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文章以粗蒽为原料、DMF复配溶剂的最佳结晶条件是保温温度为90℃,保温时间50min,冷却结晶温度为25℃,保温时间50min,固液比1.8g/ml。结果表明:这一方法使溶剂得以循环利用,环境污染小,且成本低,精蒽的纯度可达96%以上,收率达到67%以上。 相似文献
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采用碱浸酸析的方法从红橘果皮中提取橙皮苷．通过对碱的种类、添加量、料液比、提取时间、反应体系pH值及提取温度等因素的研究,确定提取橙皮苷的最佳工艺条件为：温度在30℃,在25g的橘皮粉中加入750g蒸馏水,1．75g氢氧化钙,搅拌浸提0．5h,酸析的pH值为3,粗产品收率为4．2％．粗产品经过重结晶分离提纯,收率达到56％,产品结构经过IR鉴定． 相似文献
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氰尿酸合成新工艺的研究 总被引：2，自引：0，他引：2
用DMF和十二烷基苯作混合溶剂合成氰尿酸，通过实验确定了最佳反应工艺条件，氰尿酸的产率可达95％，纯度可达98％，合成氰尿酸的工艺条件温和，适合工业化生产。 相似文献
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A large amount of residue including benzoic acid, benzyl benzoate and fluorenone can form in the production of benzoic acid
by oxidizing toluene. To recycle the resources and reduce secondary pollution, the treatment of benzoic acid residue was carried
out to obtain the three purified materials by flash-vacuum distillation combination method, and the influence of the operating
parameters, such as the top pressure, reflux ratio and top and bottom temperatures was investigated to obtain the best operating
conditions. The experimental results show that the benzoic acid purity can reach 97% through distillation under the following
conditions: the top pressure is 1 600 Pa, the bottom temperature is 190–200 °C, the top temperature is 130–135 °C, and reflux
ratio is 5:1. The best operating conditions for benzyl benzoate distillation column are: the top pressure is 400 Pa, bottom
temperature is 250–260 °C, the top temperature is 150–160 °C, and reflux ratio is 5:1. The benzyl benzoate purity can reach
95% and the fluorenone purity can reach 92%. When refined by melt crystallization, the benzoic acid purity can be improved
up to 99.6%, and the purities of benzyl benzoate and fluorenone are both above 95%. 相似文献
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以磷钨杂多酸为催化剂,通过乙酸和正己醇的酯化反应合成了乙酸正己酯,并对影响酯化率的因素进行了研究.结果表明:反应的最佳条件为:乙酸为0.1 mol时,醇酸物质的量比为1.4,催化剂用量为0.3 g,带水剂为15 mL,在温度为110~130℃下,反应30 min,酯化率可达99.6%以上. 相似文献
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制备了活性炭固载对甲苯磺酸催化剂,以乙酸和正己醇为原料合成了乙酸正己酯,考察了影响酯化率的各种因素,确定了最佳反应条件为:乙酸用量为0.1 mol时,醇酸物质的量比为1.4,催化剂用量为3 g,15 mL甲苯作带水剂,反应时间30 min,酯化率达94%以上. 相似文献
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以五氧化二钒为原料,研究了制备硫酸氧钒的方法,并研究了硫酸氧钒中钒含量的测定方法．五氧化二钒经浓硫酸溶解活化后,经草酸还原等系列实验过程制备高纯度的硫酸氧钒蓝色晶体．考察了反应温度对反应的影响,结果显示在90~C条件下,硫酸氧钒产率为92．13％．将制得的硫酸氧钒试样经高锰酸钾氧化,用亚硝酸钠、尿素除去干扰物,以邻苯氨基苯甲酸作指示剂,在pH=0的酸性条件下,用硫酸亚铁氨溶液进行滴定,测得钒的含量约为29．56％,表明所制备的样品纯度较高． 相似文献
