CAS号 [100-09-4] 生产工艺  对甲氧基苯甲酸

CAS名: Benzoic acid, 4-methoxy-  历史参考文献: Beil. 10, 154; E¹, 69; E², 91; E³, 280; E⁴, 346.

用途: 红色基KD。香料，防腐剂，医药（风湿药）反应类别:  羟基烷化（醚化）或氯甲氧基置换。

生产工艺参考文献:  按本人手头资料整理如下。

BIOS 1153, 44-46. （=胶卷PB 85687）p-Anisic acid.（Leverkusen）英国人译自德文（未说资料来源）。抄录如下。

反应式: 本人有加注。英国人译文未找到对应德文原件！（有两条工艺路线）。

Outline:  Methylation of p-hydroxybenzoic acid with dimethylsulphate.

Plant:  3500 l. cast steel vessel; measure vessel for dimethylsulphate. Vat, blow-egg.

Nutsche for alkaline solution. Nutsche for acid solution..

Charge:  p-Hydroxybenzoic acid moist   600 kg. 100%≈300 kg. NaNO₂.  Caustic liquor 30%    1220 kg.

Dimethylsulphate tech.   330 kg. Kieselguhr  10 kg.  Carbon 90 kg.

Hydrochloric acid (1.16)   900 l. Sulphuric acid  60⁰Be’  350 kg.

Process:

The iron vessel is charged with 800 l. of water and 1220 kg. of 30% caustic liquor and the p-hydrocybenzoic acid the added. At 98⁰, 330 kg. of dimethylsulphate are added. After 3 hours, the contents are blown hot into a vat containing 700 l. of hydrochloric acid and 300 l. of water; the vessel is washed out with 300 l. of water. The contents of the vat must be acid to Congo. After cooling to 18-20⁰ the product is filtered and the filtrate run to drain. The crude product is purified by conversion to the sodium salt.

The crude product is dissolved in a melt vessel in 250 l. of water and 500 kg. of 30% caustic liquor at 70⁰; the solution should be weakly alkaline. It is blown into an iron agitated pan and cooled to 25⁰. The crystalline mass is filtered and pulled as dry as possible but not washed. The filtrate on acidification with hydrochloric acid gives a mixture of unchanged p-hydroxybenzoic acid and p-anisic acid and is charged back to a new methylation

The sodium salt nutsche cake is dissolved in 6000 l. of water at 85⁰, 10 kg. of kieselguhr and 30 kg. of carbon added, and the solution is then screened. The press is washed with 2000 l. of hot water. The filtrate is acidified with 350 kg. of sulphuric acid 60⁰Be’ and the product cooled to 30⁰ filtered on a nutsche and washed 5-6 times with 1000 l. cold water to remove the sulphuric acid. The filtrate and washings go to drain.（抄注: 当时无三废处理！）

The p-anisic acid is dried in vacuum at 70⁰ and ground. The yield depends on the working up of a series of batches to re-use the recovered product.

The average yield is then 545 kg. 100% = 249 kg. nitrite. = 83% theory.

张澍声 编译。《精细化工中间体工业生产技术》1996年。P. 66-67.  对甲氧基苯甲酸。译自BIOS 1153, 44. 抄录如下。

对甲氧基苯甲酸是由对羟基苯甲酸用硫酸二甲酯甲基化而得。

在铁反应器中加入800 L 水，122 kg 30%氢氧化钠溶液和湿的对羟基苯甲酸，相当于600 kg 100% 产品（相当于300 kg亚钠量）。在98⁰C加入330 kg工业品硫酸二甲酯，3小时后将反应物趁热送往酸化槽中，槽中含有700 L盐酸和300 L水，反应器再用300 L水洗涤。酸化槽内物料必须对刚果红为酸性。冷至18-20⁰C后，产品过滤，滤液弃去，粗产品转化为钠盐进行精制。

