Potassium hydroxide wood ashes

Potassium Carbonate. Except for small amounts produced by obsolete processes, eg, the leaching of wood ashes and the Engel-Precht process, potassium carbonate is produced by the carbonation, ie, via reaction with carbon dioxide, of potassium hydroxide. Potassium carbonate is available commercially as a concentrated solution containing ca 47 wt % K CO or in granular crystalline form containing 99.5 wt % K CO. Impurities are small amounts of sodium and chloride plus trace amounts (<2 ppm) of heavy metals such as lead. Heavy metals are a concern because potassium carbonate is used in the production of chocolate intended for human consumption. 

Acylglycerols can be hydrolyzed by heating with acid or base or by treatment with lipases. Hydrolysis with alkali is called saponification and yields salts of free fatty acids and glycerol. This is how soap (a metal salt of an acid derived from fat) was made by our ancestors. One method used potassium hydroxide potash) leached from wood ashes to hydrolyze animal fat (mostly triacylglycerols). (The tendency of such soaps to be precipitated by Mg and Ca ions in hard water makes them less useful than modern detergents.) When the fatty acids esterified at the first and third carbons of glycerol are different, the sec-... 

Sodium hydroxide (NaOFI), also called lye, soda lye, or caustic soda to distinguish it from potassium hydroxide (potash lye), is another important base. Flistorically, lye was obtained from the ashes of wood and used to make soap. Lye, however, is an extremely caustic chemical. It can cause serious chemical burns if it comes into contact with the skin and permanent blindness if it gets into the eyes. People had to be very careful while making the soap. They also had to make sure they got the mixture of lye and animal fat (lard) correct to keep from hurting themselves and their families. Because of its caustic (corrosive) nature, sodium hydroxide is also used as the active ingredient in oven and drain cleaners. 

Manufacture Potassium carbonate (potash) was formerly produced by the ashing of wood and other plant raw materials. Since the middle of the nineteenth century, the saline residues from the rock salt industry and salt deposits have been the raw materials for potassium carbonate production. The currently industrially most important process is the carbonation of electrolytically produced potassium hydroxide. 50% potassium hydroxide solution (e.g. from the mercury process) is saturated with carbon dioxide, the solution partially evaporated and the potassium carbonate hydrate K2CO3 1.5H2O which precipitates out is separated. After drying, the product is either marketed as potash hydrate or is calcined in a rotary tube furnace at temperatures of 250 to 350°C to anhydrous potassium carbonate. Anhydrous potassium carbonate is also produced in a fluidized bed process in which potassium hydroxide is... 

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. 

For thousands of years, soap was prepared by heating animal fat with wood ashes. Wood ashes contain potassium carbonate, which makes the solution basic. The modern commercial method of making soap involves boiling fats or oils in aqueous sodium hydroxide and adding sodium chloride to precipitate the soap, which is then dried and pressed into bars. Perfume can be added for scented soaps, dyes can be added for colored soaps, sand can be added for scouring soaps, and air can be blown into the soap to make it float in water. 

In statistical tables of mineral production, potash and K2O equivalents are listed. The term potash refers to a variety of water-soluble, potassium-containing salts. Historically, the term was used for the water-soluble component of wood ash which consists of K2CO3 and KOH. However, much ambiguity surrounds the word. Potash is used to refer to potassium carbonate and to potassium-containing fertilizers, while caustic potash typically refers to potassium hydroxide. Within agricultural terminology, muriate of potash is a mixture of KCl (>95%) and NaCl. The potash... 

This two-step process, shown in reaction form for 19 21 -l- 2-propanol, is known as saponification. Saponification means to make soap and the term comes from the ancient practice of using wood ashes (rich in potassium hydroxide) to convert animal fat to soap. Animal fat as well as vegetable oils is usually a mixture of triglycerides (23, the triester derivative of fatty acids, and glycerol, 24). Under these conditions, basic hydrolysis of all three ester units leads to formation of glycerol and the salt of the fatty acids. The salts of these fatty acids are solids and they are the fundamental constituent of what is known as soap. ... 

A soap made by the reaction of this fat with sodium hydroxide consists of sodium palmitate, CisHgiCOONa. The sodium soaps are solid at room temperature, and the potassium soaps are liquid. Potassium soaps (soft soap) used to be made by heating wood ashes, fat, and water (wood ashes contain potassium hydroxide or potassium carbonate). 

The choice of alkali was more difficult. In Leblanc s time, the alkali was generally a carbonate (C03) or hydroxide (OH) of potassium or sodium extracted from the ashes of salt-rich plants. For example, northerners made an odoriferous soft soap by burning wood and boiling its ashes with animal fat or fish oil. In Spain, Marseilles, Genoa, and Venice, hard Castile soap was made by boiling olive oil with the ashes of seaweed and shore plants. 

Soap has been used for cleaning for thousands of years. Xo one knows who invented it — but the method for making it was passed down from father to son, from mother to daughter. The early soap makers first had to burn wood to get potash (K2COs—see page, 59) or dried seaweed to get soda ash (Na,CO ).This was treated with lime to make potassium or sodium hydroxide (KOH or XaOH — see page 45), and this, in turn, was boiled with fat to make soap. Very much the same method is used today — except that the j... 

Typical fillers calcium carbonate, talc, glass fiber, glass beads, glass flakes, silica flour, wollastonite, mica, sepiolite, magnesium hydroxide, carbon black, clay, metal powders (aluminum, iron, nickel), steel fiber, si-licium carbide, phenolic microspheres, wood fiber and flour, antimony trioxide, hydrotalcite, zinc borate, bismuth carbonate, red phosphorus, potassium-magnesium aluminosilicate, fly ash, hydromagnesite-huntite... 

Let us mention the old tradition known from ethnology for the preparation of soaps by boiling animal fat with the ash that remains after the burning of beech wood. This ash contains potassium carbonate and hydroxide which serve as bases for the saponification. Interestingly, in the Arabic language, the word for ash is kali. The terms alkali or kalium (for the element potassium) were derived from this root. The arabic culture and tradition strongly influenced European alchemy and its transformation into modem chemistry. 

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