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Diisopropylidenated α-D-glucofuranose (1) was oxidated with CrO3-pyridine complex.Oxidated product and its hydrate were separated and were reduced together to synthesize diisopropylidenated α-D-allofuranose (3). The yield of 3 increased by 8% than that with only oxidated product as reduction substrate. Benzoylated derivative of 3 was selectively hydrolyzed and dimesylated to synthesize 3-O-benzoyl-1,2- O- isopropylidene-α-D-allofuranose (5) and its dimesylated deriva tive respectively. The overall yield of 5 from 1 was 36%. Each step and final products were anal yzed by 1H-NMR spectra and other methods. The experiments showed that the influence of acetic acid concentration on selective hydrolysis was obvious. The hydrolysis yield was 81.8%. Oxidation, reduction and other procedures were practical and had application potential. 相似文献
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Diisopropylidenated a-D-glucofuranose (1) was oxidated with CrO;-Pyridine complex. Oxidated product and its hydrate were separated and were reduced together to synthesize diisopro-pylidenated a-D-allofuranose (3 ). The yield of 3 increased by 8% than that with only oxidated prod-uct as reduction substrate. Benzoylated derivative of 3 was selectively hydrolyzed and dimesylated to synthesize 3-O-benzoyl-l ,2-O-isopropylidene-a-D-allofuranose (5) and its dimesylated deriva-tive respectively. The overall yield of 5 from 1 was 36%. Each step and final products were analyzed by 'H-NMR spectra and other methods. The experiments showed that the influence of acetic acid concentration on selective hydrolysis was obvious. The hydrolysis yield was 81. 8%. Oxidation, re-duction and other procedures were practical and had application potential. 相似文献
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用干灰化法将三乙酰氧基硼氢化钠中的有机硼转化为硼酸盐,在适宜的pH条件下,将硼酸盐转化为硼酸,用甘露醇强化硼酸的酸性,酸碱滴定法确定硼酸的含量,计算出三乙酰氧基硼氢化钠的含量.此方法的精密度、准确度良好.标准偏差为0.39%,相对标准偏差为0.39%,回收率为100%. 相似文献
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制备了负载型对甲苯磺酸催化剂 ,发现P -TsOH/C具有催化活性高的特点 .以P -TsOH/C作为丙烯酸与三羟甲基丙烷的酯化催化剂 ,研究了醇酸比、酯化时间、催化剂用量对反应的影响 ,并选择了最佳反应条件 ;在此条件下 ,酯化率达 95 .2 %以上 ,酯纯度在 98%以上 ,而且催化剂可以重复使用多次 . 相似文献
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磷钨杂多酸催化合成富马酸二甲酯 总被引：1，自引：1，他引：1
研究了以磷钨杂多酸为催化剂,以马来酸酐和甲醇为原料合成富马酸二甲酯.反应的最佳条件是:马来酸酐和甲醇的物质的量比为1∶6,催化剂用量为马来酸酐质量的8%,反应时间6h,产率达91.7%. 相似文献
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研究了用硫酸氢钠催化合成环已酮1，2—丙二醇缩酮，详细探索了影响缩合反应的各种因素。得出了硫酸氢钠催化合成环已酮1，2—丙二醇缩酮反应的最佳条件：以环已酮0．2摩尔为标准，酮／醇(摩尔比)为1：1．5，硫酸氢钠催化剂和带水剂环已烷的用量为反应物总质量的1．21％、总体积的41．7％，回流反应2h，环已酮1，2—丙二醇缩酮的产率达78％。 相似文献
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无机纸层析实验过程中产生大量的丙酮废液,针对其直接分馏回收率低(21%),回收后残液达不到排放要求的问题,提出一种改进方法——溶盐分馏法。该方法根据废液含有强酸的特性,采用不同浓度的氢氧化钠中和废液中的酸,分别对酸碱中和产生的溶盐废液和盐沉淀过滤后的废液进行溶盐分馏和普通分馏。实验结果表明,溶盐分馏产品回收率达91%,纯度达99.52%,与普通分流相比,产品回收率平均提高8%,纯度提高0.39%。经估算,每回收500 ml丙酮相比委外加工处理节省实验费用约20元。 相似文献
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将含铬废液浓缩后,在弱碱性条件下将沉淀过滤。沉淀在酸性条件下加热溶解氧化后再次过滤除出沉淀,两次 滤液合并。用稀硫酸调节到PH=2,蒸发水并冷却到室温结晶,再经重结晶提纯得到产品重铬酸钾,经分析,产品纯度达96％ 以上。 相似文献
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耐寒增塑剂癸二酸二己酯的催化合成研究 总被引：2，自引：0，他引：2
以硅钨杂多酸为催化剂，癸二酸和正己醇为原料合成了癸二酸二己酯．考察了醇酸物质的量比、催化剂用量、反应时间等因素对酯化率的影响．结果表明，在适宜的条件下其酯化率可达95％以上。 相似文献