Concentrated H2so4 is a Dehydrating Agent If After Step 3 You Continued by Adding H2so4 to Wells

Special Hand Disorders

Frederick M. Azar MD , in Campbell's Operative Orthopaedics , 2021

Chemical Burns

Chemical burns to the hand usually result from spills, splashing, or immersion. Most chemical burns to the hand are superficial, requiring only first aid management, and the prognosis is good. It is important to remember, however, that certain chemicals carry a risk of systemic toxicity and even death. Circumferential burns of the hand are unusual. Sulfuric acid and alkali account for most chemical injuries. Acid burns usually progress until damaged tissue neutralizes the acid or the acid is neutralized by lavage or a neutralization treatment. Injury caused by alkaline substances may progress for long periods, resulting in extensive and deep liquefaction necrosis. Jelenko and Reilly and Garner reviewed the chemicals that burn and their recommended emergency treatment ( Fig. 70.10). Prolonged water lavage is best for most chemical burns, avoiding attempts to neutralize with either alkaline or acidic solutions. It should be started at the scene ofinjury and should last 20 to 30 minutes to bring the skin pH to near neutral. Lavage for longer periods of time may be necessary for severe acid burns and for alkali burns. Chemical injury from some agents requires specific management (Table 70.1). Exposure of elemental lithium, potassium, and sodium to water causes ignition. Initial management includes mineral oil application, followed by water irrigation of particles remaining in the skin. Hydrofluoric acid, which is used in glass etching and petrochemical refining, results in continuing tissue damage because of the fluoride ion, which combines with calcium and magnesium in the tissues. Hypocalcemia may result if it involves more than 2.5% total body surface area. After initial water irrigation, application of a 2.5% calcium gluconate gel may be sufficient. If pain is not relieved promptly, injection of 10% calcium gluconate or magnesium sulfate deep to the lesions may be beneficial. For persistent pain, 10 cc of 10% calcium gluconate in 40 cc saline can be delivered as Bier block or intraarterially over 4 hours or until the pain is eliminated. Because phenol is not water soluble, removal with glycerol or polyethylene glycol has been recommended. White phosphorus particles may continue to smoke as long as they are exposed to air. Initial irrigation with a solution of 1% to 3% copper sulfate blackens the phosphorus particles so that they can be removed under water in a water bath. If the phosphorus is not irrigated first with copper sulfate, it may ignite on contact with water. Tar burns are best treated with an emulsifying agent such as Neosporin cream. Significant chemical burns seen late may require hospitalization and monitoring of the hand and digital circulation with Doppler probes and digital oximetry. If circulatory compromise results from a circumferential burn, decompression is indicated. Deeper chemical burns may require debridement and closure with skin grafts, pedicle flaps, or free tissue transfer. Recovery usually is prompt if surgical treatment is combined with a hand therapy rehabilitation program.

Sulfuric Acid

A. Saeid , K. Chojnacka , in Encyclopedia of Toxicology (Third Edition), 2014

Reactivity

Sulfuric acid is very reactive and dissolves most metals, it is a concentrated acid that oxidizes, dehydrates, or sulfonates most organic compounds, often causes charring.

Sulfuric acid reacts violently with alcohol and water to release heat. It reacts with most metals, particularly when diluted with water, to form flammable hydrogen gas, which may create an explosion hazard. Sulfuric acid is not combustible, but it is a strong oxidizer that enhances the combustion of other substances, does not burn itself. During fire, poisonous gases are emitted. Hazardous decomposition products are as follows: sulfur dioxide, sulfur trioxide, and sulfuric acid fumes.

Note: Use great caution in mixing with water due to heat release that causes explosions. Always add the acid to water, never the reverse.

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Burns

Courtney M. Townsend JR., MD , in Sabiston Textbook of Surgery , 2022

Chemical Burns

Most chemical burns are incidental from mishandling of household cleaners, although some of the most dramatic presentations involve industrial exposures. Thermal burns are, in general, short-term exposures to heat, but chemical injuries may be of longer duration, even for hours in the absence of appropriate treatment. The degree of tissue damage, as well as the level of toxicity, is determined by the chemical nature of the agent, concentration of the agent, and the duration of skin contact. Chemicals cause their injury by protein destruction, with denaturation, oxidation, formation of protein esters, or desiccation of the tissue. In the United States, the composition of most household and industrial chemicals can be obtained from the Poison Control Center in the area, which can give suggestions for treatment.

