Sodium hydroxide , also known as lye and caustic soda , is an inorganic compound with the formula NaOH . It is a white solid ionic compound consisting of sodium cations Na and hydroxide anions OH .
73-597: Soap is a surfactant cleaning compound used for personal or other cleaning. Soap may also refer to: Soap Soap is a salt of a fatty acid (sometimes other carboxylic acids) used for cleaning and lubricating products as well as other applications. In a domestic setting, soaps, specifically "toilet soaps", are surfactants usually used for washing , bathing , and other types of housekeeping . In industrial settings, soaps are used as thickeners , components of some lubricants , emulsifiers , and catalysts . Soaps are often produced by mixing fats and oils with
146-501: A base . Humans have used soap for millennia; evidence exists for the production of soap-like materials in ancient Babylon around 2800 BC. In a domestic setting, "soap" usually refers to what is technically called a toilet soap, used for household and personal cleaning. Toilet soaps are salts of fatty acids with the general formula ( RCO 2 )M , where M is Na (sodium) or K (potassium). When used for cleaning, soap solubilizes particles and grime, which can then be separated from
219-556: A primary standard because it is hygroscopic and absorbs carbon dioxide from air. Sodium hydroxide also reacts with acidic oxides , such as sulfur dioxide . Such reactions are often used to " scrub " harmful acidic gases (like SO 2 and H 2 S ) produced in the burning of coal and thus prevent their release into the atmosphere. For example, Glass reacts slowly with aqueous sodium hydroxide solutions at ambient temperatures to form soluble silicates . Because of this, glass joints and stopcocks exposed to sodium hydroxide have
292-485: A rheology modifier. Metal soaps can be prepared by neutralizing fatty acids with metal oxides: A cation from an organic base such as ammonium can be used instead of a metal; ammonium nonanoate is an ammonium-based soap that is used as an herbicide. Another class of non-toilet soaps are resin soaps , which are produced in the paper industry by the action of tree rosin with alkaline reagents used to separate cellulose from raw wood. A major component of such soaps
365-487: A soda ash substance called trona . Egyptian documents mention a similar substance was used in the preparation of wool for weaving. In the reign of Nabonidus (556–539 BC), a recipe for a soap-like substance consisted of uhulu [ashes], cypress [oil] and sesame [seed oil] "for washing the stones for the servant girls". True soaps, which we might recognise as soaps today, were different to proto-soaps. They foamed, were made deliberately, and could be produced in
438-524: A characteristic viscosity , 78 m Pa ·s, that is much greater than that of water (1.0 mPa·s) and near that of olive oil (85 mPa·s) at room temperature. The viscosity of aqueous NaOH , as with any liquid chemical, is inversely related to its temperature, i.e., its viscosity decreases as temperature increases, and vice versa. The viscosity of sodium hydroxide solutions plays a direct role in its application as well as its storage. Sodium hydroxide can form several hydrates NaOH· n H 2 O , which result in
511-458: A clear solution of Na 2 ZnO 2 or Na 2 PbO 2 . Aluminium hydroxide is used as a gelatinous flocculant to filter out particulate matter in water treatment . Aluminium hydroxide is prepared at the treatment plant from aluminium sulfate by reacting it with sodium hydroxide or bicarbonate. Sodium hydroxide can be used for the base-driven hydrolysis of esters (also called saponification ), amides and alkyl halides . However,
584-540: A complex solubility diagram that was described in detail by Spencer Umfreville Pickering in 1893. The known hydrates and the approximate ranges of temperature and concentration (mass percent of NaOH) of their saturated water solutions are: Early reports refer to hydrates with n = 0.5 or n = 2/3, but later careful investigations failed to confirm their existence. The only hydrates with stable melting points are NaOH·H 2 O (65.10 °C) and NaOH·3.5H 2 O (15.38 °C). The other hydrates, except
657-495: A hard or soft form because of an understanding of lye sources. It is uncertain as to who was the first to invent true soap. Knowledge of how to produce true soap emerged at some point between early mentions of proto-soaps and the first century AD. Alkali was used to clean textiles such as wool for thousands of years but soap only forms when there is enough fat, and experiments show that washing wool does not create visible quantities of soap. Experiments by Sally Pointer show that
