Sulfuric Acid: Formula, Properties, Structure and Uses

He sulfuric acid (H ₂ SW ₄₎ Is perhaps the most important of all heavy industrial chemicals. The consumption of sulfuric acid has often been cited as an indicator of the overall state of a nation's economy.

Sulfuric acid is an oily, colorless liquid, soluble in water with heat release and corrosive to metals and fabrics. It carbonizes wood and most of the organic matter on contact with it, but is unlikely to cause a fire.

96% Extra pure sulfuric acid

Prolonged exposure to low concentrations or short-term exposure to high concentrations may result in adverse health effects.

By far the most important use of sulfuric acid is in the phosphate fertilizer industry. Other important applications of sulfuric acid are found in petroleum refining, pigment production, steel pickling, non-ferrous metal mining and the manufacture of explosives, detergents, plastics, man-made fibers and pharmaceuticals.

Vitriol, the precursor of sulfuric acid

In medieval Europe sulfuric acid was known as vitriol, vitriol oil or vitriol liqueur by the alchemists. It was considered the most important chemical substance, and was intended to be used as a philosopher's stone.

Skeletal formula of sulfuric acid

The Sumerians already had a list of several types of vitriol. Galen (possibly the most renowned of all doctors of antiquity), Dioscorides (Greek physician of the first century AD), and Pliny the Elder (Roman naturalist who lived between AD 23-79) discussed his medical use.

Left:"The Alchemist, in Search of the Philosopher's Stone"by Joseph Wright, 1771 / Right: Anagrammatic figure representing the vitriol, according to the alchemist motto"Visit interiora terrae; Rectificando invenies occultum lapidem"("Visit the interior parts of the earth, rectifying you will find the hidden stone"). Stolzius von Stolzembuirg, Theatrum Chymicum, 1614

In Hellenistic alchemical works already mentioned the metallurgical uses of the vitriolic substances. By vitriol a group of vitreous minerals from which sulfuric acid can be obtained is known.

Formula

• Formula : H ₂ SW ₄
• Cas Number : 7664-93-9

2D structure

Sulfuric acid

3D structure

Sulfuric acid / Molecular model of balls and rods Sulfuric acid / Molecular model of spheres

characteristics

Physical and chemical properties

Sulfuric acid belongs to the reactive group of strong oxidizing acids.

Reactions with air and water

• The reaction with water is negligible unless the acidity is above 80-90%, so the heat of the hydrolysis is extreme, it can cause serious burns.

Inflammability

• Strong oxidizing acids are generally non-flammable. They can accelerate the combustion of other materials by providing oxygen to the combustion site.
• However, sulfuric acid is highly reactive and capable of igniting finely divided combustible materials upon contact with them.
• When heated, it emits highly toxic fumes.
• Sulfuric acid is explosive or incompatible with a huge variety of substances.
• It can undergo violent chemical changes at high temperatures and pressure.
• May react violently with water.

Reactivity

• Sulfuric acid is strongly acidic.
• Reacts violently with bromine pentafluoride.
• Exploit with para-nitrotoluene at 80 ° C.
• An explosion occurs when the concentrated sulfuric acid is mixed with crystalline potassium permanganate in a container containing moisture. Manganese hepthoxide forms, which explodes at 70 ° C.
• The mixture of acrylonitrile with concentrated sulfuric acid must be kept well cooled, otherwise a vigorous exothermic reaction occurs.
• The temperature and pressure are increased by mixing in a closed container sulfuric acid (96%) in equal portions with any of the following substances: acetonitrile, acrolein, 2-aminoethanol, ammonium hydroxide (28%), aniline, n- Butyraldehyde, acid chlorosulfonic acid, ethylene diamine, ethyleneimine, epichlorohydrin, ethylene cyanohydrin, hydrochloric acid (36%), hydrofluoric acid (48.7%), propiolactone, propylene oxide, sodium hydroxide, styrene monomer.
• Sulfuric acid (concentrate) is extremely dangerous in contact with carbides, bromates, chlorates, fulminants, picrates, and powder metals.
• Sulfuric acid can induce violent polymerization of allyl chloride.
• Sulfuric acid reacts exothermically with sodium hypochlorite to produce chlorine gas.
• Mixing chlorosulfuric acid and 98% sulfuric acid gives HCl.