Speed is essential in the management of chemical burns. For all chemicals, lavage with copious quantities of clean water should be done immediately after removing all clothing. Dry powders should be brushed from the affected areas before irrigation. Early irrigation dilutes the chemical, which is already in contact with the skin, and timeliness increases effectiveness of irrigation; several liters of irrigant may be used. For example, 10 mL of 98% sulfuric acid dissolved in 12 L of water decreases the pH to 5.0, a range that can still cause injury. If the chemical composition is known (acid or base), monitoring of the spent lavage solution pH gives a good indication of lavage effectiveness and completion. A reasonable rule of thumb is to lavage with 15 to 20 L of tap water or more for significant chemical injuries. The lavage site should be kept drained in order to remove the earlier, more concentrated effluent. Care should be taken to drain away from uninjured areas to avoid further exposure ( Fig. 20.8).

All patients must be monitored according to the severity of their injuries. They may have metabolic disturbances, usually from pH abnormalities, because of exposure to strong acids or caustics. If respiratory difficulty is apparent, oxygen therapy and mechanical ventilation must be instituted. Resuscitation should be guided by the body surface area involved (burn formulas); however, the total fluids given may be dramatically different from the calculated volumes. Some of these injuries may be more superficial than they appear, particularly in the case of acids because of coagulative necrosis, and therefore have less resuscitation volume. Injuries from bases, however, may penetrate beyond that which is apparent on examination (liquefactive necrosis), and therefore, more volume might be indicated. For this reason, patients with chemical injuries should be observed closely for signs of adequate perfusion, such as urine output. All patients with significant chemical injuries should be monitored with indwelling bladder catheters to accurately measure outputs.

Operative excision if indicated by clinical assessment of wound depth should take place as soon as the patient is stable and resuscitated. Following adequate lavage and excision, burn wounds are covered with antimicrobial agents or skin substitutes. Once the wounds have stabilized with the indicated treatment, they are taken care of as with any loss of soft tissue. Skin grafting or flap coverage is performed as needed.

CHEMICAL FINGERPRINTING METHODS

Gregory S. Douglas , ... Kevin J. McCarthy , in Introduction to Environmental Forensics (Second Edition), 2007

9.6.2.2.4 Sulfuric Acid (EPA Method 3665A)

The sulfuric acid cleanup removes complex hydrocarbons and reactive pesticides that cause baseline rise and excessively complex chromatograms, respectively. The sample extract is exchanged to hexane and shaken vigorously or vortexed with a 1 : 1 mixture of sulfuric acid and reagent water for one minute. Transfer the hexane extract on top to a clean vial. Add 1 mL of clean hexane and repeat the mixing procedure to assure a quantitative transfer. Concentrate the extract by N-Evap. The procedure is repeated if the extract retains a brown color after it is allowed to settle.

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Contact Dermatitis and Drug Eruptions

William D. James MD , in Andrews' Diseases of the Skin , 2020

Acids

The powerful acids are corrosive, whereas the weaker acids are astringent. Hydrochloric acid produces burns that are less deep and more liable to form blisters than injuries from sulfuric and nitric acids (Fig. 6.2 ). Hydrochloric acid burns are encountered in those who handle or transport the product and in plumbers and those who work in galvanizing or tin-plate factories. Sulfuric acid produces a brownish charring of the skin, beneath which is an ulceration that heals slowly. Sulfuric acid is used more widely than any other acid in industry; it is handled principally by brass and iron workers and by those who work with copper or bronze. Nitric acid is a powerful oxidizing substance that causes deep burns; the tissue is stained yellow. Such injuries are observed in those who manufacture or handle the acid or use it in the making of explosives in laboratories. At times, nitric acid or formic acid is used in assaults secondary to interpersonal conflicts, resulting in scarring most prominently of the face, with the complication of renal failure present in a small number of cases.

Hydrofluoric acid is used widely in rust remover, in the semiconductor industry, and in germicides, dyes, plastics, and glass etching. It may act insidiously at first, starting with erythema and ending with vesiculation, ulceration, and finally necrosis of the tissue. Hydrofluoric acid is one of the strongest inorganic acids, capable of dissolving glass. Hypocalcemia, hypomagnesemia, hyperkalemia, and cardiac dysrhythmias may complicate hydrofluoric acid burns. Fluorine is best neutralized with hexafluorine solution, followed by 10% calcium gluconate solution or magnesium oxide.

Oxalic acid may produce paresthesia of the fingertips, with cyanosis and gangrene. The nails become discolored yellow. Oxalic acid is best neutralized with limewater or milk of magnesia to produce precipitation. Titanium hydrochloride is used in the manufacture of pigments. Application of water to the exposed part will produce severe burns. Therefore treatment consists only of wiping away the noxious substance.