730-431: A liquid solution. Even the n = 3.5 hydrate is difficult to crystallize, because the solution supercools so much that other hydrates become more stable. A hot water solution containing 73.1% (mass) of NaOH is a eutectic that solidifies at about 62.63 °C as an intimate mix of anhydrous and monohydrate crystals. A second stable eutectic composition is 45.4% (mass) of NaOH, that solidifies at about 4.9 °C into
803-407: A liquid with 35.7% NaOH and density 1.392 g/cm , and therefore floats on it like ice on water. However, at about 4.9 °C it may instead melt incongruously into a mixture of solid NaOH·3.5H 2 O and a liquid solution. The β form of the tetrahydrate is metastable, and often transforms spontaneously to the α form when cooled below −20 °C. Once initiated, the exothermic transformation
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#1732863222986876-642: A major cottage industry, with sources in Nablus , Fes , Damascus , and Aleppo . Soapmakers in Naples were members of a guild in the late sixth century (then under the control of the Eastern Roman Empire ), and in the eighth century, soap-making was well known in Italy and Spain. The Carolingian capitulary De Villis , dating to around 800, representing the royal will of Charlemagne , mentions soap as being one of
949-749: A man who worked for drug cartels admitted disposing of over 300 bodies with it. Sodium hydroxide is a dangerous chemical due to its ability to hydrolyze protein. If a dilute solution is spilled on the skin, burns may result if the area is not washed thoroughly and for several minutes with running water. Splashes in the eye can be more serious and can lead to blindness. Strong bases attack aluminium . Sodium hydroxide reacts with aluminium and water to release hydrogen gas. The aluminium takes an oxygen atom from sodium hydroxide, which in turn takes an oxygen atom from water, and releases two hydrogen atoms. The reaction thus produces hydrogen gas and sodium aluminate . In this reaction, sodium hydroxide acts as an agent to make
1022-477: A minimum quantity of one imperial ton at each boiling, which placed the process beyond the reach of the average person. The soap trade was boosted and deregulated when the tax was repealed in 1853. Industrially manufactured bar soaps became available in the late 18th century, as advertising campaigns in Europe and America promoted popular awareness of the relationship between cleanliness and health. In modern times,
1095-491: A mixture of crystals of the dihydrate and of the 3.5-hydrate. The third stable eutectic has 18.4% (mass) of NaOH. It solidifies at about −28.7 °C as a mixture of water ice and the heptahydrate NaOH·7H 2 O . When solutions with less than 18.4% NaOH are cooled, water ice crystallizes first, leaving the NaOH in solution. The α form of the tetrahydrate has density 1.33 g/cm . It melts congruously at 7.55 °C into
1168-571: A pleasant smell was produced in the Middle East during the Islamic Golden Age , when soap-making became an established industry. Recipes for soap-making are described by Muhammad ibn Zakariya al-Razi (c. 865–925), who also gave a recipe for producing glycerine from olive oil . In the Middle East, soap was produced from the interaction of fatty oils and fats with alkali . In Syria , soap
1241-452: A small soap works in Warrington in 1886 and founded what is still one of the largest soap businesses, formerly called Lever Brothers and now called Unilever . These soap businesses were among the first to employ large-scale advertising campaigns. Liquid soap was invented in the nineteenth century; in 1865, William Sheppard patented a liquid version of soap. In 1898, B.J. Johnson developed
1314-402: A soap derived from palm and olive oils; his company, the B.J. Johnson Soap Company , introduced " Palmolive " brand soap that same year. This new brand of soap became popular rapidly, and to such a degree that B.J. Johnson Soap Company changed its name to Palmolive . In the early 1900s, other companies began to develop their own liquid soaps. Such products as Pine-Sol and Tide appeared on
1387-495: A soap manufactory. The method of extraction proceeded on a discovery of Keir's. In 1790, Nicolas Leblanc discovered how to make alkali from common salt . Andrew Pears started making a high-quality, transparent soap, Pears soap , in 1807 in London. His son-in-law, Thomas J. Barratt , became the brand manager (the first of its kind) for Pears in 1865. In 1882, Barratt recruited English actress and socialite Lillie Langtry to become
1460-399: A soap-like substance was written on a Sumerian clay tablet around 2500 BC. This was produced by heating a mixture of oil and wood ash , the earliest recorded chemical reaction, and used for washing woolen clothing. The Ebers papyrus (Egypt, 1550 BC) indicates the ancient Egyptians used a soap-like product as a medicine and created this by combining animal fats or vegetable oils with
