每周分子 | Molecule of the Week
每周分子 | Molecule of the Week
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每周分子： 二氧化硫
Molecule of the Week:
Sulfur dioxide
二氧化硫（SO 2 ）是一种有刺激性气味的有毒气体，是单质硫燃烧的主要产物。二氧化硫在自然界中广泛存在，主要来自火山活动和化石燃料的燃烧。太阳系的其他星球中也分布有二氧化硫。在金星和木卫一（Io）的大气层中，二氧化硫是一种气体，而在其他伽利略卫星中，二氧化硫以冰的形式存在 。
二氧化硫的主要用途是制备世界上产量最大的化学品：硫酸（H 2 SO 4 ）。单质硫与氧气反应生成二氧化硫，被过量氧气进一步催化氧化可生成三氧化硫（SO 3 ）。三氧化硫与硫酸（H 2 SO 4 ）混合可生成发烟硫酸，加入水大量放热后，发烟硫酸即生成浓硫酸。这就是著名的接触法工艺，可追溯到1831年英国发明家Peregrine Phillips申请的专利 。
二氧化硫在化学实验室中有很多用途，比如用作还原剂，磺酰化反应试剂以及低温溶剂。二氧化硫还可用于保存葡萄干和西梅干等果干，还能防止葡萄酒变质 。
从危险信息表可以看出，二氧化硫是具有强烈刺激性气味的物质；但除了作为化学品的价值外，二氧化硫还有其他好处，即火山喷发产生的二氧化硫气体对气候变化产生有正面影响。当二氧化硫喷射到平流层时，与氧气发生光化学反应，生成硫酸气溶胶，而硫酸气溶胶随之反射太阳辐射，冷却大气层。不过大家也可以预料到，这种现象也存在负面影响，因为二氧化硫和硫酸会导致酸雨 。
二氧化硫 信息速览
CAS 登记号 |
7446-09-5 |
CAS SciFinder命名 |
Sulfur dioxide |
分子式 |
O 2 S |
摩尔质量 |
64.06 g/mol |
外观 |
无色气体 |
沸点 |
–10°C |
水溶性 |
110 g/L @ 20 °C |
二氧化硫危害信息
GHS分类：高压气体，液化气体 |
|
H280-内装高压气体；遇热可能爆炸 |
|
GHS分类：皮肤腐蚀/刺激，分类1B |
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H314-造成严重皮肤灼伤和眼损伤 |
|
GHS分类：严重眼损伤/眼刺激，分类1 |
|
H318-造成严重眼损伤 |
|
GHS分类：急性毒性，吸入，分类3 |
|
H331-吸入会中毒 |
|
【 关于每周分子 】
自2001年以来，“每周分子”已成为广受欢迎的栏目。多数分子由读者推荐。每个结构都经由科学家审查，并以3-D和平面图像的形式显示，同时附有该分子简介。可以通过美国化学文摘社 (CAS) 提供的CAS SciFinder n 中的CAS REGISTRY获取“每周分子”的更多信息。CAS REGISTRY中的每条物质信息都展示了物质的CAS登记号、索引名、通用名、商品名、书目信息等其他更多信息。 发送邮件至motw@acs.org推荐您感兴趣的分子吧 。
Sulfur dioxide (SO 2 ) is a pungent, toxic gas that is the primary product of burning elemental sulfur. It exists widely in nature, mostly from volcanic activity and burning fossil fuels. It is found elsewhere in the solar system, as a gas in the atmospheres of Venus and Jupiter’s moon Io and as an ice on the other Galilean moons.
The major use of SO 2 is in the manufacture of sulfuric acid (H 2 SO 4 ), the most-produced chemical worldwide. Elemental sulfur and oxygen react to form SO 2 , which is catalytically oxidized with additional oxygen to make sulfur trioxide (SO 3 ). The SO 3 is mixed with existing H 2 SO 4 to produce oleum (fuming sulfuric acid), which is added to water in a strongly exothermic process to make concentrated H 2 SO 4 . This is known as the contact process; it dates to an 1831 patent by British inventor Peregrine Phillips.
In chemical laboratories, it has multiple functions, including as a reducing agent, as a reagent in sulfonylation reactions, and as a low-temperature solvent. SO 2 is also used to preserve dried fruits such as raisins and prunes and to prevent spoilage in wine.
The hazard information table shows that SO 2 is pretty nasty stuff; but, in addition to its value as a chemical, it has another positive side: Volcanoes that emit the gas can have a beneficial effect on climate change. When SO 2 spews into the stratosphere, it reacts photochemically with oxygen to form H 2 SO 4 aerosols, which in turn reflect solar radiation and cool the atmosphere. But, as might be expected, even this has a downside because SO 2 and H 2 SO 4 contribute to acid rain.
Sulfur dioxide fast facts
CAS Reg. No. |
7446-09-5 |
|
SciFinder nomenclature |
Sulfur dioxide |
|
Empirical formula |
O 2 S |
Molar mass |
64.06 g/mol |
Appearance |
Colorless gas |
Boiling point |
–10 °C |
Water solubility |
110 g/L @ 20 °C |
Sulfur dioxide hazard information
Gases under pressure, liquefied gas |
|
H280-Contains gas under pressure; may explode if heated |
|
Skin corrosion/irritation, category 1B |
|
H314-Causes severe skin burns and eye damage |
|
Serious eye damage/eye irritation, category 1 |
|
H318-Causes serious eye damage |
|
Acute toxicity, inhalation, category 3 |
|
H331-Toxic if inhaled |
|
About Molecule of the Week
MOTW has been a popular feature on ACS website since 2001. Many molecules are suggested by our website visitors. Every structure is reviewed by a scientist and displayed in 3-D and flat images with a brief description. Each week’s molecule also links to a sample record from the CAS REGISTRY, which is searched using CAS SciFinder n . Each record displays the registry number, index name and synonyms, bibliographic information, and more. Send us a molecule suggestion at motw@acs.org .
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