Phenol (carbolic acid) is a protoplasmic poison that produces a white eschar on the surface of the skin. It can penetrate deep into the tissue. If a large surface of the skin is treated with phenol for cosmetic peeling effects, the absorbed phenol may produce glomerulonephritis and arrhythmias. Locally, temporary anesthesia may also occur. Phenol is readily neutralized with 65% ethyl or isopropyl alcohol.

Chromic acid burns, which may be seen in electroplating and dye production occupations, may result in extensive tissue necrosis and acute renal damage. Excision of affected skin down to the fascia should be accomplished rapidly, and hemodialysis to remove circulating chromium should start in the first 24 hours. Other strong acids that are irritants include acetic, trichloracetic, arsenious, chlorosulfonic, fluoroboric, hydriodic, hydrobromic, iodic, perchloric, phosphoric, salicylic, silicofluoric, sulfonic, sulfurous, tannic, and tungstic acids.

Polymers for a Sustainable Environment and Green Energy

T. Heinze , T. Liebert , in Polymer Science: A Comprehensive Reference, 2012

10.05.6.2.1 Sulfuric acid half esters

Sulfuric acid half ester moieties are introduced into cellulose to render the water-insoluble biopolymer soluble. Cellulose sulfates are bioactive; for example, they possess anticlotting behavior and may form PECs. ⁴³⁰ Several homogeneous and heterogeneous synthesis paths have been developed for the preparation. Sulfation of the polysaccharide with concentrated, slightly diluted H₂SO₄ or H₂SO₄ in combination with low-molecular-weight alcohols yields to degraded products. Chlorosulfonic acid and sulfur trioxide are powerful sulfating agents, but both react violently with water. More convenient is the application of the complexes of ClSO₃H and SO₃ with organic bases (e.g., TEA and Py) or dipolar aprotic solvents (e.g., DMF). Many of the sulfating reagents are highly reactive and, hence, the substituents are not uniformly distributed along the polymer chain. This may render the products water insoluble, even at high DS. The sulfation of dissolved cellulose can yield a uniform functionalization pattern. Although N₂O₄/DMF is a hazardous cellulose solvent, it is very useful for the preparation of cellulose sulfuric acid half esters. The intermediately formed nitrite is attacked by various reagents (SO₃, ClSO₃H, SO₂Cl₂, and H₂NSO₃H), leading to cellulose sulfuric acid half esters via transesterification ^129,431 with adjustable regioselectivity ( Table 17 ). The residual nitrite moieties are cleaved during the workup procedure under protic conditions.

Table 17. Regioselectivity of the sulfation of cellulose nitrite with different reagents (2   mol/mol AGU) depending on the reaction conditions. The DS values were determined by means of NMR spectroscopy

			Reaction product
Reaction conditions				Partial DS
Reagent	Time (h)	Temp. (°C)	DS	O2	O3	O6
NOSO4H	4	20	0.35	0.04	0	0.31
NH2SO3H	3	20	0.40	0.10	0	0.30
SO2Cl2	2	20	1.00	0.30	0	0.70
SO3	3	20	0.92	0.26	0	0.66
SO3	1.5	–20	0.55	0.45	0	0.10

Adapted from Wagenknecht, W.; Nehls, I.; Philipp, B. Carbohydr. Res. 1993, 240, 245, ¹²⁹ with permission.

In order to circumvent the toxic N₂O₄/DMF solvent, cellulose derivatives with activating substituents are useful starting derivatives such as TMSC, which is soluble in various solvents, for example, DMF and THF, and readily reacts with SO₃–Py or SO₃–DMF. ⁴³² Subsequent treatment with aqueous NaOH leads to a cleavage of the TMS group under formation of the sodium cellulose sulfuric acid half ester ( Figure 72 ).

Figure 72. Preparation of cellulose sulfate via TMSC.

Cellulose sulfuric acid half esters of low DS are used for the preparation of PEC (or symplex) capsules. In the case of cellulose sulfate, a DS as low as 0.2 is sufficient to impart water solubility if the substituents are uniformly distributed along the polymer chain. This can be realized by sulfation of a commercially available CA with DS 2.5 dissolved in DMF. ¹³⁶ The acetyl groups act as protecting group and the sulfation with SO₃–Py, SO₃–DMF, or acetylsulfuric acid proceeds exclusively at the unmodified hydroxyl functions ( Figure 73 ). The cellulose sulfuric acid half ester acetate formed is neutralized with sodium acetate and subsequently treated with NaOH in ethanol to cleave the acetate moieties.