1533-487: A surfactant, when lathered with a little water, soap kills microorganisms by disorganizing their membrane lipid bilayer and denaturing their proteins . It also emulsifies oils, enabling them to be carried away by running water. When used in hard water , soap does not lather well but forms soap scum (related to metallic soaps , see below). So-called metallic soaps are key components of most lubricating greases and thickeners. A commercially important example
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#17328632229861606-491: A tendency to "freeze". Flasks and glass-lined chemical reactors are damaged by long exposure to hot sodium hydroxide, which also frosts the glass. Sodium hydroxide does not attack iron at room temperature, since iron does not have amphoteric properties (i.e., it only dissolves in acid, not base). Nevertheless, at high temperatures (e.g. above 500 °C), iron can react endothermically with sodium hydroxide to form iron(III) oxide , sodium metal, and hydrogen gas. This
1679-496: Is lithium stearate . Greases are usually emulsions of calcium soap or lithium soap and mineral oil . Many other metallic soaps are also useful, including those of aluminium , sodium , and mixtures thereof. Such soaps are also used as thickeners to increase the viscosity of oils. In ancient times, lubricating greases were made by the addition of lime to olive oil , which would produce calcium soaps. Metal soaps are also included in modern artists' oil paints formulations as
1752-415: Is a colorless crystalline solid that melts at 318 °C (604 °F) without decomposition and boils at 1,388 °C (2,530 °F). It is highly soluble in water, with a lower solubility in polar solvents such as ethanol and methanol . Sodium hydroxide is insoluble in ether and other non-polar solvents. Similar to the hydration of sulfuric acid, dissolution of solid sodium hydroxide in water
1825-464: Is a curved blade with a handle, all of which is made of metal. The 2nd-century AD physician Galen describes soap-making using lye and prescribes washing to carry away impurities from the body and clothes. The use of soap for personal cleanliness became increasingly common in this period. According to Galen, the best soaps were Germanic, and soaps from Gaul were second best. Zosimos of Panopolis , circa 300 AD, describes soap and soapmaking. In
1898-424: Is a highly exothermic reaction where a large amount of heat is liberated, posing a threat to safety through the possibility of splashing. The resulting solution is usually colorless and odorless. As with other alkaline solutions, it feels slippery with skin contact due to the process of saponification that occurs between NaOH and natural skin oils. Concentrated (50%) aqueous solutions of sodium hydroxide have
1971-429: Is complete in a few minutes, with a 6.5% increase in volume of the solid. The β form can be crystallized from supercooled solutions at −26 °C, and melts partially at −1.83 °C. The "sodium hydroxide" of commerce is often the monohydrate (density 1.829 g/cm ). Physical data in technical literature may refer to this form, rather than the anhydrous compound. NaOH and its monohydrate form orthorhombic crystals with
2044-416: Is cooled, the monohydrate normally starts to crystallize (at about 22 °C) before the dihydrate. However, the solution can easily be supercooled down to −15 °C, at which point it may quickly crystallize as the dihydrate. When heated, the solid dihydrate might melt directly into a solution at 13.35 °C; however, once the temperature exceeds 12.58 °C it often decomposes into solid monohydrate and
2117-562: Is due to the lower enthalpy of formation of iron(III) oxide (−824.2 kJ/mol) compared to sodium hydroxide (−500 kJ/mol) and positive entropy change of the reaction, which implies spontaneity at high temperatures ( ΔST > ΔH , ΔG < 0 ) and non-spontaneity at low temperatures ( ΔST < ΔH , ΔG > 0 ). Consider the following reaction between molten sodium hydroxide and finely divided iron filings: A few transition metals , however, may react quite vigorously with sodium hydroxide under milder conditions. In 1986, an aluminium road tanker in
2190-460: Is formed is toxic and difficult to deal with, and the process is banned in many countries because of this. In 2006, Trafigura used the process and then dumped the waste in Ivory Coast . Other common uses of sodium hydroxide include: Sodium hydroxide is also widely used in pulping of wood for making paper or regenerated fibers. Along with sodium sulfide , sodium hydroxide is a key component of
2263-495: Is given by: This reaction can be useful in etching , removing anodizing, or converting a polished surface to a satin-like finish, but without further passivation such as anodizing or alodining the surface may become degraded, either under normal use or in severe atmospheric conditions. In the Bayer process , sodium hydroxide is used in the refining of alumina containing ores ( bauxite ) to produce alumina ( aluminium oxide ) which
