An enantioselective allylation reaction of allylic carbonates with sodium sulfite (Na2SO3) catalyzed by Ir complex was accomplished, providing allylic sulfonic acids in good to excellent yields with a high level of enantio‐ and regioselectivities. (R)‐2‐Phenyl‐2‐sulfoacetic acid, a key intermediate for the synthesis of Cefsulodin and Sulbenicillin, was synthesized as well.
Ir配合物催化了碳酸烯丙酯与亚硫酸钠(Na 2 SO 3)的对映选择性烯丙基化反应,提供了高至优异收率的烯丙基磺酸,并具有高水平的对映和区域选择性。(R)-2-苯基-2-磺基乙酸也合成了头孢磺啶和磺基青霉素的关键中间体。
Versatility of the application of thermal analysis to the simulation of gas desulphurisation
作者:K. Wieczorek-Ciurowa
DOI:10.1016/0040-6031(95)02616-9
日期:1996.1
sulphation process of pre-calcined limestone illustrates the application of programmed thermalanalysis techniques using different gas sequences. The direct usage of commercial equipment (e.g. Derivatograph and Mettler thermoanalysers) is limited because the thermobalance unit must be additionally isolated to operate under a corrosive gas atmosphere. The TA methods are capable of predicting the behaviour
摘要 预煅烧石灰石的硫酸化过程说明了使用不同气体序列的程序化热分析技术的应用。商业设备(例如衍生仪和梅特勒热分析仪)的直接使用受到限制,因为热天平单元必须额外隔离才能在腐蚀性气体环境下运行。TA 方法能够预测潜在吸附剂在大规模安装中对 SO 2 SO 3 的行为。来自 CaSO 系统的化合物的热稳定性和添加剂对硫酸化的影响已被发现有助于阐明石灰石的硫酸化机制。热分析研究必须辅以独立的补充技术,例如 X 射线衍射、
Some aspects of calcium sulphite reduction with carbon monoxide
作者:S. Ghardashkhani、O. Lindqvist
DOI:10.1016/0040-6031(91)85258-j
日期:1991.11
corresponding multistage SO 2 release. The multistage weight loss and the corresponding SO 2 release were presumed to be the consequence of different sequential reactions taking place along with the direct reduction of CaSO 3 to CaS, including the formation and decomposition of CaCO 3 and CaSO 4 , respectively. The corresponding SO 2 evolution was found to be considerably lower at slow heating rates. In the presence
摘要 结晶CaSO 3 ·0.5H 2 O和无水CaSO 3 在CO、CO 2 和CO-CO 2 气体混合物下在25°C min -1 和6°C min 两种加热速率下的非等温还原分解反应分别采用热重分析、X 射线粉末衍射、红外光谱和通过在线荧光光谱法连续测量 SO 2 来分别研究 -1 至 900°C。在加热过程中,反应涉及多阶段重量损失,在这两种情况下,相应的多阶段 SO 2 释放。多阶段失重和相应的 SO 2 释放被认为是随着 CaSO 3 直接还原为 CaS 发生的不同顺序反应的结果,分别包括 CaCO 3 和 CaSO 4 的形成和分解。发现相应的 SO 2 放出量在缓慢加热速率下相当低。在存在额外的 CO 2 的情况下,SO 2 的释放增加,并且在 70% CO 2 和 30% CO 的进料气混合物以及纯 CO 2 中发现最高 SO 2 浓度。CaCO 3 产物也随着CO 2
The oxidation of calcium sulphite by calcium nitrate
作者:Andrew K Galwey、Clodagh Ettarh
DOI:10.1016/s0040-6031(98)00305-0
日期:1998.5
chemical changes, in which sulphite oxidation to sulphate is a dominant process, accompanied by somenitrate decomposition. On heating to higher temperatures (above 800 K) a second endothermic reaction was identified as the melting and breakdown of calcium nitrate. These processes occurred at temperatures somewhat less than those characteristic of the pure salt, possibly due to the presence of products
摘要 亚硫酸钙和硝酸钙的粉碎粉末混合物在 650 到 700 K 之间发生放热反应。已经通过动态和等温 DSC 实验研究了这种速率过程,并辅以基于真空装置中气体逸出的等温速率研究,以及一些产品分析。结论是整个反应是复杂的,包括几个同时发生的化学变化,其中亚硫酸盐氧化为硫酸盐是主要过程,伴随着一些硝酸盐分解。在加热到更高的温度(高于 800 K)时,第二个吸热反应被确定为硝酸钙的熔化和分解。这些过程发生在略低于纯盐特征的温度下,可能是由于第一反应的产物的存在,包括少量的 Ca(NO 2 ) 2 。在显着低于任一反应物熔点的温度下,主要的放热反应伴随着熔化。这可能是由于 Ca(NO 2 ) 2 中间产物的形成,熔点 551 K,或在与反应物 CaSO 3 ·1/2H 2 O 脱水过程中放出的水发生水解反应后生成液体产物,其中放热氧化重叠。该脱水步骤是亚硫酸盐氧化的前体。由于难以将贡献与几个可能
Recovery of carboxylic acid from byproduct stream
申请人:Fan Maohong
公开号:US20050049433A1
公开(公告)日:2005-03-03
A novel method for recovering carboxylic acid from a waste water stream is described. The method involves first neutralizing the carboxylic acid in the waste water with CaO or Ca(OH)
2
to form calcium carboxylate. The resulting calcium carboxylate is then reacted with sulfite or sulfate to regenerate the carboxylic acid. The resulting waste water typically has a carboxylic acid content of at least 25-wt %.