"Oil of vitriol" and "sulphuric acid" redirect here. For sweet oil of vitriol, seediethyl ether. For the novel by Amélie Nothomb, seeSulphuric Acid (novel).
Pure sulfuric acid does not occur naturally due to itsstrong affinity to water vapor; it ishygroscopic and readily absorbswater vapor from theair.[7] Concentrated sulfuric acid is a strong oxidant with powerful dehydrating properties, making it highly corrosive towards other materials, from rocks to metals.Phosphorus pentoxide is a notable exception in that it is not dehydrated by sulfuric acid but, to the contrary, dehydrates sulfuric acid tosulfur trioxide. Upon addition of sulfuric acid to water, a considerable amount of heat is released; thus, the reverse procedure of adding water to the acid is generally avoided since the heat released may boil the solution, spraying droplets of hot acid during the process. Upon contact with body tissue, sulfuric acid can cause severeacidicchemical burns and secondarythermal burns due to dehydration.[8][9] Dilute sulfuric acid is substantially less hazardous without the oxidative and dehydrating properties; though, it is handled with care for its acidity.
Although nearly 100% sulfuric acid solutions can be made, the subsequent loss ofSO3 at the boiling point brings the concentration to 98.3% acid. The 98.3% grade, which is more stable in storage, is the usual form of what is described as "concentrated sulfuric acid". Other concentrations are used for different purposes. Some common concentrations are:[13][14]
"Chamber acid" and "tower acid" were the two concentrations of sulfuric acid produced by thelead chamber process, chamber acid being the acid produced in the lead chamber itself (<70% to avoid contamination withnitrosylsulfuric acid) and tower acid being the acid recovered from the bottom of the Glover tower.[13][14] They are now obsolete as commercial concentrations of sulfuric acid, although they may be prepared in the laboratory from concentrated sulfuric acid if needed. In particular, "10 M" sulfuric acid (the modern equivalent of chamber acid, used in manytitrations) is prepared by slowly adding 98% sulfuric acid to an equal volume of water, with good stirring: the temperature of the mixture can rise to 80 °C (176 °F) or higher.[14]
Sulfuric acid is a colorless oily liquid, and has a vapor pressure of <0.001 mmHg at 25 °C and 1 mmHg at 145.8 °C,[16] and 98% sulfuric acid has a vapor pressure of <1 mmHg at 40 °C.[17]
In the solid state, sulfuric acid is a molecular solid that formsmonoclinic crystals with nearly trigonal lattice parameters. The structure consists of layers parallel to the (010) plane, in which each molecule is connected byhydrogen bonds to two others.[3]HydratesH2SO4·nH2O are known forn = 1, 2, 3, 4, 6.5, and 8, although most intermediate hydrates are stable againstdisproportionation.[18]
In spite of the viscosity of the acid, the effectiveconductivities of theH3SO+4 andHSO−4 ions are high due to an intramolecular proton-switch mechanism (analogous to theGrotthuss mechanism in water), making sulfuric acid a good conductor of electricity. It is also an excellent solvent for many reactions.
An experiment that demonstrates the dehydration properties of concentrated sulfuric acid. When concentrated sulfuric acid comes into contact withsucrose, slow carbonification of the sucrose takes place. The reaction is accompanied by the evolution of gaseous products that contribute to the formation of the foamy carbon pillar that rises above thebeaker.Drops of concentrated sulfuric acid rapidly decompose a piece of cotton towel by dehydration.
Concentrated sulfuric acid has a powerfuldehydrating property, removingwater (H2O) from other chemical compounds such astable sugar (sucrose) and othercarbohydrates, to producecarbon,steam, and heat. Dehydration of table sugar (sucrose) is a common laboratory demonstration.[21] The sugar darkens as carbon is formed, and a rigid column of black, porous carbon called acarbon snake may emerge.[22]
Similarly, mixingstarch into concentrated sulfuric acid gives elemental carbon and water. The effect of this can also be seen when concentrated sulfuric acid is spilled on paper. Paper is composed ofcellulose, apolysaccharide related to starch. The cellulose reacts to give a burnt appearance in which the carbon appears much likesoot that results from fire.Although less dramatic, the action of the acid oncotton, even in diluted form, destroys the fabric.
The reaction withcopper(II) sulfate can also demonstrate the dehydration property of sulfuric acid. The blue crystals change into white powder as water is removed.
