萘是一种有机化合物,分子式C10H8,白色,易挥发并有特殊气味的晶体.从炼焦的副产品煤焦油中大量生产,而用于合成染料、树脂等。通常的卫生球就是用萘制成的。1958年以来，代替滴滴涕等氯化产品的甲萘威投产后，用作杀虫剂原料的比例有所增加。萘的用途分配，各国有所不同，大致用于生产邻苯二甲酸酐约占70%，染料中间体（如β－萘酚）和橡胶加工助剂约占15%,杀虫剂约占6%,鞣革剂约占4%，染料生产较少的国家,如美国则用于生产杀虫剂的比例较大。

Naphthalene is an organic compound with the molecular formula C10H8. It is a white, volatile, and odorous crystal. It is produced in large quantities from coal tar, a byproduct of coking, and is used in the synthesis of dyes, resins, etc. The usual sanitary balls are made of naphthalene. Since 1958, the proportion of carbaryl used as a pesticide raw material has increased after it was put into production to replace chlorinated products such as DDT. The allocation of uses of naphthalene varies among countries, with approximately 70% being used for the production of phthalic anhydride and dye intermediates such as β－ Naphthol and rubber processing additives account for about 15%, insecticides account for about 6%, and tanning agents account for about 4%. Countries with less dye production, such as the United States, have a larger proportion of insecticides.

萘 - 理化性质

Naphthalene - Physical and Chemical Properties

物理性质

physical property

密度

density

熔点80.5℃,沸点217.9℃,凝固点,80.5℃,闪点78.89℃,折射率1.58212（100℃）恒容燃烧热：40.19KJ/g(标准大气压，298.15K） 恒压燃烧热：40205J/g(标准大气压，298.15K）。

Melting point 80.5 ℃, boiling point 217.9 ℃, freezing point 80.5 ℃, flash point 78.89 ℃, refractive index 1.58212 (100 ℃), constant volume combustion heat: 40.19KJ/g (standard atmospheric pressure, 298.15K), constant pressure combustion heat: 40205J/g (standard atmospheric pressure, 298.15K).

不溶于水，溶于乙醇和乙醚等

Insoluble in water, soluble in ethanol and ether, etc

易挥发，易升华

Easy to evaporate and sublimate

溶于乙醇后，将其滴入水中，会出现白色浑浊。

After dissolving in ethanol, dropping it into water will result in white turbidity.

温和氧化剂得醌，强烈氧化剂得酸酐。萘环比侧链更易氧化，所以不能用侧链氧化法制萘甲酸。电子云密度高的环易被氧化。

A mild oxidant yields quinone, while a strong oxidant yields anhydride. Naphthalene rings are more easily oxidized than side chains, so side chain oxidation cannot be used to produce naphthoic acid. Rings with high electron cloud density are prone to oxidation.

（2） 萘的还原

(2) Reduction of naphthalene

萘可与5个H2加成生成十氢化萘。

Naphthalene can be added with 5 H2 to form decahydronaphthalene.

（3）萘的加成

(3) Addition of naphthalene

（4）萘的亲电取代反应

(4) Electrophilic substitution reaction of naphthalene

萘的α-位比β-位更易发生亲电取代反应。α-位取代两个共振式都有完整的苯环。β-位取代只有一个共振式有完整的苯环。

Naphthalene α- Bitwise ratio β- The site is more prone to electrophilic substitution reactions. α- Both resonance formulas have a complete benzene ring. β- There is only one resonance formula with a complete benzene ring in place of a substitution.

在萘环上主要发生亲电取代，同苯环一样，但活性比苯环强

The electrophilic substitution mainly occurs on the naphthalene ring, similar to the benzene ring, but with stronger activity than the benzene ring

从中间对称的两个C旁边的C开始标，其中1，4，5，8号碳活性完全一样（称为α碳），2，3，6，7号碳性质完全一样（称为β碳）。

Start with the C next to the symmetrical two Cs in the middle, where the carbon activities of numbers 1, 4, 5, and 8 are exactly the same (referred to as α Carbon), carbon numbers 2, 3, 6, and 7 have identical properties (referred to as β Carbon).

一般情况下，α碳活性大于β碳，取代基在α位上，这是由动力学控制，温度较高时，α碳[4] 上取代基会转移到β碳上。

In general, α Carbon activity greater than β Carbon, substituent in α In terms of position, this is controlled by dynamics. When the temperature is high, α The substituents on carbon [4] will transfer to β On carbon.

但在萘的弗瑞德-克来福特酰基化反应，不加热却生成了α位和β位的混合物。如用硝基甲烷为溶剂，则主要生成β酰化产物 。

But in the Friedel-Crafterford acylation reaction of naphthalene, it was generated without heating α Bitwise sum β A mixture of bits. If nitromethane is used as a solvent, it mainly generates β Acylation products.

修改：中间的两个碳不编号。

Modification: The two carbons in the middle are not numbered.

萘 - 萘的用途

The Use of Naphthalene Naphthalene

广泛用作制备染料、树脂、溶剂等的原料，也用作驱虫剂（俗称卫生球或樟脑丸）。起取代反应比起加成反应容易。

Widely used as a raw material for preparing dyes, resins, solvents, etc., and also as a repellent (commonly known as sanitary balls or camphor balls). Substitution reactions are easier than addition reactions.

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