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2336-416: Is highly soluble in water , and readily absorbs moisture and carbon dioxide from the air . It forms a series of hydrates NaOH· n H 2 O . The monohydrate NaOH·H 2 O crystallizes from water solutions between 12.3 and 61.8 °C. The commercially available "sodium hydroxide" is often this monohydrate, and published data may refer to it instead of the anhydrous compound. As one of
2409-462: Is industrially produced, first as a 32% solution, and then evaporated to a 50% solution by variations of the electrolytic chloralkali process . Chlorine gas is also produced in this process. Solid sodium hydroxide is obtained from this solution by the evaporation of water. Solid sodium hydroxide is most commonly sold as flakes, prills , and cast blocks. In 2022, world production was estimated at 83 million dry tonnes of sodium hydroxide, and demand
2482-448: Is more skin-friendly than one without extra fat, although it can leave a "greasy" feel. Sometimes, an emollient is added, such as jojoba oil or shea butter . Sand or pumice may be added to produce a scouring soap. The scouring agents serve to remove dead cells from the skin surface being cleaned. This process is called exfoliation . To make antibacterial soap, compounds such as triclosan or triclocarban can be added. There
2555-493: Is reputed for its particular mildness. The term "Castile" is also sometimes applied to soaps from a mixture of oils with a high percentage of olive oil. Proto-soaps, which mixed fat and alkali and were used for cleansing, are mentioned in Sumerian , Babylonian and Egyptian texts. The earliest recorded evidence of the production of soap-like materials dates back to around 2800 BC in ancient Babylon. A formula for making
2628-402: Is some concern that use of antibacterial soaps and other products might encourage antimicrobial resistance in microorganisms. The type of alkali metal used determines the kind of soap product. Sodium soaps, prepared from sodium hydroxide , are firm, whereas potassium soaps, derived from potassium hydroxide , are softer or often liquid. Historically, potassium hydroxide was extracted from
2701-511: Is sometimes left in the soap product as a softening agent, although it is sometimes separated. Handmade soap can differ from industrially made soap in that an excess of fat or coconut oil beyond that needed to consume the alkali is used (in a cold-pour process, this excess fat is called "superfatting"), and the glycerol left in acts as a moisturizing agent. However, the glycerine also makes the soap softer. The addition of glycerol and processing of this soap produces glycerin soap . Superfatted soap
2774-465: Is the raw material used to produce aluminium via the electrolytic Hall-Héroult process . Since the alumina is amphoteric , it dissolves in the sodium hydroxide, leaving impurities less soluble at high pH such as iron oxides behind in the form of a highly alkaline red mud . Other amphoteric metals are zinc and lead which dissolve in concentrated sodium hydroxide solutions to give sodium zincate and sodium plumbate respectively. Sodium hydroxide
2847-411: Is the sodium salt of abietic acid . Resin soaps are used as emulsifiers. The production of toilet soaps usually entails saponification of triglycerides , which are vegetable or animal oils and fats. An alkaline solution (often lye or sodium hydroxide ) induces saponification whereby the triglyceride fats first hydrolyze into salts of fatty acids. Glycerol (glycerin) is liberated. The glycerin
2920-409: Is used in many scenarios where it is desirable to increase the alkalinity of a mixture, or to neutralize acids. For example, in the petroleum industry, sodium hydroxide is used as an additive in drilling mud to increase alkalinity in bentonite mud systems, to increase the mud viscosity , and to neutralize any acid gas (such as hydrogen sulfide and carbon dioxide ) which may be encountered in
2993-456: The Solvay process in the late 19th century. The conversion of sodium carbonate to sodium hydroxide was superseded entirely by the chloralkali process , which produces sodium hydroxide in a single process. Sodium hydroxide is also produced by combining pure sodium metal with water. The byproducts are hydrogen gas and heat, often resulting in a flame. This reaction is commonly used for demonstrating
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3066-467: The chloralkali process . Historically, sodium hydroxide was produced by treating sodium carbonate with calcium hydroxide (slaked lime) in a metathesis reaction which takes advantage of the fact that sodium hydroxide is soluble, while calcium carbonate is not. This process was called causticizing. The sodium carbonate for this reaction was produced by the Leblanc process in the early 19th century, or