Sulfuric acid reacts with mostbases to give the corresponding sulfate or bisulfate.
Aluminium sulfate, also known as paper maker's alum, is made by treatingbauxite with sulfuric acid:
2 AlO(OH) + 3 H2SO4 → Al2(SO4)3 + 4 H2O
Sulfuric acid can also be used to displace weaker acids from their salts. Reaction withsodium acetate, for example, displacesacetic acid,CH3COOH, and formssodium bisulfate:
Solid state structure of the[D3SO4]+ ion present in[D3SO4]+[SbF6]−, synthesized by usingDF in place of HF.
When allowed to react withsuperacids, sulfuric acid can act as a base and can be protonated, forming the[H3SO4]+ ion. Salts of[H3SO4]+ have been prepared (e.g. trihydroxyoxosulfonium hexafluoroantimonate(V)[H3SO4]+[SbF6]−) using the following reaction in liquidHF:
The above reaction is thermodynamically favored due to the highbond enthalpy of the Si–F bond in the side product. Protonation using simplyfluoroantimonic acid, however, has met with failure, as pure sulfuric acid undergoesself-ionization to give[H3O]+ ions:
2 H2SO4 ⇌ H3O+ + HS2O−7
which prevents the conversion ofH2SO4 to[H3SO4]+ by the HF/SbF5 system.[23]
The compounds of sulfur andiodine are recovered and reused, hence the process is called thesulfur–iodine cycle. This process isendothermic and must occur at high temperatures, so energy in the form of heat has to be supplied. The sulfur–iodine cycle has been proposed as a way to supply hydrogen for ahydrogen-based economy. It is an alternative toelectrolysis, and does not requirehydrocarbons like current methods ofsteam reforming. But note that all of the available energy in the hydrogen so produced is supplied by the heat used to make it.[26][27]
Sulfuric acid is rarely encountered naturally on Earth inanhydrous form, due to its greataffinity for water. Dilute sulfuric acid is a constituent ofacid rain, which is formed by atmosphericoxidation ofsulfur dioxide in the presence ofwater—i.e. oxidation ofsulfurous acid. When sulfur-containing fuels such as coal or oil are burned, sulfur dioxide is the main byproduct (besides the chief products carbon oxides and water).
Sulfuric acid is formed naturally by the oxidation of sulfide minerals, such aspyrite:
When iron(III) oxidation of pyrite occurs, the process can become rapid.pH values below zero have been measured in ARD produced by this process.
ARD can also produce sulfuric acid at a slower rate, so that theacid neutralizing capacity (ANC) of the aquifer can neutralize the produced acid. In such cases, thetotal dissolved solids (TDS) concentration of the water can be increased from the dissolution of minerals from the acid-neutralization reaction with the minerals.
Sulfuric acid is used as a defense by certain marine species, for example, the phaeophyte algaDesmarestia munda (orderDesmarestiales) concentrates sulfuric acid in cell vacuoles.[28]
In thestratosphere, the atmosphere's second layer that is generally between 10 and 50 km above Earth's surface, sulfuric acid is formed by the oxidation of volcanic sulfur dioxide by thehydroxyl radical:[29]
SO2 + HO• → HSO3
HSO3 + O2 → SO3 + HO2
SO3 + H2O → H2SO4
Because sulfuric acid reachessupersaturation in the stratosphere, it can nucleate aerosol particles and provide a surface for aerosol growth via condensation and coagulation with other water-sulfuric acid aerosols. This results in the stratospheric aerosol layer.[29]
The permanentVenusian clouds produce a concentrated acid rain, as the clouds in the atmosphere of Earth produce water rain.[30] Sulfuric acid ice has been detected onJupiter's moonEuropa, where it forms when sulfur ions fromJupiter's magnetosphere implant into the icy surface.[31]
In the first step, sulfur is burned to produce sulfur dioxide.
S(s) + O2 → SO2
The sulfur dioxide is oxidized to sulfur trioxide by oxygen in the presence of avanadium(V) oxidecatalyst. This reaction is reversible and the formation of the sulfur trioxide is exothermic.
2 SO2 + O2 ⇌ 2 SO3
The sulfur trioxide is absorbed into 97–98%H2SO4 to formoleum (H2S2O7), also known as fuming sulfuric acid or pyrosulphuric acid. The oleum is then diluted with water to form concentrated sulfuric acid.
