现行各国的精萘标准中都有酸洗比色指标，对萘中某些杂质来说，它是一个很敏感的定性指标；从工艺原理上讲，精萘厂家认为其精制不论是采用静态或动态结晶，都是利用萘与杂质的结晶点不同进行分离，那么残留在萘中的杂质组分也应类似，酸洗比色后的颜色基调应该比较接近。

The current standards for refined naphthalene in various countries have acid washing colorimetric indicators, which are sensitive qualitative indicators for certain impurities in naphthalene; From the perspective of process principle, the refined naphthalene manufacturer believes that whether it uses static or dynamic crystallization for refining, it is separated by using the different crystallization points of Cai and impurities. Therefore, the remaining impurity components in Cai should also be similar, and the color tone after acid washing and colorimetry should be relatively similar.

国内现行采用结晶法生产精茶的酸洗比色情况颜色不一，红黄紫灰等五颜六色。萘精制无论是化学法或物理法，硫茚均为主要杂质。如果显色基团是硫茚的话，颜色基调应该统一，就不会出现红黄紫灰，说明可能还存在别的显色基团即其它杂质。对精萘中可能存在的某些杂质分别做酸洗比色试验，硫茚为主要显色基团，酸化后颜色为紫红色。硫茚含量越高，试样反应后颜色越深，但硫茚不是唯一的显色基团。

The current use of crystallization method in the production of refined tea in China varies in color compared to acid washing, with various colors such as red, yellow, purple, and gray. Naphthalene refining, whether through chemical or physical methods, is mainly composed of sulfur indene as an impurity. If the chromogenic group is sulfhydrin, the color tone should be uniform, so that there will be no red, yellow, purple, or gray, indicating that there may be other chromogenic groups or impurities present. Perform acid washing colorimetric tests on certain impurities that may exist in refined naphthalene, with thionines as the main chromogenic group and the color after acidification being purple red. The higher the content of thionines, the darker the color of the sample after reaction, but thionines are not the only chromogenic group.

硫茚比恭容易磺化，在80C下和浓硫酸反应即产生:一元二元二元磺酸混合物。在酸的催化作用下硫茚本身易聚合。

Thiindene is more prone to sulfonation than Gong, and reacts with concentrated sulfuric acid at 80C to produce a binary sulfonic acid mixture. Under the catalysis of acids, thionines themselves are prone to polymerization.

虽然硫茚是精萘中的主要杂质和显色基团，但是影响精萘酸洗比色和使用性能的还有存在于茶中的不饱和化合物，也是显色基团，主要是甲基茚和甲基氧茚，如二甲基氧茚与浓硫酸作用后生成二元三元四元的聚合体，二甲基茚与浓硫酸作用后聚合成1~50个以上单体连接的聚合体。

Although thioindene is the main impurity and color developing group in refined naphthalene, the unsaturated compound existing in tea also affects the color comparison and use performance of refined naphthalene in acid pickling. It is also a color developing group, mainly methylindene and methyloxyindene. For example, after the reaction of dimethyloxyindene with concentrated sulfuric acid, binary ternary quaternary polymers are generated, and after the reaction of dimethylindene with concentrated sulfuric acid, more than 1~50 monomers are polymerized.

其采用酸洗法精制就是此化学原理。在精恭中由于不饱和化合物的含量低，组份复杂，用常规检验方法直接测定有困难，但是可以通过测定精萘中表示不饱化合物的“碘价”来反应它们含量大小。

The use of acid washing method for refining is based on this chemical principle. Due to the low content of unsaturated compound in refined naphthalene and the complex composition, it is difficult to directly determine them with conventional inspection methods, but their content can be determined by determining the "iodine value" of the unsaturated compounds in refined naphthalene.

萘酚的生产实践证明，用酸洗法生产的二级精萘(酸洗法比结晶法一般硫茚含量偏高，但不饱和化合物含量低)，硫茚含量在1.2%~1.5%。

The production practice of naphthol proves that the secondary refined naphthalene produced by acid washing method (the acid washing method is higher than the crystallization method, but the content of unsaturated compound is lower), and the content of thioindene is 1.2%~1.5%.

萘酚生产正常，而用不饱和化合物含量.高(即碘价高)的精萘生产萘酚，会产生树脂状物，影响过滤甚至堵塞管道等问题。这说明不饱和化合物对精茶的酸洗比色和使用性能会产生很大的影响。更多相关内容就来我们网站http://www.jnjdbc.cn咨询吧!

The production of naphthol is normal, but the production of naphthol with refined naphthalene with high unsaturated compound content (i.e. high iodine price) will produce resinous substances, affect filtration and even block pipes. This shows that unsaturated compound will have a great impact on the pickling colorimetry and use performance of refined tea. For more related content, come to our website http://www.jnjdbc.cn Consult!