3139-578: The geological formation as drilling progresses. Another use is in salt spray testing where pH needs to be regulated. Sodium hydroxide is used with hydrochloric acid to balance pH. The resultant salt, NaCl, is the corrosive agent used in the standard neutral pH salt spray test. Poor quality crude oil can be treated with sodium hydroxide to remove sulfurous impurities in a process known as caustic washing . Sodium hydroxide reacts with weak acids such as hydrogen sulfide and mercaptans to yield non-volatile sodium salts, which can be removed. The waste which
3212-604: The Mediterranean olive-growing regions. Hard toilet soap was introduced to Europe by Arabs and gradually spread as a luxury item. It was often perfumed. By the 15th century, the manufacture of soap in Christendom often took place on an industrial scale, with sources in Antwerp , Castile , Marseille , Naples and Venice . In France, by the second half of the 16th century, the semi-industrialized professional manufacture of soap
3285-530: The Southern Levant , the ashes from barilla plants , such as species of Salsola , saltwort ( Seidlitzia rosmarinus ) and Anabasis , were used to make potash . Traditionally, olive oil was used instead of animal lard throughout the Levant, which was boiled in a copper cauldron for several days. As the boiling progresses, alkali ashes and smaller quantities of quicklime are added and constantly stirred. In
3358-491: The Tudor period that barrels of ashes were imported for the manufacture of soap. Finer soaps were later produced in Europe from the 17th century, using vegetable oils (such as olive oil ) as opposed to animal fats. Many of these soaps are still produced, both industrially and by small-scale artisans. Castile soap is a popular example of the vegetable-only soaps derived from the oldest "white soap" of Italy. In 1634 Charles I granted
3431-590: The UK was mistakenly used to transport 25% sodium hydroxide solution, causing pressurization of the contents and damage to tankers. The pressurization is due to the hydrogen gas which is produced in the reaction between sodium hydroxide and aluminium: Unlike sodium hydroxide, which is soluble, the hydroxides of most transition metals are insoluble, and therefore sodium hydroxide can be used to precipitate transition metal hydroxides. The following colours are observed: Zinc and lead salts dissolve in excess sodium hydroxide to give
3504-407: The article being cleaned. The insoluble oil/fat "dirt" become associated inside micelles , tiny spheres formed from soap molecules with polar hydrophilic (water-attracting) groups on the outside and encasing a lipophilic (fat-attracting) pocket, which shields the oil/fat molecules from the water, making them soluble. Anything that is soluble will be washed away with the water. In hand washing , as
3577-633: The ashes of bracken or other plants. Lithium soaps also tend to be hard. These are used exclusively in greases . For making toilet soaps, triglycerides (oils and fats) are derived from coconut, olive, or palm oils, as well as tallow . Triglyceride is the chemical name for the triesters of fatty acids and glycerin . Tallow, i.e., rendered fat, is the most available triglyceride from animals. Each species offers quite different fatty acid content, resulting in soaps of distinct feel. The seed oils give softer but milder soaps. Soap made from pure olive oil , sometimes called Castile soap or Marseille soap ,
3650-406: The case of lard, it required constant stirring while kept lukewarm until it began to trace. Once it began to thicken, the brew was poured into a mold and left to cool and harden for two weeks. After hardening, it was cut into smaller cakes. Aromatic herbs were often added to the rendered soap to impart their fragrance, such as yarrow leaves, lavender , germander , etc. A detergent similar to soap
3723-405: The corresponding salts. For example, when sodium hydroxide reacts with hydrochloric acid , sodium chloride is formed: In general, such neutralization reactions are represented by one simple net ionic equation: This type of reaction with a strong acid releases heat, and hence is exothermic . Such acid–base reactions can also be used for titrations . However, sodium hydroxide is not used as
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#17328632229863796-404: The end of the stages. In a similar fashion, sodium hydroxide is used to digest tissues, as in a process that was used with farm animals at one time. This process involved placing a carcass into a sealed chamber, then adding a mixture of sodium hydroxide and water (which breaks the chemical bonds that keep the flesh intact). This eventually turns the body into a liquid with a dark brown color, and