Directly dissolvingSO3 in water, called the "wet sulfuric acid process", is rarely practiced because the reaction is extremely exothermic, resulting in a hot aerosol of sulfuric acid that requires condensation and separation.
In the first step, sulfur is burned to produce sulfur dioxide:
S + O2 → SO2 (−297 kJ/mol)
or, alternatively,hydrogen sulfide (H2S) gas is incinerated toSO2 gas:
Burningsulfur together with saltpeter (potassium nitrate,KNO3), in the presence of steam, has been used historically. As saltpeter decomposes, it oxidizes the sulfur toSO3, which combines with water to produce sulfuric acid.
Prior to 1900, most sulfuric acid was manufactured by thelead chamber process.[32] As late as 1940, up to 50% of sulfuric acid manufactured in the United States was produced by chamber process plants.
A wide variety of laboratory syntheses are known, and typically begin fromsulfur dioxide or an equivalentsalt. In the metabisulfite method,hydrochloric acid reacts withmetabisulfite to producesulfur dioxide vapors. The gas is bubbled throughnitric acid, which will release brown/red vapors ofnitrogen dioxide as the reaction proceeds. The completion of the reaction is indicated by the ceasing of the fumes. This method conveniently does not produce an inseparable mist.[citation needed]
3 SO2 + 2 HNO3 + 2 H2O → 3 H2SO4 + 2 NO
Alternatively, dissolving sulfur dioxide in an aqueous solution of an oxidizing metal salt such as copper(II) or iron(III) chloride:[citation needed]
2 FeCl3 + 2 H2O + SO2 → 2 FeCl2 + H2SO4 + 2 HCl
2 CuCl2 + 2 H2O + SO2 → 2 CuCl + H2SO4 + 2 HCl
Two less well-known laboratory methods of producing sulfuric acid, albeit in dilute form and requiring some extra effort in purification, rely onelectrolysis. A solution ofcopper(II) sulfate can be electrolyzed with a copper cathode and platinum/graphite anode to give spongycopper at cathode and oxygen gas at the anode. The solution of dilute sulfuric acid indicates completion of the reaction when it turns from blue to clear (production of hydrogen at cathode is another sign):[citation needed]
2 CuSO4 + 2 H2O → 2 Cu + 2 H2SO4 + O2
More costly, dangerous, and troublesome is the electrobromine method, which employs a mixture ofsulfur, water, andhydrobromic acid as the electrolyte. The sulfur is pushed to bottom of container under the acid solution. Then the copper cathode and platinum/graphite anode are used with the cathode near the surface and the anode is positioned at the bottom of the electrolyte to apply the current. This may take longer and emits toxicbromine/sulfur-bromide vapors, but the reactant acid is recyclable. Overall, only the sulfur and water are converted to sulfuric acid and hydrogen (omitting losses of acid as vapors):[citation needed]
Sulfuric acid is a very important commodity chemical, and a nation's sulfuric acid production was as recently as 2002 believed to be a good indicator of its industrial strength.[33] World production in the year 2004 was about 180 milliontonnes, with the following geographic distribution: Asia 35%, North America (including Mexico) 24%, Africa 11%, Western Europe 10%, Eastern Europe and Russia 10%, Australia and Oceania 7%, South America 7%.[34] World production in 2022 was estimated at 260 million tonnes.[35]
As of the late 20th century, most of the produced amount (≈60%) was consumed for fertilizers, particularly superphosphates, ammonium phosphate and ammonium sulfates. About 20% is used in chemical industry for production of detergents, synthetic resins, dyestuffs, pharmaceuticals, petroleum catalysts, insecticides andantifreeze, as well as in various processes such as oil well acidicizing, aluminium reduction, paper sizing, and water treatment. About 6% of uses are related topigments and include paints,enamels, printing inks, coated fabrics and paper, while the rest is dispersed into a multitude of applications such as production of explosives,cellophane, acetate and viscose textiles, lubricants,non-ferrous metals, and batteries.[36]
The dominant use for sulfuric acid is in the "wet method" for the production ofphosphoric acid, used for manufacture ofphosphatefertilizers. In this method, phosphate rock is used, and more than 100 million tonnes are processed annually. This raw material is shown below asfluorapatite, though the exact composition may vary. This is treated with 93% sulfuric acid to producecalcium sulfate,hydrogen fluoride (HF) andphosphoric acid. The HF is removed ashydrofluoric acid. The overall process can be represented as:
Ammonium sulfate, an important nitrogen fertilizer, is most commonly produced as a byproduct fromcoking plants supplying the iron and steel making plants. Reacting theammonia produced in the thermal decomposition ofcoal with waste sulfuric acid allows the ammonia to be crystallized out as a salt (often brown because of iron contamination) and sold into the agro-chemicals industry.
