Alkali potassium

The iodine atom in iodobenzene (unlike that in the corresponding aliphatic compounds) is very resistant to the action of alkalis, potassium cyanide, silver nitrite, etc. This firm attachment of the iodine atom to the benzene ring is typical of aromatic halides generally, although in suitably substituted nitio-compounds, such as chloro-2,4-dinitrobenzene, the halogen atom does possess an increased reactivity (p. 262). 

For the reduction of nitro-compounds containing a group which may be attacked by nascent hydrogen, as, for example, an aldehyde group, an unsaturated side chain, and so on, special methods must he applied. In such cases ferrous hydroxide or iron powder (cf. Chap. VII. 5, arsanilic acid) are often used. The reduction is carried out thus a weighed amount of ferrous sulphate is caused to act, in the presence of alkali (potassium or sodium hydroxide, baryta), on the substance to he reduced. In this way it is possible to reduce, for example, o-nitro-benzaldehyde to aminobenzaldehyde, and o-nitrocinnamic acid to amino-cinnamic acid. 

This remarkable reaction occurs because alkalis (potassium hydroxide) convert benzoin partly into the di-enol form, i.e. into the potassium derivative of stilbenediol C6H5.COK COK.CgHg.1... 

C insoluble in water (about 5mg/L at 20°C) soluble in alkalies, potassium cyanide and ammonia solutions insoluble in alcohol. 

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). 

Near the end of the eighteenth century the difference between the two fixed alkalies—potassium and sodium carbonates—was known sodium carbonate barilla was largely made from the ashes of sea plants, and potash from the ashes of land plants. The Arabs also had brought some natural soda into Europe, via Spain. These sources were not sufficient to cope with the demand for alkali for the manufacture of soap, glass, etc. Potash was at that time the cheaper and dominant alkali. With the steadily increasing demands for alkali and the very limited sources of supply presented by the incineration of wood, many attempts were naturally made to substitute the base of common salt, because that with a suitable method of extraction nature has provided inexhaustible, abundant, and cheap... 

It is interesting to note that this process led, in the hands of Sir Humphry Davy, to the discovery of the metals of the alkalies, potassium and sodium he first prepared them by passing a current from a battery of high voltage... 

The nitrogenized substances obtained in this manner are washed, dried, and mixed with substances yielding oxygen. The nitrates of alkalies, potassium chlorate, and the strongest nitric acid (1.5 specific gravity) are principally used for the purpose. 

In a study of medieval glass, Olin and Sayre (10) noted that different levels of alkalis and even a different specific alkali—potassium rather than sodium, from beechwood ash—distinguish medieval glasses from glasses of... 

The core flow conductivity is primarily determined by the temperature, pressure, and alkali (potassium) seed level output by the combustor, with generator inlet temperature being the single most Important parameter governing the level of alkali seed ionization and, therefore, free electron production. 

A method, which is considered sufficiently accurate for technical purposes, for the estimation of alkali chromates and dichromates in presence of each other, depends upon titration mth acid or alkali. Potassium dichromate is titrated with potassium hydroxide in presence of phenolphthalein ... 

Sulphonic Acids to Hydroxyl Compounds.—(4) Reactions with alkalies by fusion. In the aliphatic series the most important synthetic reaction for the formation of hydroxyl derivatives is the treatment of the alkyl halides with silver hydroxide, which reaction we have said does not occur in the benzene series when the substitution is in the ring and not in the side chain. The most important method for preparing ring-hydroxyl compounds is by the fusion of a sulphonic acid or its salt with alkalies, potassium or sodium hydroxide, a reaction which does not occur with the aliphatic sulphonic acids. 

Mojiahedi, et al., reported experimental results of peat gasification in a pressurized fluidized-bed gasifier. A combined alkali (potassium and sodium) recoveiy of 105% was obtained. Alkali was distributed between Ae cyclone catch (97%), post cyclonc paniculate matter (6.7%) and vapor phase in flue gas (1.2%). Unlike Ae current work, alkalis were not accounted for in spent bed material but Ae results are oAerwise similar. 

The hot raw syngas at the gasifier outlet contains not only H2, CO, CH4, C02, sulfur, and nitrogen compounds, but also H20, alkali (potassium and sodium), and mercury. In order to prevent alkali corrosion of hot gas cleanup components and to avoid expensive materials and unreliable refractory-lined piping,200 201 it is necessary to reduce the temperature to less than 540 °C for complete condensation of the alkali vapor on particulates in the hot syngas. 