3869-535: The limited solubility of sodium hydroxide in organic solvents means that the more soluble potassium hydroxide (KOH) is often preferred. Touching a sodium hydroxide solution with bare hands, while not recommended, produces a slippery feeling. This happens because oils on the skin such as sebum are converted to soap. Despite solubility in propylene glycol it is unlikely to replace water in saponification due to propylene glycol's primary reaction with fat before reaction between sodium hydroxide and fat. Sodium hydroxide
3942-432: The market, making the process of cleaning things other than skin, such as clothing, floors, and bathrooms, much easier. Liquid soap also works better for more traditional or non-machine washing methods, such as using a washboard . Sodium hydroxide Sodium hydroxide is a highly corrosive base and alkali that decomposes lipids and proteins at ambient temperatures and may cause severe chemical burns . It
4015-431: The metastable ones NaOH·3H 2 O and NaOH·4H 2 O (β) can be crystallized from solutions of the proper composition, as listed above. However, solutions of NaOH can be easily supercooled by many degrees, which allows the formation of hydrates (including the metastable ones) from solutions with different concentrations. For example, when a solution of NaOH and water with 1:2 mole ratio (52.6% NaOH by mass)
4088-453: The milder soaps used by the Gauls around 58 BC. Aretaeus of Cappadocia , writing in the 2nd century AD, observes among "Celts, which are men called Gauls, those alkaline substances that are made into balls [...] called soap ". The Romans' preferred method of cleaning the body was to massage oil into the skin and then scrape away both the oil and any dirt with a strigil . The standard design
4161-569: The newly formed Society of Soapmakers a monopoly in soap production who produced certificates from 'foure Countesses, and five Viscountesses, and divers other Ladies and Gentlewomen of great credite and quality, besides common Laundresses and others', testifying that 'the New White Soap washeth whiter and sweeter than the Old Soap'. During the Restoration era (February 1665 – August 1714) a soap tax
4234-422: The only solids that remain are bone hulls, which can be crushed between one's fingertips. Sodium hydroxide is frequently used in the process of decomposing roadkill dumped in landfills by animal disposal contractors. Due to its availability and low cost, it has been used by criminals to dispose of corpses. Italian serial killer Leonarda Cianciulli used this chemical to turn dead bodies into soap. In Mexico,
4307-504: The poster-girl for Pears soap, making her the first celebrity to endorse a commercial product. William Gossage produced low-priced, good-quality soap from the 1850s. Robert Spear Hudson began manufacturing a soap powder in 1837, initially by grinding the soap with a mortar and pestle . American manufacturer Benjamin T. Babbitt introduced marketing innovations that included the sale of bar soap and distribution of product samples . William Hesketh Lever and his brother, James , bought
4380-625: The products the stewards of royal estates are to tally. The lands of Medieval Spain were a leading soapmaker by 800, and soapmaking began in the Kingdom of England about 1200. Soapmaking is mentioned both as "women's work" and as the produce of "good workmen" alongside other necessities, such as the produce of carpenters, blacksmiths, and bakers. In Europe, soap in the 9th century was produced from animal fats and had an unpleasant smell. This changed when olive oil began to be used in soap formulas instead, after which much of Europe's soap production moved to
4453-516: The reactivity of alkali metals in academic environments; however, it is not used commercially aside from a reaction within the mercury cell chloralkali process where sodium amalgam is reacted with water. Sodium hydroxide is a popular strong base used in industry. Sodium hydroxide is used in the manufacture of sodium salts and detergents, pH regulation, and organic synthesis. In bulk, it is most often handled as an aqueous solution , since solutions are cheaper and easier to handle. Sodium hydroxide
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#17328632229864526-549: The repeated laundering of materials used in perfume -making lead to noticeable amounts of soap forming. This fits with other evidence from Mesopotamian culture. Pliny the Elder, whose writings chronicle life in the first century AD, describes soap as "an invention of the Gauls". The word sapo , Latin for soap, has connected to a mythical Mount Sapo, a hill near the River Tiber where animals were sacrificed. But in all likelihood,
4599-434: The simplest hydroxides, sodium hydroxide is frequently used alongside neutral water and acidic hydrochloric acid to demonstrate the pH scale to chemistry students. Sodium hydroxide is used in many industries: in the making of wood pulp and paper , textiles , drinking water , soaps and detergents , and as a drain cleaner . Worldwide production in 2022 was approximately 83 million tons. Pure sodium hydroxide