Figure 73. Preparation of cellulose sulfate starting from CA, acetyl moieties acting as protective groups.

Recently, it was shown that ILs are a very promising medium for the homogeneous sulfation of cellulose. Sulfates with low DS and very good water solubility suitable for the formation of PEC can be obtained. The PECs formed with PDADMAC possess defined cutoff value for immobilization of biological matter, for example, yeast. ^433–435 They are applied in an in situ chemotherapy strategy with genetically modified cells in an immunoprotected environment and may prove useful for solid tumor therapy. ^436,437 Interestingly, very stable PEC capsules were prepared directly from the reaction mixture in the case of ILs ( Figure 74 ). Even direct encapsulation of enzymes such as glucose oxidase (GOD) was possible. ⁴³⁸

Figure 74. Polyelectrolyte complex capsules prepared from polydiallyldimethylammonium chloride and cellulose sulfate (a) and SEM image of a dried slice from the middle of one capsule (b).

Reproduced from Gericke, M.; Liebert, T.; Heinze, T. J. Am. Chem. Soc. 2009, 131, 13220, ⁴³⁸ with permission.

Cellulose sulfate shows biological activity such as anticoagulant properties, influence on the blood pressure, activity in the treatment of periodontitis, and anti-AIDS virus activity. ^439–442 The anticoagulant activity is in the focus of interest because it may lead to substances that can be an alternative to heparin. It was suggested that the anticoagulant activities of these compounds are at least partially mediated through antithrombin III. ⁴³⁹ The anticoagulant activity is influenced by the pattern of functionalization. For the cellulose ester, it is observed that the sulfation of the secondary OH groups is a predominant factor for the anticoagulant activity and the molecular mass is only of minor importance. In contrast, the toxicity is influenced by both the substituent distribution and the molecular mass. ⁴⁴³

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Mercury Production

F. Habashi , in Encyclopedia of Materials: Science and Technology, 2001

(b) Precipitation–filtration methods

These methods are suitable for the removal of large amounts of mercury in the gas stream (800   mgm⁻³). They are based on the formation of an insoluble mercury compound, which can be removed as a slurry in scrubbers. The slurry can then be filtered to recover the mercury compound and recycle the solution (Fig. 1).

Figure 1. Recovery of mercury as a by-product from smelter gases by precipitation and filtration.

Sulfuric acid method. In this method the gas is cooled in waste heat boilers and its dust content is removed in cyclones and electrostatic precipitators. The gas at 350 °C is cooled in heat exchangers to about 200 °C using concentrated H₂SO₄ as a heat exchange medium. It is then scrubbed with the same acid, which is now at 150–200 °C, to convert elemental mercury into a sulfate according to:

$2\text{Hg}+{\text{H}}_2{\text{SO}}_4+\frac{1}{2}{\text{O}}_2\to {\text{Hg}}_2{\text{SO}}_4+{\text{H}}_2\text{O}$

The acid is recycled to become saturated in Hg₂SO₄. As a result, crystals of Hg₂SO₄ precipitate and can be separated in thickeners. Since the smelter gases contain moisture, which would dilute the acid and render it ineffective as a sulfating agent, an optimum temperature of 150–200 °C and acid concentration of 85–90% H₂SO₄ must be used.

Selenium scrubbers. This process is based on the fact that if a certain level of amorphous elemental selenium is maintained in the circulating wash liquid in the gas scrubbing circuit, mercury is effectively removed from the gas as mercury selenide, HgSe.

Mercuric chloride method. This is the most widely used method and is based on the oxidation of mercury vapor by mercuric chloride solution at 30–40 °C and its precipitation as mercurous chloride according to:

${\text{HgCl}}_2+\text{Hg}\to {\text{Hg}}_2{\text{Cl}}_2$

Hydrogen sulfide method. In this process HgS is precipitated from the gas stream by injecting a controlled amount of hydrogen sulfide, whereby the following reactions take place:

$\begin{array}{c}2{\text{H}}_2\text{S}+{\text{SO}}_2\to 3\text{S}+2{\text{H}}_2\text{O}\\ \text{S}+\text{Hg}\to \text{HgS}\end{array}$

Mercury sulfide is then removed in the gas filtration system.

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Cellular Energy Allocation

François Gagné , in Biochemical Ecotoxicology, 2014

8.1.2.1 Reagents

Concentrated sulfuric acid : H₂SO₄, keep in fume hood and wear safety glasses, gloves, and lab coat.