Sulfuric acid is also important in the manufacture ofdyestuffs solutions.
Sulfuric acid is used insteelmaking and othermetallurgical industries as apickling agent for removal ofrust andfouling.[37] Used acid is often recycled using a spent acid regeneration (SAR) plant. These plants combust spent acid[clarification needed] with natural gas, refinery gas, fuel oil or other fuel sources. This combustion process produces gaseoussulfur dioxide (SO2) andsulfur trioxide (SO3) which are then used to manufacture "new" sulfuric acid.
Hydrogen peroxide (H2O2) can be added to sulfuric acid to producepiranha solution, a powerful but potentially hazardous cleaning solution with which substrate surfaces can be cleaned. Piranha solution is typically used in the microelectronics industry, and also in laboratory settings to clean glassware.
Sulfuric acid is used for a variety of other purposes in the chemical industry. For example, it is the usual acid catalyst for the conversion ofcyclohexanone oxime tocaprolactam, used for makingnylon. It is used for makinghydrochloric acid fromsalt via theMannheim process. MuchH2SO4 is used inpetroleum refining, for example as a catalyst for the reaction ofisobutane withisobutylene to giveisooctane, a compound that raises theoctane rating ofgasoline (petrol). Sulfuric acid is also often used as a dehydrating or oxidizing agent in industrial reactions, such as the dehydration of various sugars to form solid carbon.
Domestic acidic drain cleaners usually contain sulfuric acid at a high concentration which turns a piece ofpH paper red and chars it instantly, demonstrating both the strong acidic nature and dehydrating property.
Sulfuric acid acts as the electrolyte inlead–acid batteries (lead-acid accumulator):
Sulfuric acid at high concentrations is frequently the major ingredient indomestic acidic drain cleaners[12] which are used to removelipids,hair,tissue paper, etc. Similar to theiralkaline versions, such drain openers can dissolve fats and proteins viahydrolysis. Moreover, as concentrated sulfuric acid has a strong dehydrating property, it can remove tissue paper via dehydrating process as well. Since the acid may react with water vigorously, such acidic drain openers should be added slowly into the pipe to be cleaned.
The study ofvitriols (hydratedsulfates of various metals forming glassy minerals from which sulfuric acid can be derived) began inancient times.Sumerians had a list of types of vitriol that they classified according to the substances' color. Some of the earliest discussions on the origin and properties of vitriol is in the works of the Greek physicianDioscorides (first century AD) and the Roman naturalistPliny the Elder (23–79 AD).Galen also discussed its medical use. Metallurgical uses for vitriolic substances were recorded in the Hellenistic alchemical works ofZosimos of Panopolis, in the treatisePhisica et Mystica, and theLeyden papyrus X.[38]Medieval Islamic alchemists like the authors writing under the name ofJabir ibn Hayyan (died c. 806 – c. 816, known in Latin as Geber),Abu Bakr al-Razi (865–925, known in Latin as Rhazes),Ibn Sina (980–1037, known in Latin as Avicenna), andMuhammad ibn Ibrahim al-Watwat (1234–1318) included vitriol in their mineral classification lists.[39]
Jabir ibn Hayyan, Abu Bakr al-Razi, Ibn Sina, et al.