4672-506: The solution alkaline, which aluminium can dissolve in. Sodium aluminate is an inorganic chemical that is used as an effective source of aluminium hydroxide for many industrial and technical applications. Pure sodium aluminate (anhydrous) is a white crystalline solid having a formula variously given as NaAlO 2 , Na 3 AlO 3 , Na[Al(OH) 4 ] , Na 2 O·Al 2 O 3 or Na 2 Al 2 O 4 . Formation of sodium tetrahydroxoaluminate(III) or hydrated sodium aluminate
4745-560: The space groups Cmcm ( oS8 ) and Pbca (oP24), respectively. The monohydrate cell dimensions are a = 1.1825, b = 0.6213, c = 0.6069 nm . The atoms are arranged in a hydrargillite -like layer structure, with each sodium atom surrounded by six oxygen atoms, three each from hydroxide ions and three from water molecules. The hydrogen atoms of the hydroxyls form strong bonds with oxygen atoms within each O layer. Adjacent O layers are held together by hydrogen bonds between water molecules. Sodium hydroxide reacts with protic acids to produce water and
4818-518: The use of soap has become commonplace in industrialized nations due to a better understanding of the role of hygiene in reducing the population size of pathogenic microorganisms . Until the Industrial Revolution , soapmaking was conducted on a small scale and the product was rough. In 1780, James Keir established a chemical works at Tipton , for the manufacture of alkali from the sulfates of potash and soda, to which he afterwards added
4891-399: The white liquor solution used to separate lignin from cellulose fibers in the kraft process . It also plays a key role in several later stages of the process of bleaching the brown pulp resulting from the pulping process. These stages include oxygen delignification, oxidative extraction, and simple extraction, all of which require a strong alkaline environment with a pH > 10.5 at
4964-635: The word was borrowed from an early Germanic language and is cognate with Latin sebum , " tallow ". It first appears in Pliny the Elder 's account, Historia Naturalis , which discusses the manufacture of soap from tallow and ashes. There he mentions its use in the treatment of scrofulous sores , as well as among the Gauls as a dye to redden hair which the men in Germania were more likely to use than women. The Romans avoided washing with harsh soaps before encountering
5037-403: Was concentrated in a few centers of Provence — Toulon , Hyères , and Marseille —which supplied the rest of France. In Marseilles, by 1525, production was concentrated in at least two factories, and soap production at Marseille tended to eclipse the other Provençal centers. English manufacture tended to concentrate in London. The demand for high-quality hard soap was significant enough during
5110-712: Was estimated at 51 million tonnes. In 1998, total world production was around 45 million tonnes . North America and Asia each contributed around 14 million tonnes, while Europe produced around 10 million tonnes. In the United States, the major producer of sodium hydroxide is Olin , which has annual production around 5.7 million tonnes from sites at Freeport, Texas ; Plaquemine, Louisiana ; St. Gabriel, Louisiana ; McIntosh, Alabama ; Charleston, Tennessee ; Niagara Falls, New York ; and Bécancour, Canada . Other major US producers include Oxychem , Westlake , Shintek, and Formosa . All of these companies use
5183-464: Was introduced in England, which meant that until the mid-1800s, soap was a luxury, used regularly only by the well-to-do. The soap manufacturing process was closely supervised by revenue officials who made sure that soapmakers' equipment was kept under lock and key when not being supervised. Moreover, soap could not be produced by small makers because of a law that stipulated that soap boilers must manufacture
5256-472: Was manufactured in ancient China from the seeds of Gleditsia sinensis . Another traditional detergent is a mixture of pig pancreas and plant ash called zhuyizi ( simplified Chinese : 猪胰子 ; traditional Chinese : 豬胰子 ; pinyin : zhūyízǐ ). Soap made of animal fat did not appear in China until the modern era. Soap-like detergents were not as popular as ointments and creams. Hard toilet soap with
5329-462: Was produced using olive oil together with alkali and lime . Soap was exported from Syria to other parts of the Muslim world and to Europe. A 12th-century document describes the process of soap production. It mentions the key ingredient, alkali , which later became crucial to modern chemistry, derived from al-qaly or "ashes". By the 13th century, the manufacture of soap in the Middle East had become
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