Toxicity

• Sulfuric acid is corrosive to all body tissues. Inhalation of vapor can cause severe lung damage. Contact with eyes can result in total loss of vision. Contact with skin may cause severe necrosis.
• Ingestion of sulfuric acid, in an amount between 1 teaspoon and a half ounce of the concentrated chemical, can be fatal for an adult. Even a few drops can be fatal if the acid gets access to the trachea.
• Chronic exposure may cause tracheobronchitis, stomatitis, conjunctivitis and gastritis. Gastric perforation and peritonitis may occur and may be followed by circulatory collapse. Circulatory shock is often the immediate cause of death.
• Those with chronic respiratory, gastrointestinal or nerve diseases and any ocular and cutaneous disease are at increased risk.

Applications

• Sulfuric acid is one of the most widely used industrial chemicals in the world. But, most of its uses can be considered as indirect, participating as a reagent instead of as an ingredient
• Most sulfuric acid ends up as spent acid in the production of other compounds, or as some kind of sulfate residue.
• A number of products incorporate sulfur or sulfuric acid, but almost all of them are special low volume products.
• About 19% of the sulfuric acid produced in 2014 was consumed in about twenty chemical processes, and the rest was consumed in a wide variety of industrial and technical applications.
• The growth in demand for sulfuric acid at the global level is due, in descending order, to the production of: phosphoric acid, titanium dioxide, hydrofluoric acid, ammonium sulfate and uranium processing and metallurgical applications.

Indirect uses of sulfuric acid

• The largest consumer of sulfuric acid is by far the fertilizer industry. It accounted for just over 58% of total world consumption by 2014. However, this share is expected to decline to about 56% by 2019, primarily as a result of higher growth in other chemical and industrial applications.
• The production of phosphate fertilizers, especially phosphoric acid, is the main market for sulfuric acid. Phosphoric acid, in turn, is used for the manufacture of fertilizer materials such as triple superphosphate and mono and diamonic phosphates. Minor amounts are used for the production of superphosphate and ammonium sulfate.
• In other industry applications, substantial amounts of sulfuric acid are used as a means of acid dehydration reaction, in organic chemistry and petrochemical processes involving reactions such as nitration, condensation and dehydration, as well as in petroleum refining , Where it is used in the refining, alkylation, and purification of crude distillates.
• In the inorganic chemical industry the use of sulfuric acid in the production of pigments of TiO2, hydrochloric acid and hydrofluoric acid is remarkable.
• In the metal processing industry, sulfuric acid is used for the pickling of steel, the leaching of copper, uranium, and vanadium minerals in the hydrometallurgical processing of minerals, and in the preparation of electrolytic baths for the purification and plating of metals Not ferrous.
• Certain processes of the manufacture of wood pulp in the paper industry, in the production of some textiles, in the manufacture of chemical fibers and in the tanning of hides, also require sulfuric acid.

Direct Uses of Sulfuric Acid

• Probably the largest use of sulfuric acid in which sulfur is incorporated into the final product is in the process of organic sulfonation, in particular for the production of detergents.
• Sulfonation also plays an important role in obtaining other organic chemicals and smaller pharmaceuticals.
• Lead-acid batteries are one of the most well-known sulfuric acid-containing consumer products and represent only a small fraction of the total consumption of sulfuric acid.
• Under certain conditions, sulfuric acid is used directly in agriculture for the rehabilitation of very alkaline soils, such as those found in the desert regions of the western United States. However, this use is not very important in terms of the total volume of sulfuric acid used.

The development of the sulfuric acid industry

Vitriol process

Copper (II) sulfate crystals forming blue vitriol

The oldest method to obtain sulfuric acid is the so-called"vitriol process", which is based on the thermal decomposition of vitriols, which are naturally occurring sulfates of various types.