The Jabirian authors and al-Razi experimented extensively with the distillation of various substances, including vitriols.[40] In one recipe recorded in hisKitāb al-Asrār ('Book of Secrets'), al-Razi may have created sulfuric acid without being aware of it:[41]
Take white (Yemeni)alum, dissolve it and purify it by filtration. Then distil (green?) vitriol with copper-green (the acetate), and mix (the distillate) with the filtered solution of the purified alum, afterwards let it solidify (or crystallise) in the glass beaker. You will get the best qalqadis (white alum) that may be had.[42]
— Abu Bakr al-Razi,Kitāb al-Asrār
In an anonymous Latin work variously attributed toAristotle (under the titleLiber Aristotilis, 'Book of Aristotle'),[43] to al-Razi (under the titleLumen luminum magnum, 'Great Light of Lights'), or to Ibn Sina,[44] the author speaks of an 'oil' (oleum) obtained through the distillation ofiron(II) sulfate (green vitriol), which was likely 'oil of vitriol' or sulfuric acid.[45] The work refers multiple times to Jabir ibn Hayyan'sSeventy Books (Liber de septuaginta), one of the few Arabic Jabir works that were translated into Latin.[46] The author of the version attributed to al-Razi also refers to theLiber de septuaginta as his own work, showing that he erroneously believed theLiber de septuaginta to be a work by al-Razi.[47] There are several indications that the anonymous work was an original composition in Latin,[48] although according to one manuscript it was translated by a certain Raymond of Marseilles, meaning that it may also have been a translation from the Arabic.[49]
According toAhmad Y. al-Hassan, three recipes for sulfuric acid occur in an anonymousGarshuni manuscript containing a compilation taken from several authors and dating from beforec. 1100 AD.[50] One of them runs as follows:
The water of vitriol and sulphur which is used to irrigate the drugs: yellow vitriol three parts, yellow sulphur one part, grind them and distil them in the manner of rose-water.[51]
A recipe for the preparation of sulfuric acid is mentioned inRisālat Jaʿfar al-Sādiq fī ʿilm al-ṣanʿa, an Arabic treatise falsely attributed to the Shi'i ImamJa'far al-Sadiq (died 765).Julius Ruska dated this treatise to the 13th century, but according to Ahmad Y. al-Hassan it likely dates from an earlier period:[52]
Then distil green vitriol in a cucurbit and alembic, using medium fire; take what you obtain from the distillate, and you will find it clear with a greenish tint.[51]
Vincent of Beauvais, Albertus Magnus, and pseudo-Geber
Sulfuric acid was called 'oil of vitriol' by medieval European alchemists because it was prepared by roasting iron(II) sulfate or green vitriol in an ironretort. The first allusions to it in works that are European in origin appear in the thirteenth century AD, as for example in the works ofVincent of Beauvais, in theCompositum de Compositis ascribed toAlbertus Magnus, and inpseudo-Geber'sSumma perfectionis.[53]
A method of producingoleum sulphuris per campanam, or "oil of sulfur by the bell", was known by the 16th century: it involved burning sulfur under a glass bell in moist weather (or, later, under a moistened bell). However, it was very inefficient (according toGesner, 5 pounds (2.3 kg) of sulfur converted into less than 1 ounce (0.03 kg) of acid), and the resulting product was contaminated bysulfurous acid (or rather, solution ofsulfur dioxide) so most alchemists (including, for example, Isaac Newton) did not consider it equivalent to "oil of vitriol".
In the 17th century,Johann Rudolf Glauber discovered that adding saltpeter (potassium nitrate,KNO3) significantly improves the output, also replacing moisture with steam. As saltpeter decomposes, it oxidizes the sulfur toSO3, which combines with water to produce sulfuric acid. In 1736,Joshua Ward, a London pharmacist, used this method to begin the first large-scale production of sulfuric acid.
