Process for the preparation of sodium dichromate
    33.
    发明授权
    Process for the preparation of sodium dichromate 失效
    重铬酸钠的制备方法

    公开(公告)号:US5273735A

    公开(公告)日:1993-12-28

    申请号:US980142

    申请日:1992-11-23

    IPC分类号: C01G37/14 C25B1/28

    CPC分类号: C25B1/28 C01G37/14

    摘要: A process for the preparation of sodium dichromate and sodium dichromate solutions by alkaline oxidizing roasting of chromium ores, leaching resulting roast with water, adjustment of the pH to 7 to 9.5, removal of the insoluble constituents by filtration, a sodium monochromate solution containing 300 to 400 g/l of Na.sub.2 CrO.sub.4 being obtained, conversion of the monochromate ions of this solution into dichromate ions by addition of an acid and/or by electrolysis and/or by reaction with carbon dioxide under pressure and crystallization of sodium dichromate by concentration of this solution. The improvement wherein before the conversion into a sodium dichromate solution, the sodium monochromate solution is concentrated to contents of 700 to 1000 g/l of Na.sub.2 CrO.sub.4, the monochromatic ions, the solution is subsequently freed as far as possible from sodium sulphate by cooling to a temperature of below 0.degree. C. and filtration, and the residual monochromate ions which remain in the solution are converted into dichromate ions by electrolysis and/or by reaction with carbon dioxide and/or with chromic acid.

    摘要翻译: 一种通过碱性氧化焙烧铬矿石,用水浸泡,调节pH至7至9.5,通过过滤除去不溶成分的方法制备重铬酸钠和重铬酸钠溶液的方法,将含有300〜 获得400g / l的Na 2 CrO 4,通过加入酸和/或通过电解和/或通过与压力下的二氧化碳反应并通过浓缩该溶液使重结晶的重结晶,将该溶液的单色离子转化为重铬酸根离子 。 改进之前,在转化成重铬酸钠溶液之前,将单色钠溶液浓缩至700至1000g / l Na 2 CrO 4的含量,即单色离子,随后将溶液从硫酸钠中冷却至 温度低于0℃并过滤,留在溶液中的残留单色离子通过电解和/或通过与二氧化碳和/或与铬酸的反应转化为重铬酸根离子。

    Process for producing phosphonomaleic acid esters
    40.
    发明授权
    Process for producing phosphonomaleic acid esters 失效
    制备膦酰基酸酯的方法

    公开(公告)号:US4307040A

    公开(公告)日:1981-12-22

    申请号:US140891

    申请日:1980-04-16

    摘要: Novel phosphonomaleic acid esters of the formula ##STR1## in which R.sup.1 is an optionally substituted alkyl radical containing from 1 to 6 carbon atoms and, where n=0, may also be an optionally substituted aryl radical,R.sup.2, R.sup.3 and R.sup.4 each independently is an optionally substituted alkyl radical containing from 1 to 16 carbon atoms,R.sup.5 is hydrogen, an alkyl or aryl radical containing from 1 to 7 carbon atoms, andn=0 or 1,are produced by reacting a base with a 1-halogen-1-phosphonosuccinic acid ester of the formula ##STR2## in which Hal is chlorine or bromine. The esters are useful as intermediates in the synthesis of sequestrants, corrosion inhibitors, stabilizers, flameproofing agents, pharmaceuticals and pesticides.

    摘要翻译: 新颖的式“IMAGE”的膦酰基酸酯,其中R 1是含有1至6个碳原子的任选取代的烷基,并且其中n = 0也可以是任选取代的芳基,R 2,R 3和R 4各自独立地是 含有1至16个碳原子的任选取代的烷基,R 5是氢,含有1至7个碳原子的烷基或芳基,n = 0或1,通过使碱与1-卤素-1 其中Hal是氯或溴的式“IMAGE”的膦酰基琥珀酸酯。 酯可用作螯合剂,腐蚀抑制剂,稳定剂,防火剂,药物和杀虫剂合成中的中间体。