The Persian alchemists, Jābir ibn Hayyān (also known as Geber, 721 - 815 AD), Razi (865 - 925 AD) and Jamal Din al - Watwat (1318 AD) included vitriol in their mineral classification lists.

The first mention of the"process of vitriol"appears in the writings of Jabir ibn Hayyan. Then the alchemists St. Albert the Great and Basilius Valentinus described the process in more detail. Alum and calcantita (blue vitriol) were used as raw materials.

At the end of the Middle Ages, sulfuric acid was obtained in small quantities in glass containers, in which sulfur was burned with saltpeter in a humid environment.

The vitriol process was used on an industrial scale from the 16th century due to an increased demand for sulfuric acid.

The focus of production was centered on the German city of Nordhausen (hence the name of the vitriol as"Nordhausen vitriol"), where iron (II) sulfate was used (green vitriol, FeSO ₄ - 7H ₂ O) as raw material, which was heated, and the resulting sulfur trioxide was mixed with water to obtain sulfuric acid (vitriol oil). The process was carried out in galleys, some of which had several levels, in parallel, in order to obtain larger amounts of vitriol oil.

Galley used in the production of vitriol

In the eighteenth century a more economical process was developed for the production of sulfuric acid known as the"process of lead chambers". Until then the maximum acid concentration obtained was 78%, whereas with the"vitriol process"concentrated acid and oleum were obtained, so that this method was continued to be used in certain sectors of industry until the appearance of the"process of Contact"in 1870, with which concentrated acid could be obtained more cheaply.

Oleum or fuming sulfuric acid (CAS: 8014-95-7), is a solution of oily consistency and dark brown color, of variable composition of sulfur trioxide and sulfuric acid, which can be described by the formula H ₂ SW ₄ .SO ₃ (Where x represents the free sulfur oxide (VI) molar content). A value for x of 1 gives the empirical formula H ₂ S ₂ OR ₇ , Which corresponds to disulphuric acid (or pyrosulphuric acid).

Lead Chamber Process

The process of the lead chamber was the industrial method used to produce sulfuric acid in large quantities, before being supplanted by the"process of contact".

In 1746 in Birmingham, England, John Roebuck began producing sulfuric acid in lead-lined chambers, which were stronger and less expensive than previously used glass containers, and could be made much larger.

Sulfur dioxide (from the combustion of elemental sulfur or sulfur-containing metal minerals such as pyrite) was introduced with steam and nitrogen oxide into large chambers lined with lead sheets. The sulfur dioxide and nitrogen dioxide were dissolved and, over a period of about 30 minutes, the sulfur dioxide was oxidized to sulfuric acid.

This allowed for the effective industrialization of sulfuric acid production and, with various refinements, this process continued to be the standard method of production for nearly two centuries.

In 1793, Clemente and Desormes achieved better results by introducing supplemental air into the lead chamber process.

In 1827, Gay-Lussac introduced a method for absorbing nitrogen oxides from the waste gases from the lead chamber.

In 1859 Glover developed a method for the recovery of nitrogen oxides from the newly formed acid by entrainment with hot gases, which made it possible to catalyze the process with nitrogen oxide continuously.

In 1923, Petersen introduced an improved tower process that allowed its competitiveness with respect to the contact procedure until the 1950s.

The chamber process became so robust that in 1946 it still represented 25% of the world production of sulfuric acid.

Contact process

The process of contact is the current method of production of sulfuric acid in high concentrations, necessary in modern industrial processes. Platinum used to be the catalyst for this reaction. However, vanadium pentoxide (V2O5) is now preferred.

In 1831, in Bristol, England, Peregrine Phillips patented the oxidation of sulfur dioxide to sulfur trioxide using a platinum catalyst at elevated temperatures.

However, the adoption of its invention, and the intensive development of the contact process, began only after the demand for oleum for the manufacture of dye had increased since about 1872.

Next, we sought better solid catalysts, and investigated the chemistry and thermodynamics of the SO2 / SO3 equilibrium.

