CAS号 [6251-07-6] 生产工艺      4-氨基-2,7-萘二磺酸

CAS名: 2,7-Naphthalenedisulfonic acid, 4-amino-          历史参考文献: Beil. 14, 792; E1, 741; E2, 477.

2,6-Naphthalenedisulfonic acid, 4-amino-

用途: 直接橙49。 酸性黑7, 36。       反应类别: 磺化，硝化和还原。

BIOS 1152, 36-39. （=胶卷PB 81087） 1-Naphthylamine-3,6-disulphonic acid and 1-Naphthylamine-3,7-disulphonic acid.

德文名: Freund Säure.  生产厂：Leverkusen.   英国人译自德文（无资料来源！）。   反应式: 如下：
 
General: 

Naphthalene is converted to the disulphonic acids through long heating with a large excess of H2SO4.  It is nitrated, lined out, and reduced.  The F. acid 1,37 is salted out as Na salt.  By salting the hot mother liquor and acidifying, the 1,3,6 is isolated.

Plant details:

Raw Materials:

600 kg. Naphthalene mol. 128≈ 323 kg.  NaNO2。   3000 kg.  H2SO4 96% 。   720 kg.  H2SO4 600 Be’ 。

352 kg. Mixed acid H.S.= (87.0% HNO3 .  11.0% H2SO4 .  2.0% H2O )。  200 kg.  Na2SO4 。    6000 kg.  Precipitated lime 。   600 kg. Iron powder 。

80 kg.  HCl.  19.50Be’ 。   530 kg.  Soda。   1800 kg.  Salt 。   4000 l.  Brine 。

Sulphonation and nitration:

3000 kg. of 96% H2SO4 are charged into the gas heated kettle and heated to 125℃.  To this 600 kg. of naphthalene are added in 20 minutes.  The temperature rises and is allowed to reach 140℃.  After the final addition it is heated to 158-162℃. and kept there for 14 hours, after which it is blown to the nitration vessel and cooled to 60℃.

At this temperature, and in about 1.5 hours, 728 kg. of 600Be’ H2SO4 are added so that the temperature falls to 30℃.  Then at 25-30℃. and in about 6 hours 352 kg. of mixed acid H.S. (HNO2 = 103% theory) and 213 l. of water are run in.

At the end of this period the nitration is finished and it is blown to the liming vat.

The liming vat has previously been charged with 3,800 l. of lime and water together with 200 kg. of Na2SO4.  The addition of the nitration mixture causes the temperature to rise to 70-80℃.  Liming is continued until neutral and after stirring for 0.5 hour, the gypsum is filtered.  The nutsche cake is well washed with hot water and the liquors united with the original mother liquors.

Reduction:

The vessel is charged with 1,500 l. of weak wash from the last batch reduction, 600 kg. of iron filings and 80 kg. of HCl.  The whole is brought to the boil and the nitro body gradually run in.  During the addition, steam is shut off the pan, the reaction being sufficient to keep it at the boil.  The reduction when completed is pale in colour.  The iron is now precipitated with about 530 kg. of soda ash and the mass is then filtered and washed.  The wash liquor can go forward for the next reduction.  The reduction liquors from two batches including subsequent first strong wash to give a 230Be’ solution are heated to 40℃.  Sufficient salt is then added to bring the Be’ to 300.

The 1,3,7-acid is precipitated and filtered off whilst still at 40℃. and washed with brine solution.  The first liquors, before washing, contain the equivalent of 33 g NaNO2 per l.  The liquors are made acid with HCl (Congo acid), filtered through an acid press and washed with salt water.

The yield of this crude 1,3,6-acid is 62.%.  It is purified by dissolving in sufficient hot water and 50% KOH to make a solution equivalent to 40 g. per l.  This is filtered and acidified again whilst hot, and the precipitate filtered off.

Yield of 1,3,7-acid = 17.5%.   Yield of crude 1,3,6-acid = 62.3%.   Yield of pure 1,3,6-acid = 60-55% on crude = 37.4-34.3% overall.

张澍声 《精细化工中间体及产品生产工艺》 2006年。 P. 567-568.  1-萘胺-3,6-二磺酸和1-萘胺-3,7-二磺酸。译自BIOS 1152.

