Diborane химические свойства, назначение, производство
Описание
Diborane is a colorless gas at room temperature
and atmospheric pressure. It has an unpleasant,
distinctive, sickly sweet odor. Diborane is a
highly flammable gas that forms a flammable
mixture with air over a range of 0.9 percent to
98 percent diborane (at 1 atm). Diborane bums
in air (or oxygen) with a blue to green flame.
Diborane is considered pyrophoric at room
temperature. The gas is easily ignited by a spark
or the heat of reaction with moisture in air.
Pure diborane is insensitive to mechanical
shock; however, shock and thermally sensitive
mixtures may be formed in the presence of impurities
such as oxygen, water, halogenated hydrocarbons,
and so on. Thermal decomposition
of diborane to hydrogen can result in excessive
pressure buildup. Vessels for containment
of diborane should be designed to contain
such resultant decomposition pressure.
Химические свойства
Diborane is a compressed, colorless, and flam-
mable gas. It has a nauseating, sickly sweet odor.
Использование
Diborane is used as a rocket propellant, in thevulcanization of rubber, as a polymerizationcatalyst, as a reducing agent, in the synthesisof trialkyl boranes, and as a doping agent(Merck 1996).
Методы производства
Diborane now can be produced more easily and in larger quantities by the reaction of LiH, NaH or alkali borohydrides with BF3 diethyl etherate, To obtain good yields, the alkali hydrides must be very finely powdered.
Реакции воздуха и воды
Highly flammable. Ignites spontaneously in moist air (forms hydrogen and boric acid), [Haz. Chem. Data (1966)]. Oxygen and Diborane form spontaneously explosive mixtures, [J. Amer. Chem. Soc. 76, 1997(1954)].
Профиль реактивности
Diborane is a colorless, air and moisture-sensitive gas, highly toxic. Diborane ignites in air. Diborane is very explosive when exposed to heat or flame, on contact with moisture Diborane produces hydrogen gas. Explosive reaction with benzene vapor, chlorine, nitric acid and tetravinyllead [Bretherick, 5th ed., 1995, p. 77]. Explosive reaction with dimethyl sulfoxide [Shriver, 1969, p. 209], violent reaction with halocarbon liquids used as fire extinguishants (e.g., carbon tetrachloride). Reaction with Al or Li produces complex hydrides that may ignite spontaneously in air [Haz. Chem. Data, 1975, p. 114].
Опасность
Diborane is pyrophoric and will ignite upon exposure to air. The boiling point is ?135°F and the flammable range is 0.8%–88% in air. The ignition temperature is 100° (37°C) to 140°F (60°C), and the flash point is 130°F (54°C). Diborane will react violently with halogenated fire-extinguishing agents, such as the halons. The four-digit UN identification number is 1911. The NFPA 704 designation is health 4, flammability 4, and reactivity 3. The white section of the diamond has a W with a slash through it, indicating water reactivity.
Угроза здоровью
Boranes are highly toxic by inhalation, skin absorption or ingestion. They may produce acute or chronic poisoning. Diborane is an irritant to the lungs and kidneys. The primary effect of Diborane poisoning is lung congestion caused by local tissue irritation produced by the exothermic reaction of hydrolysis.
Пожароопасность
Diborane will ignite spontaneously in moist air at room temperature. Also, Diborane reacts violently with vaporizing liquid-type extinguishing agents. Diborane hydrolyzes in water to hydrogen and boric acid. Incompatible with air, halogenated compounds, aluminum, lithium, active metals, oxidized surfaces, chlorine, fuming nitric acid, nitrogen trifluoride, oxygen, and phosphorus trifluoride. Avoid moist air, electrical sparks, open flames or any other heat source. Hazardous polymerization may occur.
Воспламеняемость и взрывоопасность
Diborane is a flammable gas that ignites spontaneously in moist air at room temperature and forms explosive mixtures with air from 0.8% up to 88% by volume. Diborane reacts with halogenated hydrocarbons, and fire extinguishing agents such as Halon or carbon tetrachloride are therefore not recommended. Carbon dioxide extinguishers should be used to fight diborane fires. Fires involving diborane sometimes release toxic gases such as boron oxide smoke.
Использование в материалах
Common metals are suitable as materials of
construction. These include the following metals
and metal alloys: chrome-molybdenum steel,
Type 300 stainless steel, brass, lead, Monel,
K-Monel, and nickel. Piping and appurtenances
for undiluted diborane must be designed by
experienced engineers and safety and fire protection specialists. Saran, polyethylene, Kel-F,
Teflon, graphite, and high-vacuum silicone
grease are satisfactory for use with diborane.
In addition to the ability of a material to withstand
chemical attack, the evaluation of materials
compatibility with diborane should also emphasize
the effect of the material on diborane
stability (as expressed by the decomposition
rate). The use of the following materials is not
recommended:
? Metal oxides
? Natural rubbers
? Neoprene
? Leak-lock
? Permatex
? Ordinary oil and grease
? Nordel 1145 RPT elastomer, unfilled and
Si02-filled
? silicon elastomer, unfilled and SiOrfilled
? CIS-4 polybutadiene elastomer, unfilled
and SiOrfilled
Возможный контакт
Diborane is used as the source of
boron in the semiconductor industry; as a catalyst for olefin
polymerization; a rubber vulcanizer; a reducing agent;
a flame-speed accelerator; a chemical intermediate for
other boron hydrides; as a doping agent; in rocket propel-
lants, and in the conversion of olefins to trialkyl boranes
and primary alcohols.
хранилище
diborane should be used only in a fume hood free of ignition sources and should be stored in a cold, dry, wellventilated area separated from incompatible substances and isolated from sources of sparks and open flames.
Перевозки
UN1911 Diborane, Hazard Class: 2.3; Labels:
2.3-Poisonous gas, 2.1-Flammable gas Inhalation Hazard
Zone A. Cylinders must be transported in a secure upright
position, in a well-ventilated truck. Protect cylinder and
labels from physical damage. The owner of the compressed
gas cylinder is the only entity allowed by federal law
(49CFR) to transport and refill them. It is a violation of
transportation regulations to refill compressed gas cylinders
without the express written permission of the owner.
Несовместимости
A strong reducing agent. Unstable above
8
C. The presence of contaminants may lower the autoigni-
tion temperature; ignition may take place at, or below,
room temperature. Diborane can polymerize, forming liquid
pentaborane (See P:0190). It ignites spontaneously in moist
air; and on contact with water, hydrolyzes exothermically
forming hydrogen and boric acid. Contact with halogenated
compounds (including fire extinguishers) may cause fire
and explosion. Contact with aluminum, lithium and other
active metals form hydrides which may ignite spontane-
ously. Incompatible with aluminum, carbon tetrachloride;
nitric acid; nitrogen trifluoride and many other chemicals.
Reacts with oxidized surfaces. Attacks some plastics,
rubber or coatings.
Утилизация отходов
Return refillable compressed
gas cylinders to supplier. Incineration with aqueous scrub-
bing of exhaust gases to remove B2O3 particulates.
Diborane препаратная продукция и сырье
сырьё
препарат