The contact process can be divided into five stages:

1. Combination of sulfur and dioxygen (O2) to form sulfur dioxide.
2. Purification of sulfur dioxide in a purification unit.
3. Addition of an excess of dioxygen to the sulfur dioxide in the presence of the vanadium pentoxide catalyst, at temperatures of 450 ° C and pressure of 1-2 atm.
4. The sulfur trioxide formed is added to the sulfuric acid which gives rise to oleum (disulfuric acid).
5. The oleum is then added to the water to form sulfuric acid which is highly concentrated.

Scheme of the production of sulfuric acid by the contact method using pyrite as raw material

The fundamental disadvantage of nitrogen oxide processes (during the process of the lead chamber) is that the concentration of the sulfuric acid obtained is limited to a maximum of 70 to 75%, whereas the contact process produces concentrated acid (98 %).

With the development of relatively inexpensive vanadium catalysts for the contact process, together with the increasing demand for concentrated sulfuric acid, the world production of sulfuric acid in nitrogen oxide processing plants steadily declined.

By 1980 there was practically no acid in the nitrogen oxide processing plants in Western Europe and North America.

Double contact process

The double contact double absorption process (DCDA or Double Contact Double Absorption) introduced improvements to the contact process for the production of sulfuric acid.

In 1960, Bayer applied for a patent for the so-called double catalysis process. The first plant that used this process, was launched in 1964.

By incorporating an SO absorption step ₃ Prior to the final catalytic steps, the improved contact process allowed a significant increase in SO ₂ , Reducing substantially their emissions to the atmosphere.

The gases are passed back through the final absorption column, obtaining not only a high conversion performance of SO ₂ To SO ₃ (About 99.8%), but also allowing the production of a higher concentration of sulfuric acid.

The essential difference between this process and the ordinary process of contact is in the number of stages of absorption.

Since the 1970s, major industrial countries introduced stricter regulations for environmental protection, and the double absorption process became widespread in the new plants. However, the conventional contact process continues to be used in many developing countries with less demanding environmental standards.

The major impetus for the current development of the contact process is focused on increasing the recovery and utilization of the large amount of energy produced in the process. In fact, a large modern plant of sulfuric acid can be seen not only as a chemical plant, but also as a thermal energy plant.

Raw materials used in the production of sulfuric acid

Pyrite was the dominant raw material in the production of sulfuric acid until the middle of the 20th century, when large amounts of elemental sulfur began to be recovered from the refining process of petroleum and the purification of natural gas, becoming the main material Industry premium.

Currently, sulfur dioxide is obtained by different methods, from various raw materials.

In the United States, industry has been based since the early years of the 20th century on obtaining elemental sulfur from underground deposits by the"Frasch Process".

Moderately concentrated sulfuric acid is also produced by the reconcentration and purification of large quantities of sulfuric acid obtained as a by-product of other industrial processes.

The recycling of this acid is increasingly important from the point of view of the environment, especially in the main developed countries.

The manufacture of sulfuric acid based on elemental sulfur and pyrite is, of course, relatively sensitive to market conditions, since the acid produced from these materials represents a primary product.

By contrast, when sulfuric acid is a by-product, manufactured as a means of eliminating waste from another process, the level of its production is not dictated by conditions on the sulfuric acid market but by market conditions for The primary product.

