Alkali vegetable

Pflanzen-. plant, vegetable, -abfklle, m.pl. plant (or vegetable) remains, -alkali, n, vegetable alkali (old name for potash, also for plant alkaloids), -alkaloid, n, plant alkaloid, vegetable alkaloid, -art, /. kind or speeies of plant. 

G.-F. Rouelle, A. S. Marggraf, and others showed experimentally that potash can be extracted from plants without the use of fire (11). In 1764 Marggraf, for example, prepared saltpeter by treating tartar with nitric acid. Since saltpeter was known to contain the vegetable alkali, the latter... 

P.-J. Maequer pointed out in his Dictionary of Chemistry (1778) that when plants are decomposed without combustion, acidic substances such as tartar and potassium acid oxalate are produced, that plants from which these acidic substances have been removed by extraction or distillation yield much less vegetable alkali than they otherwise would that by ignition tartar can be converted almost completely to this alkali (potassium carbonate) that the alkali in vegetable ash is therefore produced by the combustion of this acidic substance that decayed wood, in which the plant acids have been destroyed by fermentation, yields scarcely any alkali (as Boerhaave had observed) and that plants containing little or no acid yield on combustion little or no vegetable alkali (5). 

The necessity for the addition of a portion of alkali in order to form alum is also confirmed, said Lavoisier, by a very interesting observation of M. Monet [A.-G. Monnet (1734-1817)] on the earth extracted from the alum at Tolfa the chemical examination which he made of specimens of this earth, brought from Italy by M. Guettard, showed him that it contains a portion of fixed vegetable alkali already formed. It is doubtless to this alkali that this earth owes its property of furnishing... 

When M. H Klaproth analyzed some native alum (alunite) from Cape Miseno, near Naples, he computed that one thousand pounds of it contained 470 pounds of alum provided by Nature herself with the requisite quantity of pot-ash" and 290 pounds of alum whose crystallization is promoted by adding pot-ash (21). The presence of this alkali raised in his mind the question "As this grotto consists merely of volcanic tufa, in which no vegetation takes place, whence does Nature procure the vegetable alkali requisite to the generation of the crystalhzable alum (21). 

In an attempt to find out whether the presence of soda or potash depended on a specific difference in the plants which produce them or on the composition of the soils, du Hamel devoted many years to agricultural experiments, at his estate at Denainvilliers, on the culture of the common saltwort (Salsola kali), a plant used for the manufacture of soda ash. The final analyses of the ash of this plant proved that in the first year the mineral alkali still predominated, but that in succeeding years the vegetable alkali rapidly increased until finally, after a few generations, the soda had almost disappeared (50). In these experiments, he had for many years the invaluable and enthusiastic help of his brother, M. de Denainvilliers. In his eulogy of du Hamel in the History of the Academy of Sciences, the Marquis de Condorcet gave the following characterizations of the two brothers ... 

Klaproth s first analysis of lepidolite did not show the presence of any alkali. When he examined it a second time, however, he wrote Since the analysis of leucite, described in the earlier part of this work, has evidently proved that it contains the vegetable alkali as one of its essential constituent parts, it was to be expected that this alkaline substance might likewise be found in the mixture of various other species of stones and earths. The first confirmation of this conjecture has been afforded to me by the Lepidolite. His final analysis of "the amethystine red lepidolite yielded silica 54.50, alumina 38.25, potash 4, oxides of manganese and iron 0.75, and loss, partly consisting of water 2.50 per cent (71). Klaproth s analysis failed to show the presence of two essential constituents of lepidolite lithium (which had not yet been discovered) and fluorine. 

Potash Sulphate of Potash 2 Fixed vegetable alkali Vitriolated tartar Sel de duobus Arcanum duplicatum... 

Although their presently accepted stmctures were unknown, they were characterized with the tools available at the time. Because morphine (2, R = H), c17h19no3, was shown to have properties similar to the basic soluble salts obtained from the ashes of plants (alkali) it was categorized as a vegetable alkali or alkaloid, and it is generally accepted that it was for this case the word was coined. 

Vitriolic acid to calcareous earth 110 Nitrous acid to vegetable alkali 215... 

For many centuries, people had trouble telling vegetable alkali and mineral alkali apart. The two materials looked and acted very much alike. For example, they could both be used as cleaning materials. The main difference between them was the source from which they came. It was not until the 18th century that chemists understood the difference between potash (vegetable alkali) and soda ash (mineral alkali). 

Just as ammonia, NH3, is a weak base, there are a large number of nitro-gen-containii organic compounds called amines that are also weak bases. In the early days of organic chemistry, basic amines derived from natural sources were known as vegetable alkali, but they are now referred to as alkaloids. The study of alkaloids provided much of the impetus for the growth of organic chemistry in the nineteenth century, and it remains today a fascinating area of research. 

That a difference existed between soda and potash was only gradually realised. In 1702 Stahl distinguished between natural and artificial alkalis, evidently referring to soda and potash, noting that salts of the former sometimes possessed a different crystalline form from the corresponding salts of the latter. In 1736 Duhamel de Monceau observed further differences between mineral alkali, that is soda, and vegetable alkali or potash,... 

Dr Wall had taken the deposit to be fixed vegetable alkali (potassium carbonate) but Higgins showed it to be mainly nitre, an analysis confirmed by John Kidd, the Aldrichian Professor of Chemistry, in 1814 (see the next chapter for further details). 

Fownes determined the equivalent of carbon by the combustion of naphthalene (C5H2 i.e. CioHg)/ discovered a new organic base benzoline from oil of bitter almonds, which was really Laurent s hydrobenzamide, and obtained furfurol by the action of sulphuric acid on bran and prepared a vegetable alkali (furfuramide) by the action of ammonia on it. Fownes mentions that furfurol had been noticed and named by William Coley Jones. Jones says upon distilling the lignin of wheat in a manner which I shall describe (but does not) he obtained a liquid of s.g. i-iyS-i iSy, b.p. 208 F., many chemical reactions of which he describes in detail. He says I have named the body furfurol torn furfur bran and oleum oil, being a peculiar essential oil produced from that body, either as an educt or product. He found that it is inflammable. Furfurol (kiinstliches Ameisenol, artificial oil of ants) had been discovered by Dobereiner (seep. 179). 

Thus the affinity of the vitriolic add to fixed vegetable alkali, that is, the force with which they unite, or tend to unite, to each other, is to the affinity with which that same... 

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