In 1746 in Birmingham,John Roebuck adapted this method to produce sulfuric acid inlead-lined chambers, which were stronger, less expensive, and could be made larger than the previously used glass containers. This process allowed the effective industrialization of sulfuric acid production. After several refinements, this method, called thelead chamber process or "chamber process", remained the standard for sulfuric acid production for almost two centuries with a purity of 62% and a conversion of 75%.[4]
Sulfuric acid created by John Roebuck's process approached a 65% concentration. Later refinements to the lead chamber process by French chemistJoseph Louis Gay-Lussac and British chemist John Glover improved concentration to 78%. However, the manufacture of somedyes and other chemical processes require a more concentrated product. Throughout the 18th century, this could only be made bydry distilling minerals in a technique similar to the originalalchemical processes.Pyrite (iron disulfide,FeS2) was heated in air to yield iron(II) sulfate,FeSO4, which was oxidized by further heating in air to formiron(III) sulfate,Fe2(SO4)3, which, when heated to 480 °C, decomposed toiron(III) oxide and sulfur trioxide, which could be passed through water to yield sulfuric acid in any concentration. However, the expense of this process prevented the large-scale use of concentrated sulfuric acid.[4]
In 1831, Britishvinegar merchant Peregrine Phillips patented thecontact process, which was a far more economical process for producing sulfur trioxide and concentrated sulfuric acid. Today, nearly all of the world's sulfuric acid is produced using this method.[33]
In the early to mid 19th century "vitriol" plants existed, among other places, inPrestonpans in Scotland,Shropshire and theLagan Valley inCounty Antrim,Northern Ireland, where it was used as a bleach for linen. Early bleaching of linen was done using lactic acid from sour milk but this was a slow process and the use of vitriol sped up the bleaching process.[54]
Drops of 98% sulfuric acid char a piece of tissue paper instantly. Carbon is left after the dehydration reaction, staining the paper black.Nitrile glove exposed to drops of 98% sulfuric acid for 10 minutesSuperficial chemical burn caused by two 98% sulfuric acid splashes (forearm skin)
Sulfuric acid must be stored carefully in containers made of nonreactive material (such as glass). Solutions equal to or stronger than 1.5 M are labeled "CORROSIVE", while solutions greater than 0.5 M but less than 1.5 M are labeled "IRRITANT". However, even the normal laboratory "dilute" grade (approximately 1 M, 10%) will char paper if left in contact for a sufficient time.[citation needed]
The standard first aid treatment for acid spills on the skin is, as for othercorrosive agents, irrigation with large quantities of water. Washing is continued for at least ten to fifteen minutes to cool the tissue surrounding the acid burn and to prevent secondary damage. Contaminated clothing is removed immediately and the underlying skin washed thoroughly.[citation needed]
Preparation of diluted acid can be dangerous due to the heat released in the dilution process. To avoid splattering, the concentrated acid is usually added to water and not the other way around. A saying used to remember this is "Do like you oughta, add the acid to the water".[55][better source needed][56] Water has a higher heat capacity than the acid, and so a vessel of cold water will absorb heat as acid is added.
Also, because the acid is denser than water, it sinks to the bottom. Heat is generated at the interface between acid and water, which is at the bottom of the vessel. Acid will not boil, because of its higher boiling point. Warm water near the interface rises due toconvection, which cools the interface, and prevents boiling of either acid or water.
In contrast, addition of water to concentrated sulfuric acid results in a thin layer of water on top of the acid. Heat generated in this thin layer of water can boil, leading to the dispersal of a sulfuric acidaerosol, or worse, anexplosion.
Preparation of solutions greater than 6 M (35%) in concentration is dangerous, unless the acid is added slowly enough to allow the mixture sufficient time to cool. Otherwise, the heat produced may be sufficient to boil the mixture. Efficient mechanical stirring and external cooling (such as an ice bath) are essential.
Reaction rates double for about every 10-degree Celsiusincrease in temperature.[57][ISBN missing] Therefore, the reaction will become more violent as dilution proceeds, unless the mixture is given time to cool. Adding acid to warm water will cause a violent reaction.
On a laboratory scale, sulfuric acid can be diluted by pouring concentrated acid onto crushed ice made from de-ionized water. The ice melts in an endothermic process while dissolving the acid. The amount of heat needed to melt the ice in this process is greater than the amount of heat evolved by dissolving the acid so the solution remains cold.[58] After all the ice has melted, further dilution can take place using water.
The main occupational risks posed by this acid are skin contact leading to burns (see above) and the inhalation of aerosols. Exposure to aerosols at high concentrations leads to immediate and severe irritation of the eyes, respiratory tract and mucous membranes: this ceases rapidly after exposure, although there is a risk of subsequentpulmonary edema if tissue damage has been more severe. At lower concentrations, the most commonly reported symptom of chronic exposure to sulfuric acid aerosols is erosion of the teeth, found in virtually all studies: indications of possible chronic damage to therespiratory tract are inconclusive as of 1997. Repeated occupational exposure to sulfuric acid mists may increase the chance of lung cancer by up to 64 percent.[59] In the United States, thepermissible exposure limit (PEL) for sulfuric acid is fixed at 1 mg/m3: limits in other countries are similar. There have been reports of sulfuric acid ingestion leading tovitamin B12 deficiency with subacute combined degeneration. The spinal cord is most often affected in such cases, but the optic nerves may showdemyelination, loss ofaxons andgliosis.
