Hydroquinone
- p-Benzenediol
- Quinol
- 1,4-Dihydroxybenzene
- p-Dihydroxybenzene
Hydroquinone | |
| |
| Formula | C6H4(OH)2 |
| Structure | |
| Description | White or colorless, odorless, crystalline solid when pure. Commercial grades are typically white, off-white, light tan or light grey crystalline solids. |
| Uses | As photographic reducer & developer, as reagent in determination of small quantities of phosphate, as antioxidant. |
| Registry Numbers and Inventories. | |
| CAS | 123-31-9 |
| EC (EINECS/ELINCS) | 204-617-8 |
| EC Index Number | 604-005-00-4 |
| EC Class | Carcinogenic Category 3; Mutagenic Category 3; Harmful; Irritant; Sensitising; Dangerous for the Environment |
| EC Risk Phrase | R 22 40 41 43 50 68 |
| EC Safety Phrase | S 26 36/37/39 61 |
| RTECS | MX3500000 |
| RTECS class | Tumorigen; Mutagen; Reproductive Effector; Human Data; Primary Irritant |
| UN (DOT) | 2662 |
| Merck | 13,4833 |
| Beilstein/Gmelin | 605970 |
| Beilstein Reference | 4-06-00-05712 |
| Swiss Giftliste 1 | G-1691 |
| Canada DSL/NDSL | DSL |
| US TSCA | Listed |
| Austrailia AICS | Listed |
| New Zealand | Listed |
| Japan ENCS (MITI) | Listed |
| Korea ECL | Listed |
| Properties. | |
| Formula | C6H6O2 |
| Formula mass | 110.11 |
| Melting point, °C | 172 |
| Boiling point, °C | 285 |
| Vapor pressure, mmHg | 0.01 (60 C) |
| Vapor density (air=1) | 3.81 |
| Saturation Concentration | 0.024 ppm at 25 C (calculated) |
| Density | 1.328 g/cm3 (25 C) |
| Solubility in water | 70 g/L |
| Refractive index | 1.632 (25 C) |
| pKa/pKb | 9.96 (pKa) |
| Partition coefficient, pKow | 0.59 |
| Heat of fusion | 27.2 kJ/mol |
| Heat of vaporization | 94.13 kJ/mol |
| Heat of combustion | -2848 kJ/mol |
| Hazards and Protection. | |
| Storage | Store in a cool, dry place. Do not store in direct sunlight. |
| WHMIS | D1B D2B |
| Handling | Wash thoroughly after handling. Use only in a well ventilated area. Minimize dust generation and accumulation. Avoid contact with eyes, skin, and clothing. Avoid ingestion and inhalation. |
| Protection | Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure. |
| Respirators | Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary. |
| Small spills/leaks | Sweep up or absorb material, then place into a suitable clean, dry, closed container for disposal. Avoid generating dusty conditions. |
| Stability | Stable under normal temperatures and pressures. Substance undergoes color change upon exposure to light and air. |
| Incompatibilities | Strong oxidizers, alkalies. Undergoes violent reaction with sodium hydroxide. |
| Decomposition | Carbon monoxide, carbon dioxide, quinone. |
| Fire. | ||||
| Flash Point,°C | 165 | |||
| Autoignition, °C | 515 | |||
| Upper exp. limit, % | 15.3 | |||
| Lower exp. limit, % | 1.6 | |||
| Fire fighting | Wear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. Dusts at sufficient concentrations can form explosive mixtures with air. Extinguishing media: Use foam, dry chemical, or carbon dioxide. | |||
| Fire potential | Slightly flammable. Combustible but must be preheated for ignition. | |||
| Hazards | Dust cloud may explode if ignited in an enclosed area. It can react with oxidizing materials and is rapidly oxidized in the presence of alkaline materials. Oxidizes in air. | |||
| Combustion products | Fire may produce irritating, corrosive and/or toxic gases. | |||
| NFPA | Health | 2 | ||
| Flammability | 1 | |||
| Reactivity | 0 | |||
| Health. | |
| Exposure limit(s) | TLV: ppm; 2 mg/m3 (ACGIH 1992-1993). OSHA PEL: TWA 2 mg/m3 NIOSH REL: C 2 mg/m3 15-minute NIOSH IDLH: 50 mg/m3 |
| Poison_Class | 3 |
| Exposure effects | Prolonged or repeated skin contact may cause sensitization dermatitis and possible destruction and/or ulceration. |
| Ingestion | May cause severe irritation of the digestive tract. May be harmful if swallowed. May caues dizziness nausea, sense of suffocation, increased respiratory rate, vomitting, pallor, muscle twitching, cyanosis, delerium, collapse. May cause green or brownish green urine which continues to darken upon standing. |
| Inhalation | May cause respiratory tract irritation. Causes narcotic effects including headache, dizziness, weakness, unconsciousness, and possible death. Vapors may cause dizziness or suffocation. Inhalation of dust may cause respiratory tract irritation. Exposure to high concentration of vapor may caues irritation, photophobia, lacrimation, and corneal ulceration. |
| Skin | Causes severe skin irritation. May cause skin sensitization, an allergic reaction, which becomes evident upon re-exposure to this material. May cause dermatitis. Repeated exposure may cause hyperpigmentation of fair skin and depigmentation of dark skin. |
| Eyes | May cause eye irritation. Repeated exposure may cause corneal abnormalities including structural changes and brownish discoloration which can lead to decreased visual acuity and blindness. |
First aid |
|
| Ingestion | If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately. |
| Inhalation | Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid. |
| Skin | Get medical aid. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. |
| Eyes | Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately. Do NOT allow victim to rub or keep eyes closed. |
| Transport. | ||
| UN number | 2662 | |
| Response guide | 153 | |
| Hazard class | 6.1 | |
| Packing Group | III | |
| USCG CHRIS Code | HDQ | |
| HS Code | 2907 22 10 | |
| Std. Transport # | 4925129 | |