Clinical Effects

• Sulfuric acid is used in industry and in some household cleaning products, such as bath cleansers. It is also used in batteries.
• Deliberate ingestion, particularly of high concentration products, can lead to serious injury and death. These ingestion exposures are uncommon in the United States, but are common in other parts of the world.
• Sulfuric acid is a strong acid that causes tissue damage and coagulation of proteins. It is corrosive to the skin, eyes, nose, mucous membranes, respiratory tract and gastrointestinal tract, or any tissue with which it comes into contact.
• The severity of the injury is determined by the concentration and duration of the contact.
• Milder exposures (concentrations of less than 10%), only cause irritation of the skin, upper respiratory tract and gastrointestinal mucosa.
• Respiratory effects from acute inhalation exposure include: irritation of the nose and throat, cough, sneezing, reflex bronchospasm, dyspnoea, and pulmonary edema. Death can occur from sudden circulatory collapse, glottis edema and compromised airways, or acute lung injury.
• Ingestion of sulfuric acid can cause immediate epigastric pain, nausea, salivation and vomiting of mucous or hemorrhagic material with the appearance of"ground coffee". Vomiting of fresh blood is occasionally observed.
• Ingestion of concentrated sulfuric acid can lead to esophageal corrosion, necrosis, and perforation of the esophagus or stomach, especially in the pylorus. Occasionally, an injury is seen in the small intestine. Subsequent complications may include stenosis and fistula formation. Metabolic acidosis may develop after ingestion.
• Severe skin burns can occur with necrosis and scarring. These can be fatal if a sufficiently large area of ​​the body surface is affected.
• The eye is especially sensitive to corrosion injury. Irritation, tearing and conjunctivitis can develop even with low concentrations of sulfuric acid. Splashes with sulfuric acid in high concentrations cause: corneal burns, loss of vision and occasionally perforation of the balloon.
• Chronic exposure may be associated with changes in lung function, chronic bronchitis, conjunctivitis, emphysema, frequent respiratory infections, gastritis, erosion of tooth enamel, and possibly cancer of the respiratory tract.

Safety and Risks

Hazard statements of the Globally Harmonized System of Classification and Labeling of Chemicals (GHS).

The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is an internationally agreed system, created by the United Nations designed to replace the various classification and labeling standards used in different countries through the use of globally consistent criteria United Nations, 2015).

Hazard classes (and their corresponding GHS chapter), classification and labeling standards, and recommendations for sulfuric acid are as follows (European Chemicals Agency, 2017, United Nations, 2015, PubChem, 2017):

GHS Hazard Classes

H303: May be harmful if swallowed. [Warning Acute Toxicity, oral - Category 5] (PubChem, 2017).

H314: Causes severe skin burns and eye damage. [Danger Skin corrosion / irritation - Category 1A, B, C] (PubChem, 2017).

H318: Causes serious eye damage [Danger Serious eye damage / eye irritation - Category 1] (PubChem, 2017).

H330: Fatal by inhalation [Hazard Acute Toxicity, Inhalation - Category 1, 2] (PubChem, 2017).

H370: Causes damage to organs [Hazard Specific target organ toxicity, single exposure - Category 1] (PubChem, 2017).

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure - Category 1] (PubChem, 2017).

H402: Harmful to aquatic life [Hazardous to the aquatic environment, acute hazard - Category 3] (PubChem, 2017).

Codes of prudence advice

P330, P321, P360, P321, P360, P321, P301, P321, P301, P301, P363, P403 + P233, P405, and P501 (PubChem, 2017).