The reduction is effected by adding to the substance to be reduced, in tire presence of an alkali (potassium-, sodium-, or barium-hydroxide), a weighed quantity of ferrous sulphate. By this reaction, o-nitro-benzaldehyde is reduced to o-amidobenzaldehyde o-nitrocinnamic acid to o-amidocinnainic acid. 

Table 10.1 shows a comparison of some of the properties of several common alkalis. Potassium-based alkalis, the price of which is higher than sodium-based alkalis, are not included. They are considered when clay swelling and injectivity problems are expected. Some alkalis are further discussed and compared in the following sections. 

Fats and oils are triesters of the alcohol glycerol. When they are hydrolyzed by saponification, the products are soaps, which are the salts of long-chain carboxylic acids (fatty acid salts). According to Roman legend, soap was discovered by washerwomen following a heavy rain on Mons Sapo ("Mount Soap"). An important sacrificial altar was located on the mountain. The rain mixed with the remains of previous animal sacrifices—wood ash and animal fat—at the base of the altar. Thus the three substances required to make soap accidentally came together— water, fat, and alkali (potassium carbonate and potassium hydroxide, called potash, leached from the wood ash). The soap mixture flowed down the mountain and into the Tiber River, where the washerwomen quickly realized its value. 

EXPLOSION and FIRE CONCERNS flammable NFPA rating Health 2, Flammability 3, Reactivity 2 flashback along vapor trail may occur closed containers may rupture violently when heated incompatible with strong oxidizers and alkalies, potassium hydroxide, and copper combustion by-products may include hydrogen chloride and phosgene gas use dry chemical, foam, carbon dioxide, or flooding quantities of water for firefighting purposes. 

Potassium permanganate is obtained from manganese dioxide by oxidation in two stages. The first is carried out by fusion with alkali (potassium hydroxide) in the presence of air or another oxidizing agent and yields potassium manganate, K2Mn04. This is taken up in water and decomposed into potas-... 

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). 

Incompatibilities and Reactivities Strong oxidizers, strong alkalis, potassium hydroxide, copper [Note Usually contains inhibitors to prevent polymerization.]... 

The manufacture of soap (and glass) soon required a supply of alkali (potassium and sodium carbonates) that far outstripped supplies from natural sources. Forty-five companies merged at the end of the 1800s into the United Alkali Company, a colossal chemical concern based on the synthetic production of alkali. Much of the story of the synthetic alkali industry however begins in the 1700s with the story of the unfortunate chemist Nicolas Le Blanc. 

Fixed alkali Potassium carbonate, sodium c. Tartarus vitriolatus (Croll) (Potassium sulfate) ... 

In a long memoir on the methods of separating metals (1752) Scheffer remarks that (hot) concentrated sulphuric acid will dissolve silver from its alloy with gold, but says this acid was then more expensive than aqua fortis. If fixed alkali (potassium carbonate) solution is added to a solution of silver in aqua fortis and the bottle at once stoppered, there is no precipitate but if the stopper is removed there is a brisk effervescence and a precipitate is formed. Pure silver is obtained by fusing precipitated silver chloride with fixed alkali and a little nitre. ... 

In a memoir on spathic iron ore (ferrous carbonate) read in June 1774, Bayen showed that the mineral on heating or dissolving in acids lost what the English call fixed air . He used Hales s apparatus, measuring the elastic fluid or gas (gaz) evolved, which he found was absorbed by fixed alkali (potassium carbonate) to form a crystalline salt (potassium bicarbonate). He concluded that the mineral is a compound of i part of fixed air or gas and 3 parts of metallic iron, but it is really a compound of i part of fixed air and i -6 of ferrous oxide. 

DuhameP showed that trees could be grown in filtered and in distilled water, thus repeating Van Helmont s experiment. In a memoir on lime he showed that lime water is precipitated by a solution of mild alkali (potassium carbonate), which he attributed to the union of an acid in the lime with an earth in the alkali. He obtained crystals of potassium bicarbonate (cf. Cavendish, p. 317). He found that limestone lost nearly half its weight on burning to quicklime, but regained part on slaking by exposure to air, but a loss of 5 J oz. per lb. remained. This memoir was specially noticed by Lavoisier. ... 

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