^abKemnitz, E.; Werner, C.; Trojanov, S. (15 November 1996). "Reinvestigation of Crystalline Sulfuric Acid and Oxonium Hydrogensulfate".Acta Crystallographica Section C Crystal Structure Communications.52 (11):2665–2668.Bibcode:1996AcCrC..52.2665K.doi:10.1107/S0108270196006749.
^abcdZumdahl, Steven S. (2009).Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23.ISBN978-0-618-94690-7.
^"Sulfuric acid"(PDF).Determination of Noncancer Chronic Reference Exposure Levels Batch 2B December 2001. 2001. Archived fromthe original(PDF) on 22 May 2003. Retrieved1 October 2012.
^Giauque, W. F.; Hornung, E. W.; Kunzler, J. E.; Rubin, T. R. (January 1960). "The Thermodynamic Properties of Aqueous Sulfuric Acid Solutions and Hydrates from 15 to 300K. 1".Journal of the American Chemical Society.82 (1):62–70.Bibcode:1960JAChS..82...62G.doi:10.1021/ja01486a014.
^Housecroft, Catherine E.; Sharpe, Alan G. (2008). "Chapter 16: The group 16 elements".Inorganic Chemistry, 3rd Edition. Pearson. p. 523.ISBN978-0-13-175553-6.
^Jones, Edward M. (1950). "Chamber Process Manufacture of Sulfuric Acid".Industrial and Engineering Chemistry.42 (11):2208–2210.doi:10.1021/ie50491a016.
Needham, Joseph; Ping-Yü, Ho; Gwei-Djen, Lu; Sivin, Nathan (1980).Science and Civilisation in China. Vol. 5: Chemistry and Chemical Technology. Cambridge: Cambridge University Press. Part IV, Spagyrical Discovery and Invention: Apparatus, Theories and Gifts; p. 195, note d.ISBN978-0-521-08573-1.
Stapleton, Henry E.; Azo, R. F.; Hidayat Husain, M. (1927)."Chemistry in Iraq and Persia in the Tenth Century A.D."Memoirs of the Asiatic Society of Bengal.VIII (6). p. 333 (on theLiber Bubacaris, cf. p. 369, note 3), 393. Quote from p. 393: "It is extremely curious to see how close ar-Rāzī came to the discovery of Sulphuric acid, without actually recognising the powerful solvent properties of the distillate of vitriols and alum. This is all the more surprising, as he fully realised the reactive powers of both Arsenic sulphide and Sal-ammoniac, the 'Spirits' with which he must have associated the distillate from alum".OCLC706947607.
Hoefer 1866, p. 343 still firmly believed that the work belonged to al-Razi, but this view has been abandoned ever since the studies done byRuska 1939; cf.Moureau 2020, p. 117: "although many alchemical Latin texts are attributed to Rāzı̄, only one is, in the current state of research, known to be a translation of the famous physician and alchemist" (i.e., theLiber secretorum Bubacaris, a paraphrase of al-Razi'sKitāb al-asrār)
Ferrario, Gabriele (2009). "An Arabic Dictionary of Technical Alchemical Terms: MS Sprenger 1908 of the Staatsbibliothek zu Berlin (fols. 3r–6r)".Ambix.56 (1): 42.doi:10.1179/174582309X405219.PMID19831258.S2CID41045827.A strong and yet to be refuted critique of this traditional attribution was proposed by Ruska [...]
^Al-Hassan 2001, pp. 60, 63. On the dating of this manuscript, see alsoBerthelot, Marcellin; Houdas, Octave V. (1893).La Chimie au Moyen Âge (in French). Paris: Imprimerie nationale. vol. II, p. xvii.
^Benninga, H. (1990).A history of lactic acid making: a chapter in the history of biotechnology. Dordrecht, Netherlands: Kluwer Academic. p. 4.ISBN9780792306252.OCLC20852966.
^Beaumont, J. J.; Leveton, J.; Knox, K.; Bloom, T.; McQuiston, Tm; Young, M.; Goldsmith, R.; Steenland, N. K.; Brown, D. P.; Halperin, W. E. (1987). "Lung cancer mortality in workers exposed to sulfuric acid mist and other acid mists".J Natl Cancer Inst.79 (5):911–21.doi:10.1093/jnci/79.5.911.PMID3479642.
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