共查询到18条相似文献,搜索用时 78 毫秒
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高效液相色谱法测定精对苯二甲酸中微量杂质 总被引:6,自引:0,他引:6
建立了高效液相色谱法(HPLC)同时测定精对-苯二甲酸(PTA)中微量杂质4-羧基苯甲醛(4-CBA)、对-甲基苯甲酸(P-TOL)和苯甲酸(C7H6O2)含量的方法。采用的色谱柱为Shim-PackWAX-1柱,流动相为0.1mol/L NH3H2PO4 6%CH3OH,(pH4.5),检测波长为254nm。PTA中微量杂质4-CBA、P-TOL和C7H6O2的含量分别为0.59-235.20mg/kg、4.52-392.00mg/kg和0.28-24.55mg/kg时线性关系良好,其线性相关系数分别为0.9998、0.9997和0.9999。苯甲酸加样平均回收率99.03%,RSD0.37%。 相似文献
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羟胺酸钴配合物催化对二甲苯氧化的研究 总被引:1,自引:0,他引:1
利用羟胺酸BPHA(N 苯甲酰基 N 苯基羟胺)钴配合物Co(BPHA)2作催化剂,对对二甲苯液相氧化反应进行了研究.详细考察了反应温度、催化剂浓度、配体浓度、反应时间和轴配体对该催化反应的影响.实验结果表明:当反应温度为125℃、氧气压力为0.5MPa、催化剂浓度为1.0×10-3mol/L、配体与催化剂的摩尔比为2∶1时、添加四甘醇或聚乙二醇作配体,反应2h时对二甲苯转化率可达41~43%、选择性为92%.本研究丰富了二甲苯选择性氧化的内容,并具有一定的工业应用前景. 相似文献
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采用双波长高效液相色谱法同时测定对二甲苯及其氧化产物的含量。通过二极管阵列检测器进行光谱扫描,选择在210nm下检测对甲基苯甲醇和对二甲苯,在254nm检测其余物质。优化了流动相及其梯度洗脱程序,将流动相乙腈比例降至20%~30%,各色谱峰能实现较好的分离。采用液相色谱法和气相色谱-质谱法研究了溶剂对对羧基苯甲醛和对甲基苯甲醛的影响。对羧基苯甲醛和对甲基苯甲醛可与溶剂甲醇反应生成缩醛。方法的检出限(3S/N)为0.07~0.8mg·L-1。各物质的回收率在99.2%~100%之间,相对标准偏差(n=6)小于2.5%。 相似文献
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- hydroxybenzaldehyde,vanillin and syringaldehyde etc. were separated on a Novapak C18 column (5μ 3. 9mm i. d.× 150mm) and eluted with MeOH-H2O (25:75, V/V) at a flow rate of 0. 6mL/min and detected at 254nm. Quantitative analysis was performed with piperonal instead of synthetic product . m-meconin,as the internal standard. Recoveries are 95%-98% and CV≤1%. The method is simple,rapid and reliable. 相似文献
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利用高效液相色谱,采用以苯甲酸为内标,分析了苯胲电解液中的对氨基苯酚、苯胺、苯胲及硝基苯的含量。紫外检测器检测波长为254nm,色谱柱为μ-Bondapak C18柱,采用0.05mol/L磷酸二氢钾缓冲液(pH3.5) 甲醇(70 30)为流动相,其流速为1.0mL/min,柱温为室温,对样品进行分析。求出待测组分对氨基苯酚,苯胺,苯胲及硝基苯的回归方程分别为,y=12.75x 0.60,y=2.84x-1.38,y=10.14x 4.33,y=37.46x 3.71,其相应的相关系数依次为0.9995,0.9992,0.9980,0.9981。上述待测组分对内标的相对校正因子分别为2.416,2.176,0.5453,0.1624。 相似文献
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Young-Lae Kim Seung Joon Chung Jae-Duck Kim Jong Sung Lim Youn-Woo Lee Sung-Chul Yi 《Reaction Kinetics and Catalysis Letters》2002,77(1):35-42
In sub- and supercritical water, partial oxidation of p-xylene was performed in a batch reactor without a catalyst at 240-500oC, 220-300 bar. The loaded amount of hydrogen peroxide was set to 0-100% of the theoretically required oxygen amount. Conversion of p-xylene was reached over 99% within 15-20 min. In sub- and supercritical water, we propose two parallel pathways and major products that consist of p-tolualdehyde, p-toluic acid, terephthalic acid, toluene and benzaldehyde. Yields of major products in subcritical conditions were higher than in a supercritical conditions. 相似文献
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建立了测定甘油催化氧化产物中H2CO3和HCOOH的离子排斥色谱分析方法。采用离子排斥柱分离,分别用纯水和4 mmol/L HCl作流动相进行H2CO3和HCOOH的分析。检测方式为非抑制电导检测。实验结果显示,H2CO3和HCOOH工作曲线的线性范围为2~100 mg/L和6.23~124.6 mg/L,检出限分别为0.45 mg/L和2.49 mg/L(S/N=3)。H2CO3的保留时间和峰面积的相对标准偏差分别为0.07%和4.0%,HCOOH的保留时间和峰面积的相对标准偏差分别为0.09%和2.2%。方法已用于甘油催化氧化产物中H2CO3和HCOOH的分析。 相似文献
