每周分子 | Molecule of the Week

Original ACS 美国化学会 ACS美国化学会 2022-07-01

收录于合集 #每周分子 110个

每周分子：四氯化碳

Molecule of the Week: Carbon tetrachloride

一定年龄的读者应该还记得，“carbon tet”是一种家用溶剂，几乎可以从任何表面轻易地去除有机残留物，如粘合剂和油脂。它被广泛地应用在干洗剂、制冷剂和灭火剂中。

然而，在20世纪70年代和80年代，毒理学家发现吸入或皮肤接触四氯化碳(CCl₄)会损害许多器官，包括肝脏、肾脏和中枢神经系统(见危害表)。据1995年的《蒙特利尔议定书》，CCl4也是一种“温室气体”，它消耗了地球平流层的臭氧。因此，CCl4的生产和使用已大大减少。

在鼎盛时期，人们通过氯化C1化合物(如氯仿、二硫化碳以及后期使用甲烷)生产CCl4。目前CCl4的产量很小，是生产氯仿和二氯甲烷的副产品; 然而，美国的产量仍是《蒙特利尔议定书》所要求的15倍。

目前生产的CCl4被用作臭氧安全制冷剂的原料，并在一些小型农业和工业过程中使用。在最近一份根据美国《有毒物质控制法》(Toxic Substances Control Act)对CCl4标准进行风险评估的草案中，美国环境保护署(US Environmental Protection Agency)报告称：如果工人穿戴适当的个人防护设备，在生产工厂使用CCl4是安全的。该评估预计在6月完成。

四氯化碳信息速览

CAS 登记号	56-23-5
SciFinder命名	Methane, tetrachloro-
分子式	CCl₄
摩尔质量	153.82 g/mol
外观	无色液体
沸点	77 ºC
水溶性	0.81 g/L

四氯化碳危害信息

GHS*分类：急性毒性，口服，分类3
H301-吞食有毒
GHS分类：急性毒性，皮肤，分类3
H311-皮肤接触有毒
GHS分类：皮肤过敏，分类1B
H317-可能引起皮肤过敏反应
GHS分类：急性毒性，吸入，分类3
H331-吸入有毒
GHS分类：致癌性，分类2
H351-怀疑会致癌
GHS分类：特定目标器官毒性(肝，肾)，反复接触，吸入，分类1
H372-长期吸入或反复接触会对器官(肝，肾)造成损害
GHS分类：对水生环境有害，急性危害，分类3
H402-对水生生物有害
GHS分类：对水生环境有害，长期危害，分类3
H412-对水生生物有害并具有长期影响
GHS分类：危害臭氧层，分类1
H420-破坏高空臭氧层，危害公共健康和环境

【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SciFinder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。

Readers of a certain age can remember when “carbon tet” was the go-to household solvent that easily removed organic residues such as adhesives and oils from almost any surface. It was also a widely used dry-cleaning solvent, refrigerant, and fire suppressant.

During the 1970s and ’80s, however, toxicologists discovered that inhalation of or skin contact with carbon tetrachloride (CCl4) can damage many organs, including the liver, kidneys, and central nervous system (see hazard table). CCl4 is also a “greenhouse gas” that, according to the 1995 Montreal Protocol, depletes ozone in the Earth’s stratosphere. Consequently, production and use have been significantly reduced.

In its heyday, CCl4 was produced by chlorinating C1 compounds such as chloroform, carbon disulfide, and, in later years, methane. What little is available today is a coproduct from the manufacture of chloroform and dichloromethane; however, US production is still 15 times the amount called for in the Montreal Protocol.

The CCl4 currently produced is used as a feedstock for ozone-safe refrigerants and in some minor agricultural and industrial processes. In a recent draft risk assessment of CCl4 standards under the Toxic Substances Control Act, the US Environmental Protection Agency reports that the compound is safe to use in manufacturing plants if workers wear appropriate personal protective equipment. The assessment is scheduled to be finalized by June.

Carbon tetrachloride fast facts

CAS Reg. No.	56-23-5
SciFinder nomenclature	Methane, tetrachloro-
Empirical formula	CCl₄
Molar mass	153.82 g/mol
Appearance	Colorless liquid
Boiling point	77 ºC
Water solubility	0.81 g/L

Carbon tetrachloride hazard information

Hazard class: Acute toxicity, oral, category 3
H301-Toxic if swallowed
Hazard class: Acute toxicity, dermal, category 3
H311-Toxic in contact with skin
Hazard class: Skin sensitisation, category 1B
H317-May cause an allergic skin reaction
Hazard class: Acute toxicity, inhalation, category 3
H331-Toxic if inhaled
Hazard class: Carcinogenicity, category 2
H351-Suspected of causing cancer
Hazard class: Specific target organ toxicity (liver, kidney), repeated exposure, inhalation, category 1
H372-Causes damage to organs (liver, kidney) through prolonged or repeated exposure if inhaled
Hazard class: Hazardous to the aquatic environment, acute hazard, category 3
H402-Harmful to aquatic life
Hazard class: Hazardous to the aquatic environment, long-term hazard, category 3
H412-Harmful to aquatic life with long-lasting effects
Hazard class: Hazardous to the ozone layer, category 1
H420-Harms public health and the environment by destroying ozone in the upper atmosphere

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 SciFinder. 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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