Phospho-vanillin reagent: First dissolve 0.06   g vanillin in 10   mL SQ water. Take 3.5   mL and carefully transfer to 60   mL phosphoric acid (under fume hood and wearing protective gear) and 5   mL of water. Always pour in the direction of concentrated acid to the water to eliminate strong exothermic reactions (explosions).

Lipid standard: Prepare 23.3   µL of Triton X-100 (density of 1.07   g/mL) in 200   mL of SQ water to obtain 12.5   mg/mL. Olive or canola oil could also be prepared in ethanol, but Triton X-100 is more soluble and easy to manipulate.

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POLYCHLORINATED BIPHENYLS

J. de Boer , in Encyclopedia of Analytical Science (Second Edition), 2005

Destructive Lipid Removal

Treatment with sulfuric acid or concentrated base offers an alternative solution for the removal of lipids and other interferences. Because PCBs are generally resistant to sulfuric acid, concentrated sulfuric acid treatment is used for degradation of most aliphatic and many aromatic compounds in environmental samples. Sulfuric acid may affect other compounds such as some halogenated pesticides (e.g., dieldrin) that are determined together with PCBs in one extract.

Lipids can be saponified by heating the extract in a small volume of solvent with 20% ethanolic potassium hydroxide at ∼70°C for 30   min. Saponification is not only used for lipids but is also used for the removal of sulfur from sediment extracts. The conditions of saponification are critical. Too high temperatures and too long saponification times can cause decomposition of higher chlorinated compounds such as hexa-deca PCBs, in particular when trace metals are present, e.g., in sediment samples. Metals can act as a catalyst. The chlorine in aromatic molecules with four or more chlorine atoms at one ring can be substituted by an ethoxy group under hot saponification conditions. Therefore, care must be taken with respect to these congeners during saponification and alternative cleanup procedures without saponification must be considered. Although the percentage of degradation is normally low, the converted quantities may seriously affect the non-ortho CB concentrations as these are normally ∼100–1000-fold lower than those of the indicator CBs.

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Back-End-of-Line Cleaning

S. Raghavan , ... V. Lowalekar , in Handbook for Cleaning/Decontamination of Surfaces, 2007

3.1. Dilute Sulfuric-Peroxide Chemistries

Solutions containing sulfuric acid and hydrogen peroxide in much smaller amounts than Piranha have been found to successfully remove etch residues from the top and sidewalls of Al/TiN structures. These chemistries are known as dilute sulfuric-peroxide (DSP), or DSP+ if they contain proprietary additives such as fluoride ions. Typically, they contain 5–10% sulfuric acid, 5–10% hydrogen peroxide (as 30%) and DI water. Hydrofluoric acid, at levels of 50–200 ppm, is found in DSP+ chemistries [15–17]. These work well in the temperature range of 20–30°C, without inducing corrosion of Al. In a single-wafer spray tool, excellent removal of etch residues in less than 2 min has been documented.

The sulfuric acid in the formulation dissolves aluminum oxide contained in ashed residues. This dissolution breaks up the etch residues, resulting in their removal. The DSP formulation is a slow isotropic etchant of aluminum; sulfuric acid in the chemical system dissolves aluminum while the peroxide passivates the aluminum surface. In the presence of fluoride and peroxide, the passive layer is etched and then reformed. Rath et al. [15] investigated the effect of anodic potential on the dissolution of aluminum in DSP solutions. The etch rate of Al in DSP solutions is in the range of 5–9 nm/min and exhibits weak dependence on applied potential (Figure E.2.I.7). From this, they concluded that the steady-state etching reactions are more chemical than electrochemical in nature. Since many metal stack structures contain Al in contact with TiN, it is important that cleaning chemistry does not induce galvanic corrosion of aluminum. Even for TiN/Al area ratio of 20:1, DSP chemistry does not induce galvanic corrosion of Al. Etch rates of commonly used materials [19] in DSP chemistry is presented in Table E.2.I.6.

Figure E.2.I.7. Steady-state etch rate of Al in DSP+ chemistry [7]

Table E.2.I.6. Etch characteristics of selected device layers in DSP chemistry [11]

Device Layer	Amount of Material Removed (Å)	Etch Time (s)
TEOS	<2	120
HDP TEOS	<1.5	120
PVD Ti	<0.25	90
IMP Ti	<1.1	90
PVD TiN	<44	120
Al/Cu (0.5%)	<65	90

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