hours. 56‘0 
» >> 90 „ . 59*0 
„ „ 147 days . 58'8 
The reaction is greatly accelerated by a suitable 
heat. In fact, if the temperature of such a mixture 
be kept at 100° C., 56 per cent, of sulphovinic acid 
may be obtained in four hours. It is necessary, 
however, to avoid the prolonged use of such a tem¬ 
perature, since, at the end of ten hours, there would 
remain but about 42 per cent. This retrograde 
action is due to a slow formation of ordinary ether, 
produced at the expense of the sulphovinic acid, and 
which tends to regenerate the sulphuric acid. 
(3.) The production of ordinary ether becomes 
very plentiful if the temperature be raised to about 
145° C.; at about 160° or 170° C., in consequence of 
a more complex reaction, even ethylene is formed. 
Although within these limits of temperature sulpho¬ 
vinic acid always exists in the mixture, in conse¬ 
quence of certain equilibriums between that acid, 
ether, ethylene, free sulphuric acid, alcohol, and 
water, it is advisable carefully to avoid such com¬ 
plications in the preparation of sulphovinic acid. 
It is therefore necessary to raise the temperature, 
to about 100° C., and maintain it for a short time, 
in order to provoke the formation of sulphovinic 
acid under its most stable form; but the temperature 
should not be raised too high, nor should the mixture 
be kept too long at 100° C. 
ii. Reaction of Water upon Sulphovinic Acid and its 
Salts. 
The influence of water upon the production of 
sulphovinic acid and its salts is illustrated by the fact 
that when equivalents of strong sulphuric acid and 
alcohol are mixed together, the production of the acid 
does not pass a certain limit, 59 per cent. This limit 
is due, as in the formation of other compound ethers, 
to the presence of water, a necessary product of 
etherification. In an inverse sense water will de¬ 
compose pure sulphovinic acid, and the decomposition 
will stop precisely at the same limit as the reciprocal 
combination. Between these four bodies, alcohol, 
sulphuric acid, sulphovinic acid and water, there is 
thus produced a certain equilibrium precisely as in 
the formation of other compound ethers. 
But the limit is not always exactly the same for 
the same equivalent relations, probably because the 
bibasic organic acids, which might be compared to the 
sulphuric acid,—such as oxalic, succinic and tartaric 
acids,—form at the same time two compounds, a 
neutral ether and an acid ether, a fact which I have 
verified. Consequently, in these cases, the acid 
standard is diminished 66 per cent, of its original 
value when equivalent quantities are used. Whereas 
I have ascertained that concentrated sulphuric acid 
only forms one compound with alcohol, an ethereal 
acid, to the exclusion of neutral sulphuric ether, which 
is not produced under these conditions ; also that the 
standard of the acid is only lowered 29'5 per cent. 
But if the limit be not the same, the general phe¬ 
nomena remain alike. Between the lour bodies, 
acid, alcohol, acid ether, and water, there is produced 