萘转化为二磺酸，然后硝化，灰析并还原。1-萘胺-3,7-二磺酸以钠盐析出，热的母液盐析并酸化，分离出1-萘胺-3,6-二磺酸。

（一）磺化与硝化:  在2750 L铸铁锅（框式搅拌器，煤气加热，蛇管冷凝器）中，加入3000 kg 96% 硫酸，煤气加热到125℃，于20分钟内向硫酸中加入600 kg萘，温度上升，允许达到140℃. 加完后加热到158-162℃，在此温度保持14小时，然后压送到4500 L硝化锅中，并冷却到60℃。

在60℃于约1.5小时内加入728 kg 78% 硫酸，这样温度下降到30℃，然后在25-30℃于约6小时内加入352 kg混酸H.S.（HNO3 87.0%, H2SO4 11.0%, 水2.0%），并流入213 L水。在此阶段末期硝化介绍，压送到20 m3 灰化锅中。 灰化锅中预先已加入3800 L石灰和水以及200 kg硫酸钠，硝化混合物的加入引起温度上升到70-80℃， 继续灰化直至溶液为中性，总计使用6000 kg沉淀用石灰。搅拌半小时后，过滤除去石膏。  滤饼用热水很好洗涤，洗水与母液合并。

（二）还原:  在还原锅中加入上批还原时的洗水1500 L，600 kg 铁屑和80 kg盐酸，整个加热至沸，并逐渐流入硝化物。在加入硝化物时，关闭加热蒸汽，还原反应足以保持其沸腾状态。还原完成时颜色为灰色。用约530 kg 碳酸钠沉淀铁，物料过滤和洗涤，洗水可以用于下批还原。两批的还原溶液包括随后的第一次洗涤水一起，比重为1.189，加热到40℃，然后加入足够的食盐，使溶液比重为1.263.

1-萘胺-3,7-二磺酸纯度出来，在40℃过滤，用食盐水洗涤。洗涤前的滤液含有相当于33 g/L 亚硝酸钠的萘胺二磺酸，加盐酸使对刚果红呈酸性，压滤，用盐水洗涤。

1-萘胺-3,6-二磺酸粗品的收率为62.3%。其精制是将产品溶解在足够的热水和50%氢氧化钾中，使溶液每升相当于40 g 亚硝酸钠，过滤，趁热在酸化，将沉淀过滤。

得到：1-萘胺-3,7-二磺酸  17.5%。  1-萘胺-3,6-二磺酸粗品  62.3%。  精制品为粗品的55% -60%。

PB 25623, 509-510.  1,3,6- und 1,3,7-Freund Säure.  德文生产工艺。未抄录。

PB 25628, 3752-3756.  Freund acid. (General Aniline Works, Grasselli, N. J.  1925年5月生产工艺。1美元。 美国人介绍如下。

Freund’s acid (1-Naphthylamine-3,6- and 3,7-disulfonic acid) is produced from Naphthyl-amine, by the successive steps of Sulfonation, Nitration, liming and Reduction.  The entire process is described, and experiences with it are related.  In English.

国内申请的专利：

刘 东  马 瑛  孟明杨 等。 中国专利105777590.  一种染料中间体1-萘酚-3,6-二磺酸（RG酸）的制备方法。 2016-07-20.

本专利以2,7-萘二磺酸为原料，硝化使用催化剂磷钨酸，还原使用催化加氢法，最后采用氨基酸性水解合成目标产品，是先进的，环保的合成工艺。具体请看专利说明书，这里不再抄录。

学习与思考：

在已上网的CAS号[578-85-8] 生产工艺中，已提到萘三磺酸中，1-位磺酸基的水解可以合成目标产物，本专利是采用经硝化，还原，最后氨基水解的方法。

本人考虑的问题：研究者只提出一些如DE; Su; JP的专利文献，未提及本人所说的历史文献，今天抄录出来，想由此进行一些讨论，这类文献是否还有参考价值？按当今来说，这些资料明显过时了，但在50年以前为什么没有人了解它？

再回头来看，我们的工作结果与历史文献相比至少可以说明我们的优点在哪里。

陈忠源 （一位个体单干者）。2018年4月12日。