從煤焦油中分離出來的萘稱之為焦油萘，在高溫煤焦油中萘約占8-12%，從焦油精餾塔側線切取出溫度區間為210-230℃的萘油餾分經過洗滌脫酚再精餾分離輕組分，便可得到凝固點為78℃純度為96%的工業萘

The naphthalene separated from coal tar is called tar naphthalene. In high-temperature coal tar, naphthalene accounts for about 8-12%. The naphthalene oil fraction with a temperature range of 210-230 ℃ is cut from the side line of the tar distillation tower, washed, dephenolized, and then distilled to separate the light components, resulting in industrial naphthalene with a solidification point of 78 ℃ and a purity of 96%

工業萘中含雜質硫茚（1-3%），甲基萘（1-2%）及少量茚，焦油堿和焦油酸經過進一步酸洗和蒸餾可得到硫含量小于0.1%凝固點為79℃的精萘，若需要進一步精制使硫含量低于0.05%，則需采用加氫精制工藝.

Industrial naphthalene contains impurities such as sulfur indene (1-3%), methyl naphthalene (1-2%), and a small amount of indene. Tar alkali and tar acid can be further pickled and distilled to obtain refined naphthalene with a sulfur content of less than 0.1% and a solidification point of 79 ℃. If further refinement is required to reduce the sulfur content to below 0.05%, a hydrogenation refining process is required

用工業萘小批量生產精萘的流程如下:將硫酸加入熔融的萘中脫水,攪拌后靜置分離廢酸,再加入98%的硫酸,在85-95℃條件下攪拌40分鐘,靜置分離廢酸在攪拌下加入37%的甲醛溶液在85-95℃條件下攪拌50分鐘,加溫水攪拌后靜置,分層聚合物及磺化物料.用10%氫氧化鈉溶液中和PH到7-8,靜置后除去廢堿，蒸餾冷卻可得到精萘產品.

The process of producing refined naphthalene in small batches using industrial naphthalene is as follows: sulfuric acid is added to molten naphthalene for dehydration, stirred and left to stand for separation of waste acid. Then, 98% sulfuric acid is added and stirred at 85-95 ℃ for 40 minutes. The waste acid is then left to stand for separation. 37% formaldehyde solution is added while stirring and stirred at 85-95 ℃ for 50 minutes. After stirring with warm water, the polymer and sulfonated materials are separated. The pH is neutralized to 7-8 with a 10% sodium hydroxide solution. After standing, the waste alkali is removed and distilled and cooled to obtain refined naphthalene products