References

1. Arribas, H. (2012) Scheme of the production of sulfuric acid by the method of contact using pyrite as raw material [image] Retrieved from wikipedia.org.
2. Chemical Economics Handbook, (2017). Sulfuric Acid. Retrieved from ihs.com.
3. Chemical Economics Handbook, (2017.) World consumption of sulfuric acid - 2013 [image]. Retrieved from ihs.com.
4. ChemIDplus, (2017). 3D structure of 7664-93-9 - Sulfuric acid [image] Retrieved from: chem.nlm.nih.gov.
5. Codici Ashburnhamiani (1166). Portrait of"Geber"of the fifteenth century. Medicea Laurenziana Library [image]. Retrieved from wikipedia.org.
6. European Chemicals Agency (ECHA), (2017). Summary of Classification and Labeling. Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation).
7. Hazardous Substances Data Bank (HSDB). TOXNET. (2017). Sulfuric acid. Bethesda, MD, US: National Library of Medicine. Retrieved from: toxnet.nlm.nih.gov.
8. Leyo (2007) Skeletal formula of sulfuric acid [image]. Retrieved from: commons.wikimedia.org.
9. Liebig's Extract of Meat Company (1929) Albertus Magnus, Chimistes Celebres [image]. Retrieved from: wikipedia.org.
10. Müller, H. (2000). Sulfuric Acid and Sulfur Trioxide. In Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH Verlag GmbH & Co. KGaA. Available at: doi.org.
11. United Nations (2015). Globally Harmonized System of Classification and Labeling of Chemicals (SGA) Sixth Revised Edition. New York, USA: United Nations publication. Retrieved from: unece.org.
12. National Center for Biotechnology Information. PubChem Compound Database, (2017). Sulfuric acid - PubChem Structure. [Image] Bethesda, MD, US: National Library of Medicine. Retrieved from: pubchem.ncbi.nlm.nih.gov.
13. National Center for Biotechnology Information. PubChem Compound Database, (2017). Sulfuric acid. Bethesda, MD, US: National Library of Medicine. Retrieved from: pubchem.ncbi.nlm.nih.gov.
14. National Oceanic and Atmospheric Administration (NOAA). CAMEO Chemicals. (2017). Chemical Datasheet. Sulfuric acid, spent. Silver Spring, MD. EU; Retrieved from: cameochemicals.noaa.gov.
15. National Oceanic and Atmospheric Administration (NOAA). CAMEO Chemicals. (2017). Chemical Datasheet. Sulfuric acid. Silver Spring, MD. EU; Retrieved from: cameochemicals.noaa.gov.
16. National Oceanic and Atmospheric Administration (NOAA). CAMEO Chemicals. (2017). Reactive Group Datasheet. Acids, Strong Oxidizing. Silver Spring, MD. EU; Retrieved from: cameochemicals.noaa.gov.
17. Oelen, W. (2011) Sulfuric acid 96 percent extra pure [image]. Retrieved from: wikipedia.org.
18. Oppenheim, R. (1890). Schwefelsäurefabrik nach dem Bleikammerverfahren in der zweiten Hälfte des 19. Lehrbuch der Technischen Chemie [image]. Retrieved from: wikipedia.org.
19. Priesner, C. (1982) Johann Christian Bernhardt und die Vitriolsäure, in: Chemie in unserer Zeit. [image]. Retrieved from: wikipedia.org.
20. Stephanb (2006) Copper sulfate [image]. Retrieved from: wikipedia.org.
21. Stolz, D. (1614) Alchemical diagram. Theatrum Chymicum [image] Retrieved from: wikipedia.org.
22. Wikipedia, (2017). Sulfuric acid. Retrieved from: wikipedia.org.
23. Wikipedia, (2017). Sulfuric acid. Retrieved from: wikipedia.org.
24. Wikipedia, (2017). Bleikammerverfahren. Retrieved from: wikipedia.org.
25. Wikipedia, (2017). Contact process. Retrieved from: wikipedia.org.
26. Wikipedia, (2017). Lead chamber process. Retrieved from: wikipedia.org.
27. Wikipedia, (2017). Oleum. Retrieved from: https://en.wikipedia.org/wiki/Oleum
28. Wikipedia, (2017). Óleum. Retrieved from: https://es.wikipedia.org/wiki/%C3%93leum
29. Wikipedia, (2017). Sulfur oxide. Retrieved from: wikipedia.org.
30. Wikipedia, (2017). Vitriol process. Retrieved from: wikipedia.org.
31. Wikipedia, (2017). Sulfur dioxide. Retrieved from: wikipedia.org.
32. Wikipedia, (2017). Sulfur trioxide. Retrieved from: wikipedia.org.
33. Wikipedia, (2017). Sulfuric acid. Retrieved from: wikipedia.org.
34. Wikipedia, (2017). Vitriolverfahren. Retrieved from: wikipedia.org.
35. Wright, J. (1770) The Alchymist, In Search of the Philosopher's Stone, Phosphorus Discovers, and prays for the successful Conclusion of his operation, was the custom of the Ancient Chymical Astrologers. [Image] Retrieved from: wikipedia.org.