Naphthalene, also known as naphthalene, is a colorless and shiny flake crystal. Insoluble in water, easy to sublimate, can volatilize with water vapor and has a special smell. It is an important polycyclic aromatic hydrocarbon in industry. It can be used in the production of phthalic anhydride, dye intermediates, rubber additives and pesticides. According to different purity, naphthalene can be divided into industrial naphthalene and refined naphthalene. The purity of industrial naphthalene is generally about 96%. After further purification, impurity removal and desulfurization of industrial naphthalene, high-purity refined naphthalene can be obtained.

白色易揮發(fā)晶體，有溫和芳香氣味，粗萘有煤焦油臭味；蒸汽壓0.13kPa/52.6℃閃點(diǎn)：80℃；熔點(diǎn)80.1℃沸點(diǎn)217.9℃；不溶于水，溶于無水乙醇、醚、苯，相對密度（水=1）1.16;相對密度（空氣=1）。穩(wěn)定性：穩(wěn)定；危險標(biāo)記：（易燃固體）；主要用途：用于制造染料中間體、皮革、木材保護(hù)劑等。

White volatile crystal with mild aromatic smell, crude naphthalene with coal tar smell; Steam pressure: 0.13kpa/52.6 ℃, flash point: 80 ℃; Melting point 80.1 ℃, boiling point 217.9 ℃; Insoluble in water, soluble in absolute ethanol, ether and benzene, relative density (water = 1) 1.16; Relative density (air = 1). Stability: stable; Hazard marking: (flammable solid); Main uses: used for manufacturing dye intermediates, leather, wood protectants, etc.

焦油萘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(cè)線切取出溫度區(qū)間為210-230℃的萘油餾分，經(jīng)過洗滌脫酚，再精餾分離輕組分，便可得到凝固點(diǎn)為78℃、純度為96%的工業(yè)萘。

Tar naphthalene the naphthalene separated from coal tar is called tar naphthalene. Naphthalene accounts for about 8-12% in high-temperature coal tar. The naphthalene oil fraction with temperature range of 210-230 ℃ is cut from the side line of tar distillation tower, washed and dephenolized, and then the light components are separated by distillation to obtain industrial naphthalene with freezing point of 78 ℃ and purity of 96%.

工業(yè)萘中含雜質(zhì)硫茚（1-3%）、甲基萘（1-2%）及少量茚、焦油堿和焦油酸，經(jīng)過進(jìn)一步酸洗和蒸餾，可得到硫含量小于0.1%、凝固點(diǎn)為79℃的精萘。若需要進(jìn)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 indene (1-3%), methylnaphthalene (1-2%) and a small amount of indene, tar alkali and pyrooleic acid. After further pickling and distillation, refined naphthalene with sulfur content less than 0.1% and freezing point of 79 ℃ can be obtained. If further refining is required to make the sulfur content less than 0.05%, hydrofining process shall be adopted.

用工業(yè)萘小批量生產(chǎn)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?dāng)嚢韬箪o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(chǎn)品。

The process of small batch production of refined naphthalene from industrial naphthalene is as follows: add sulfuric acid into molten naphthalene for dehydration, stir and stand to separate waste acid. Add 98% sulfuric acid, stir at 85-95 ℃ for 40 minutes, and stand to separate the waste acid. Add 37% formaldehyde solution under stirring, stir at 85-95 ℃ for 50 minutes, stir with warm water and stand, and layer the polymer and sulfonated material. Neutralize pH to 7-8 with 10% sodium hydroxide solution, and remove waste alkali after standing. Refined naphthalene can be obtained by distillation and cooling.

石油萘石油萘的原料來自于催化重整、催化裂化和烴類裂解等過程的重芳烴組分。在催化重整油中，甲基萘的含量約為55%.首先經(jīng)過萃取和吸附，從原料餾分中分離出萘的各種同系物，然后采用催化臨氫脫烷基的方法。

Petroleum naphthalene the raw material of petroleum naphthalene comes from heavy aromatic components in catalytic reforming, catalytic cracking and hydrocarbon cracking. In the catalytic reforming oil, the content of Methylnaphthalene is about 55%. Firstly, various homologues of naphthalene are separated from the raw material fraction through extraction and adsorption, and then the catalytic hydrodealkylation method is adopted.

以Cr2O3-Al2O3為催化劑，在400-800℃和0.5-7兆帕下進(jìn)行臨氫脫甲基反應(yīng)，反應(yīng)產(chǎn)物經(jīng)冷卻氣相物質(zhì)后，蒸餾除去輕組分苯、甲苯、二甲苯等，進(jìn)一步精餾可得到石油萘產(chǎn)品。產(chǎn)品用溶劑吸收和溶劑洗滌的方法進(jìn)行提純，純度可達(dá)99.73%.

With Cr2O3-Al2O3 as catalyst, the hydrodemethylation reaction is carried out at 400-800 ℃ and 0.5-7 MPa. After cooling the gas phase substances, the reaction products are distilled to remove the light components such as benzene, toluene and xylene. Petroleum naphthalene products can be obtained by further distillation. The product was purified by solvent absorption and solvent washing, and the purity was 99.73%