Process for the production of sodium dichromate
    52.
    发明授权
    Process for the production of sodium dichromate 失效
    生产重铬酸钠的方法

    公开(公告)号:US5250274A

    公开(公告)日:1993-10-05

    申请号:US824682

    申请日:1992-01-21

    IPC分类号: C01G37/14 C01G37/00

    CPC分类号: C01G37/14

    摘要: The invention relates to a process for the production of sodium dichromate and sodium dichromate solutions by oxidative roasting of chrome ores under alkaline conditions, leaching of the furnace clinker obtained with water or an aqueous chromate-containing solution, adjustment of the pH to from 7 to 9.5, removal of the insoluble constituents by filtration, a sodium monochromate solution being obtained, conversion of the monochromate ions of this solution into dichromate ions by acidification and crystallization of sodium dichromate by concentration of this solution, characterized in that the acidification is carried out with carbon dioxide under pressure with removal of sodium hydrogen carbonate, the remaining solution is then very largely freed from sodium monochromate by cooling to a temperature below 10.degree. C. and filtration, any monochromate ions still present in the remaining solution are converted into dichromate ions by addition of an acid and the sodium monochromate filtered off is added to the sodium monochromate solution before conversion with carbon dioxide into a sodium dichromate solution.

    摘要翻译: 本发明涉及一种通过在碱性条件下对铬矿进行氧化焙烧生产重铬酸钠和重铬酸钠溶液的方法,用水或含铬酸盐水溶液浸取得到的炉渣,将pH调节至7至 9.5,通过过滤除去不溶性成分,得到单色钠溶液,通过浓缩该溶液酸化并重结晶重铬酸钠,将该溶液的单色离子转化为重铬酸根离子,其特征在于酸化是用 二氧化碳在压力下除去碳酸氢钠,剩余的溶液然后通过冷却到低于10℃的温度非常大地从单色钠中除去并过滤,剩余溶液中仍然存在的任何单色离子被转化成重铬酸根离子 加入酸和过滤的单色钠 在将二氧化碳转化成重铬酸钠溶液之前,将f加入到单色钠溶液中。

    Process for the preparation of alkali metal salts of
2-phosphonobutane-1,2,4-tricarboxylic acid
    53.
    发明授权
    Process for the preparation of alkali metal salts of 2-phosphonobutane-1,2,4-tricarboxylic acid 失效
    制备2-膦酰基-1,2,4-三羧酸的碱金属盐的方法

    公开(公告)号:US5233088A

    公开(公告)日:1993-08-03

    申请号:US746841

    申请日:1991-08-19

    IPC分类号: C07F9/38

    CPC分类号: C07F9/3808

    摘要: The present invention relates to a process for the preparation of alkali metal salts of 2-phosphonobutane-1,2,4-tricarboxylic acid, characterized in that 2-phosphonobutane-1,2,4-tricarboxylic acid penta-alkyl esters or partial esters are reacted with an aqueous alkali metal hydroxide solution in a ratio of from 0.5 to 0.76 mol, preferably from 0.6 to 0.7 mol of alkali metal hydroxide per mol of ester function at temperatures from 20.degree. to 200.degree. C. in a one-shot process.

    摘要翻译: 本发明涉及2-膦酰基丁烷-1,2,4-三羧酸的碱金属盐的制备方法,其特征在于2-膦酰基丁烷-1,2,4-三羧酸五烷基酯或偏酯 在一步法中在20℃至200℃的温度下,每摩尔酯官能团与碱金属氢氧化物水溶液的比例为0.5至0.76摩尔,优选0.6至0.7摩尔碱金属氢氧化物。 。

    Process for the preparation of chromic acid
    54.
    发明授权
    Process for the preparation of chromic acid 失效
    制备色素的方法

    公开(公告)号:US5181994A

    公开(公告)日:1993-01-26

    申请号:US625715

    申请日:1990-12-11

    CPC分类号: C25C1/10 C01G37/033 C25B1/22

    摘要: A process for the production of chromic acid, comprisinga) dissolving ferrochrome in sulphuric acid, optionally with the addition of catholyte and/or anolyte overflow from the electrolysis,b) removing undissolved constituents by filtration,c) adding a reducing agent in a quantity more than equivalent to the quantity of iron(III) and chromium(IV) in the solution,d) precipitating chromium(III) hydroxide by raising the pH to about 4-6 by the addition of a base while maintaining the reducing conditions in the solution,e) separating the precipitated chromium hydroxide while maintaining the reducing conditions,f) working up the aqueous solution containing iron by oxidation; precipitating iron(III) hydroxide or iron(III) oxide and optionally isolating the sulphate in the solution as sodium sulphate, ammonium sulphate or calcium sulphate,g) dissolving the separated chromium hydroxide in chromic acid and optionally sulphuric acid where either a single solution in chromic acid is produced or two solutions are produced, one in chromic acid and another in sulphuric acid,h) separating the solution(s) from undissolved constituents andi) employing the chromium hydroxide solution in chromic acid as anolyte in the electrolytic production of chromic acid in an electrolytic cell divided by a membrane, and either using the same solution as catholyte in the electrolytic cell divided by a membrane or using the chromium hydroxide solution in sulphuric acid as catholyte in the electrolytic cell divided by a membrane, hydrogen and/or metallic chromium being deposited electrolytically at the cathode and/or chromium(II) ions being produced electrolytically.