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本文将苯并-10-氮杂-15-冠-5或吗啉基取代的单Schiff碱过渡配合物作为催化剂,在常压和120℃条件下,以空气为氧源,研究了对二甲苯催化氧化反应。实验探讨了Schiff碱配合物中心金属离子、Schiff碱配体中挂接的氮杂冠醚环、配体芳环上取代基和反应时间等对对二甲苯催化氧化反应的影响。实验结果表明:Schiff碱配合物中氮杂冠醚的存在能显著缩短反应诱导期,提高催化反应活性和产物选择性;Schiff碱Mn(III)配合物比Schiff碱Co(II)具有更高的催化反应活性;氮杂冠醚Schiff碱Mn(III)配合物对于二甲苯的催化氧化反应转化率大于60%,对甲苯甲酸产物的选择性均高于70%。 相似文献
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Kinetics of p-xylene oxidation in an aqueous system catalyzed by cobalt oxide have been studied at 140 °C under oxygen. The reaction is second order in p-xylene and first order in cobalt oxide concentration. The rate constant and product distribution are very close to those found for homogeneous catalytic reactions. Based on these findings, a reaction scheme describing the influence of oxide catalyst is formulated. - , , 140° C . - . , . , . 相似文献
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将一系列苯并-10-氮杂-15-冠-5或吗啉基取代的不对称双Schiff碱配合物作为催化剂,在常压和120℃条件下用于催化氧化对二甲苯研究。探讨了Schiff配合物中心金属离子、Schiff碱配体中挂接的氮杂冠醚环、配体芳环上取代基等对催化氧化对二甲苯反应活性及其氧化产物选择性的影响。实验结果表明:配合物中氮杂冠醚的存在能显著缩短反应诱导期、提高催化活性和选择性;Schiff碱Mn(Ⅲ)配合物比Schiff碱Co(Ⅱ)和Schiff碱Cu(Ⅱ)具有更高的催化活性;氮杂冠醚Schiff碱Mn(Ⅲ)配合物催化氧化二甲苯的转化率和产物选择性分别达75%和90%。 相似文献
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Analysis of cholesterol oxidation products by Fast gas chromatography/mass spectrometry 总被引:1,自引:0,他引:1
Cardenia V Rodriguez-Estrada MT Baldacci E Savioli S Lercker G 《Journal of separation science》2012,35(3):424-430
The aim of the present study was to set‐up a Fast gas chromatography/mass spectrometry method for the analysis of cholesterol oxidation products (COPs). A silylated mixture of seven oxysterol standards was injected into a Fast GC/MS system. A capillary GC column (10 m×0.1 mm internal diameter×0.1 μm film thickness) coated with 95% dimethyl‐ and 5% diphenyl‐polysiloxane, was used. The method gave a fast (total analysis time=3.5 min) and satisfactory resolution (R>1.2) of the COPs standards, with a good repeatability and sensitivity, similar to those of conventional GC/MS; recoveries were tested on mice liver. Fast GC/MS method suitability for COPs analysis in food was also tested on an oxidized sardine fillet, which had been previously saponified and purified by NH2 solid‐phase extraction (SPE); a good repeatability and sensitivity was also obtained. The analytical performance of the Fast GC/MS method for the determination of COPs, together with the consequent significant reduction of the analysis time and consumables, demonstrates that Fast GC/MS represents a valid alternative to conventional GC/MS and evinces the great potential of such an analytical technique, which could be applied for both food and biological samples. 相似文献