从煤焦油中分离出来的萘称之为焦油萘，在高温煤焦油中萘约占8-12%，从焦油精馏塔侧线切取出温度区间为210-230℃的萘油馏分经过洗涤脱酚再精馏分离轻组分，便可得到凝固点为78℃纯度为96%的工业萘

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%

工业萘中含杂质硫茚（1-3%），甲基萘（1-2%）及少量茚，焦油碱和焦油酸经过进一步酸洗和蒸馏可得到硫含量小于0.1%凝固点为79℃的精萘，若需要进一步精制使硫含量低于0.05%，则需采用加氢精制工艺.

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

用工业萘小批量生产精萘的流程如下:将硫酸加入熔融的萘中脱水,搅拌后静置分离废酸,再加入98%的硫酸,在85-95℃条件下搅拌40分钟,静置分离废酸在搅拌下加入37%的甲醛溶液在85-95℃条件下搅拌50分钟,加温水搅拌后静置,分层聚合物及磺化物料.用10%氢氧化钠溶液中和PH到7-8,静置后除去废碱，蒸馏冷却可得到精萘产品.

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