    摘要翻译: 一种生产铬酸的方法,包括:a)将铬铁溶解在硫酸中,任选地从电解中加入阴极电解液和/或阳极电解液溢出物,b)通过过滤除去未溶解的组分,c)加入一定量的还原剂 大于等于溶液中铁(III)和铬(IV)的量,d)通过加入碱将pH升高至约4-6,沉淀出氢氧化铬(III),同时保持其中的还原条件 e)在保持还原条件的同时分离沉淀的氢氧化铬,f)通过氧化处理含铁的水溶液; 沉淀氧化铁(III)或氧化铁(III),并任选地将溶液中的硫酸盐分离为硫酸钠,硫酸铵或硫酸钙,g)将分离的氢氧化铬溶解在铬酸和任选的硫酸中, 产生铬酸或产生两种溶液,一种在铬酸中,另一种在硫酸中,h)将溶液与未溶解的组分分离,以及i)在铬酸的电解生产中使用铬酸中的氢氧化铬溶液作为阳极电解液 在电解槽中除以膜,在电解槽中用阴离子电解液分隔膜或使用硫酸中的氢氧化铬溶液作为阴极电解液,在电解槽中被膜,氢和/或 阴极电解沉积的金属铬和/或电解产生的铬(II)离子。

    Electrochemical process for the production of chromic acid
    57.
    发明授权
    Electrochemical process for the production of chromic acid 失效
    电化学工艺生产氯酸

    公开(公告)号:US5068015A

    公开(公告)日:1991-11-26

    申请号:US393733

    申请日:1989-08-15

    IPC分类号: C25B1/00 C25B1/22 C25B15/08

    CPC分类号: C25B1/22

    摘要: A process for the production of chromic acid by the multistage electrolysis of dichromate and/or monochromate solutions in two-compartment electrolysis cells, of which the anode and cathode compartments are separated by cation exchanger membranes, at temperatures in the range from 50.degree. to 90.degree. C., the dichromate and/or monochromate solutions being obtained by the digestion of chrome ores and leaching, the improvement wherein, optionally after the removal of aluminum, vanadium and other impurities, the monochromate solution obtained after leaching is adjusted at 20.degree. to 110.degree. C. to a pH value of from 8 to 12 by the addition and/or in situ formation of carbonate in a quantity of from 0.01 to 0.18 mol/l (for 300 to 500 g/l Na.sub.2 CrO.sub.4, converted with CO.sub.2 under pressure into a dichromate-containing solution, the dichromate-containing solution is introduced into the anode compartment of the electrolysis cell, a solution containing chromic acid, in which the molar ratio of Na ions to chromic acid is from 0.45:0.55 to 0.30:0.70, is electrolytically produced and the chromic acid is worked up by crystallization, washing and drying.

    摘要翻译: 通过在两室电解池中的重铬酸盐和/或单色溶液的多级电解生产铬酸的方法,其中阳极和阴极室由阳离子交换膜分离,温度范围为50至90℃ ℃,通过铬矿和沥滤的消解获得的重铬酸盐和/或单色溶液,其中任选地在除去铝,钒和其它杂质之后,将浸出后获得的单色溶液调节至20℃至 通过加入和/或原位形成量为0.01至0.18mol / l的碳酸盐(对于300至500g / l的Na 2 CrO 4,在压力下用CO 2转化),将pH值为8至12 将含有重铬酸盐的溶液引入电解槽的阳极室中,将含有铬酸的溶液与Na离子的摩尔比 欧米酸为0.45:0.55-0.30:0.70,经电解生产,铬酸通过结晶,洗涤和干燥处理。

    Process for the preparation of dimethylmaleate
    59.
    发明授权
    Process for the preparation of dimethylmaleate 失效
    马来酸二甲酯的制备方法

    公开(公告)号:US4827022A

    公开(公告)日:1989-05-02

    申请号:US171400

    申请日:1988-03-21

    CPC分类号: C07C69/60 C07C67/08

    摘要: An improved process for the preparation of dimethylmaleate by the esterification of maleic acid anhydride, maleic acid monomethylester, maleic acid or mixtures thereof with methanol in the presence of catalytic quantities of sulphuric acid, which comprises carrying out the esterification reaction within 20 to 120 minutes in a multistage bubble cap column reactor at temperatures of from 90.degree. to 140.degree. C. and with methanol excesses of from 0.4 to 2.0 mole per mole of the dimethylmaleate to be produced.

    摘要翻译: 马来酸酐,马来酸单甲酯,马来酸或其与甲醇的混合物在催化量的硫酸存在下酯化制备马来酸二甲酯的改进方法,其包括在20至120分钟内进行酯化反应 多级泡罩塔式反应器,温度为90至140℃,每摩尔马来酸二甲酯的甲醇过量为0.4至2.0摩尔。