SULFURIC ACID

Sulfuric acid
(Oil of vitriol)
CAS 7664-93-9

H₂ SO₄

Clear, colorless, oily liquid
bp 300 to 338 °C (loses SO₃above 300 °C), mp 11 °C
Miscible with water in all proportions

Odorless

3.4 (air = 1.0)

<0.3 mmHg at 25 °C

Noncombustible

LD₅₀ oral (rat) 2140 mg/kg

LC₅₀ inhal (rat) 347 mg/m³(1 h)

PEL (OSHA) 1 mg/m ³

TLV-TWA (ACGIH) 1 mg/m ³

STEL (ACGIH) 3 mg/m ³

Highly corrosive; causes severe burns on eye and skin contact and upon inhalation of sulfuric acid mist; highly reactive, reacts violently with many organic and inorganic substances.

Concentrated sulfuric acid is a highly corrosive liquid that can cause severe, deep burns upon skin contact. The concentrated acid destroys tissue because of its dehydrating action, while dilute H₂ SO₄acts as a skin irritant because of its acid character. Eye contact with concentrated H₂ SO₄causes severe burns, which can result in permanent loss of vision; contact with dilute H₂ SO₄results in more transient effects from which recovery may be complete. Sulfuric acid mist severely irritates the eyes, respiratory tract, and skin. Because of its low vapor pressure, the principal inhalation hazard from sulfuric acid involves breathing in acid mists, which may result in irritation of the upper respiratory passages and erosion of dental surfaces. Higher inhalation exposures may lead to temporary lung irritation with difficulty breathing. Ingestion of sulfuric acid may cause severe burns to the mucous membranes of the mouth and esophagus.

Animal testing with sulfuric acid did not demonstrate carcinogenic, mutagenic, embryotoxic, or reproductive effects. Chronic exposure to sulfuric acid mist may lead to bronchitis, skin lesions, conjunctivitis, and erosion of teeth.

Sulfuric acid is noncombustible but can cause finely divided combustible substances to ignite. Sulfuric acid reacts with most metals, especially when dilute, to produce flammable and potentially explosive hydrogen gas.

Concentrated sulfuric acid is stable, but may react violently with water and with many organic compounds because of its action as a powerful dehydrating, oxidizing, and sulfonating agent. Ignition or explosions may occur on contact of sulfuric acid with many metals, carbides, chlorates, perchlorates, permanganates, bases, and reducing agents. Sulfuric acid reacts with a number of substances to generate highly toxic products. Examples include the reaction of H₂ SO₄with formic or oxalic acid (CO formation), with cyanide salts (HCN formation), and sodium bromide (SO₂ and Br₂ formation).

Sulfuric acid should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C. Splash goggles and rubber gloves should be worn when handling this acid, and containers of sulfuric acid should be stored in a well-ventilated location, separated from organic substances and other combustible materials. Containers of sulfuric acid should be stored in secondary plastic trays to avoid corrosion of metal storage shelves due to drips or spills. Water should never be added to sulfuric acid because splattering may result; always add acid to water.

In the event of skin contact, immediately wash with soap and water and remove contaminated clothing. In case of eye contact, promptly wash with copious amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain medical attention. If sulfuric acid is ingested, obtain medical attention immediately. If large amounts of sulfuric acid mist are inhaled, move the person to fresh air and seek medical attention at once.

Carefully neutralize small spills of sulfuric acid with a suitable agent such as sodium carbonate, further dilute with absorbent material, place in an appropriate container, and dispose of properly. Respiratory protection may be necessary in the event of a large spill or release in a confined area.

Excess sulfuric acid and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines.

The information in this LCSS has been compiled by a committee of the National Research Council from literature sources and Material Safety Data Sheets and is believed to be accurate as of July 1994. This summary is intended for use by trained laboratory personnel in conjunction with the NRC report Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. This LCSS presents a concise summary of safety information that should be adequate for most laboratory uses of the title substance, but in some cases it may be advisable to consult more comprehensive references. This information should not be used as a guide to the nonlaboratory use of this chemical.

Copyright 1995 National Academy of Sciences. All rights reserved.