粗产品溶解于250 L水中，在70⁰C加入500 kg 30% 氢氧化钠溶液，溶液应呈弱碱性。冷却到25⁰C，结晶物过滤，并尽可能压干，但不洗涤。滤液用盐酸酸化，得到未变化对羟基苯甲酸和对羟基苯甲酸的混合物，回到下一批甲基化中。

钠盐滤饼在85⁰C溶解于6000 L水中，加入10 kg 硅胶和30 kg活性炭，然后将溶液进行滤清过滤，滤渣用2000 L热水洗涤。滤液用350 kg 78% 硫酸酸化，产品冷却到30⁰C,抽滤，用1000 L冷水洗5-6次以除去硫酸，滤液和洗水均弃去。

对甲氧基苯甲酸在70⁰C真空干燥，粉碎，收率取决于许多批次的后处理及回收产品的复用。平均收率83%，相当于545 kg 100% 对甲氧基苯甲酸。  

BIOS 1605. 22. （=胶卷PB 87874）  p-Anisic acid.  英国人译自德文。（主要用于感光材料生产）本人未收藏。

FIAT 1313,I, 55-56.（=胶卷PB 85172）p-Anisic acid（I. G. Leverkusen）‘Paranisaeure’美国人译自德文。抄录如下。

Apparatus;  Nothing unusual, not copied.  Cast iron reactor.     抄注: 这里主要说明美国人对同一德文的不同译法！

Materials: 1 – 600 kg. p-hydroxybenzoic acid, 100% (300 kg. NaNO₂ eq.).   2 – 1200 kg.  NaOH, 30%. 3 – 330 kg. dimethyl-sulfate. 

4 – 10 kg. kieselguhr. 5 – 30 kg. decolorizing carbon 6 – 900 kg. HCl, 20⁰Be’. 7 – 350 l. H₂SO₄, 60⁰Be’.

Procedure:

Add (2) to reactor and than (1). At 98⁰C., add (3) gradually. Stir 3 hrs. after (3) is added. Run charge into 700 l. (6) plus 300 l. H₂O. Add 500 l. H₂O and the wash water from washing this vessel on previous batch. Test: acid to Congo. Cool to 18-20⁰C. and filter.

Purification: Dissolve crude in 500 l. NaOH solution and 250 l. H₂O at 70⁰C. Test: slightly alkaline. Cool to 25⁰C. in iron vessel and filter soda salt . No washing. Stamp dry on nutsch. Acidify the mother liquor with HCl to acid test on Congo. A mixture of methoxy and hydroxyl compounds are recovered for further methylation.

Dissolve soda salt in 6000 l. H₂O at 85⁰C. Add (4) and (5). Filter and wash clarifying press with 2000 l. hot water. Acidify solution with (7). Cool to 30⁰C. and filter. Wash product with five to six 1000 l. washes. Filter and stamp dry. The mother liquor and wash are discarded. Dry at 70⁰C. and mill.

Yield:  On a series of batches 545 kg. of 100% product, M.W. 152 are obtained. 249 kg. NaNO₂ eq. = 83% of theoretical.

PB 73491, 8689. P-Anisic acid.  德文生产工艺。未抄录。

吕玉芝 唐会林（沈阳院）。红色基KD合成新工艺探讨。[J]染料工业, 1996, 2, 37-38 (32). 甲氧基化。抄录如下。

甲氧基化:  在500 ml的三口瓶中加入对氯苯甲酸46.8 g，甲醇250 ml，助剂TR – 300  12 g。回流搅拌10小时。经后处理，得产品4-甲氧基苯甲酸41.5 g，重量收率91.3%。

加注: 

本人抄录的PB报告有两种，一种是美国人编写的目录，另一种是本人手抄的目录，前一种读者可以看到美国人的介绍，而后一种只能抄个题目了！当然，还有不少未抄录的目录（目前看来，读者没有兴趣！）。本人每天抄录的资料（含目录）是否有用，请读者评述吧！ - 一个文献抄录者，一位文献搬运工 – 在此再次谢谢大家的点读！

陈忠源  2017年8月7日       于 无锡   明辉国际。