CoMn@NC催化5-羟甲基糠醛常压氧化为2, 5-呋喃二甲酸二甲酯

Dimethyl furan-2, 5-dicarboxylate (DMFDCA) is a valuable biomass-derived chemical that is an ideal alternative to fossil-derived terephthalic acid as a monomer for polymers. The one-step oxidation of 5-hydroxymethylfurfural (HMF) to DMFDCA is of practical significance. It not only shortens the reaction pathway but also avoids the separation process of intermediates; thus, reducing cost. In this work, non-noble bimetallic catalysts supported on N-doped porous carbon (CoMn@NC) were synthesized via a one-step co-pyrolysis procedure using different pyrolysis temperatures and proportions of metal precursors and additives. We employed the prepared CoMn@NC catalysts in the aerobic oxidation of HMF under mild reaction conditions to obtain DMFDCA. High-yield DMFDCA was obtained by screening the prepared catalysts and optimizing the reaction conditions, including the strength and amount of the base, as well as the reaction temperature. The optimized yield of DMFDCA was 85% over the Co₃Mn₂@NC-800 catalyst after 12 h at 50 ℃ using ambient-pressure oxygen. The physicochemical properties of the catalysts were determined using a variety of characterization techniques, the factors affecting the performance of each catalyst were investigated, and the relationship between the physicochemical properties and performance of the prepared catalysts was elucidated. A porous structure with a high surface area had a positive effect on mass transfer efficiency. Cobalt nanoparticles (NPs) and atomically dispersed Mn were coordinated to N-doped carbon to form M―N_x (where M = Co or Mn). Based on the Mott-Schottky effect, there was significant electron transfer between each metal and the N-doped carbon, additionally, the metal NPs supplied electrons to the carbon atoms. The electron-deficient metal site in the pyridinic N-rich carbon was beneficial for the activation of HMF and oxygen. The activation of oxygen produced reactive oxygen species (such as superoxide radical anions) to ensure high selectivity to DMFDCA through dehydrogenative oxidation of the hemiacetal intermediate and hydroxymethyl group of 5-hydroxymethyl-2-methyl-furoate. The existence of disordered and defective carbons increased the number of active sites. Subsequently, we performed a series of control experiments. Based on our current experimental results and previous studies, we propose a simple mechanism for the aerobic oxidation of HMF to DMFDCA. The catalyst was stable, its performance decreased slightly after two cycles, and it was tolerant to SCN⁻ ions and resistant against N or S poisoning. Furthermore, the use of this catalytic system can be expanded to various substituted aromatic alcohols, such as benzyl alcohols with different substituents, furfuryl alcohol, and heterocyclic alcohols. Simultaneously, the product type was further extended from methyl esters to ethyl esters with a high yield when the substrate reacted with ethanol. In conclusion, this catalytic system can be applied in the production of carboxylic esters for polymers.     

(S)-富马酸替诺福韦二吡呋酯的合成

以腺嘌呤为原料,经N-烷基化、O-烷基化、水解、酯化和成盐5步反应合成了(S)-富马酸替诺福韦二吡呋酯,总收率10.0%,其结构经1H NMR和ESI-MS确证。     

毛细管电泳非接触电导法测定4种中枢神经系统用药

运用毛细管电泳非接触式电导检测方法对4种中枢神经系统用药-盐酸阿扑吗啡、氢溴酸加兰他敏、富马酸喹硫平、氯氮平的分离进行了研究。考察了电泳介质的种类、浓度、分离电压、进样时间对分离效果的影响,在10 mmol/L三羟基氨基甲烷(Tris)-8 mmol/L柠檬酸(Cit)-20%甲醇的运行缓冲液中,激发电压为60V,激发频率为600kHz,4种药物在15 min内得到了分离。4种药物的线性范围分别为0.97～15.6 mg/L;0.97～15.6 mg/L;0.48～15.6 mg/L和0.97～250 mg/L,检测限为0.32,0.32,0.16和0.32 mg/L。     

高效液相色谱法测定食品中的富马酸二甲酯

采用高效液相色谱法测定食品中的富马酸二甲酯.样品中的富马酸二甲酯经甲醇提取后,以甲醇-乙酸铵溶液(体积比为55∶45)为流动相,C18色谱柱分离,二极管阵列检测器检测,检测波长为210 nm,外标法定量.方法的线性范围为1～16μg/mL(r=0.99987),检出限为0.1μg/g,测定结果的相对标准偏差为0.54%...     

气相色谱-质谱法测定富马酸二甲酯时内标物的选择

探讨了当采用气相色谱-质谱法测定富马酸二甲酯(DMFU)时内标物的选择问题。采用HP-5MS毛细管色谱柱,在50℃～300℃范围内程序升温分离及采用在50～400amu范围内全扫描方式和选择离子监测模式检测。试验结果表明:以丙二酸二甲酯(DMM)、丙二酸二乙酯(DEM)和戊二酸二甲酯(DMG)作为内标物,既能保持DMFU与3种内标物有良好的分离度,又能保持长久的稳定性,且3种内标物与DMFU的保留时间差均小于2.8min。DMFU的线性范围均为0.005～5.0mg·L~(-1)。方法用于实际样品中DMFU的测定,以上3种物质作为内标,所得结果无显著差别,因此DMM、DEM、DMG均可作为比较理想的内标物用于日常用品中DMFU的检测。     

气相色谱-质谱法测定家具及纺织品中富马酸酯类防腐剂

提出了气相色谱法测定家具和纺织品中富马酸二甲酯、富马酸二乙酯、富马酸单乙酯3种防腐剂。样品用乙酸乙酯超声提取后,30℃旋转蒸发器中浓缩至2 mL。用乙酸乙酯稀释定容至5.0 mL,通过DB-FFAP色谱柱分离,采用选择离子监测模式进行测定。富马酸二甲酯和富马酸二乙酯的的线性范围为0.05~5.00 mg.L-1、富马酸单乙酯的的线性范围为0.10~10.0 mg.L-1,测定下限(10S/N)依次为0.01,0.01,0.02 mg.kg-1。以家具和纺织品样品为基体,在3个浓度水平下进行回收试验,3种防腐剂的回收率均大于80%,相对标准偏差(n=6)均小于5.0%。     

石墨相氮化碳可见光下活化过一硫酸盐氧化降解光惰性邻苯二甲酸二甲酯的机理研究（英文）

近几年过一硫酸盐(PMS)活化技术备受关注,其中利用太阳能活化PMS具有可持续和环保的优势,但PMS本身不吸收可见光.因此,本文提出利用具有可见光响应的石墨相氮化碳(g-C3N4)激发产生光电子进而活化PMS.首先利用三聚氰胺前驱体通过热缩聚法制备g-C3N4,通过X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、紫外-可见光漫反射(UV-Vis)、荧光光谱(PL)、透射电镜(TEM)、N2吸附脱附测试(BET)、电化学等一系列方法对g-C3N4进行表征,研究其表面性质及光学性能.结果显示, g-C3N4具有典型的片层结构和可见光活性,禁带宽度为2.7 e V.本文选取光惰性的内分泌干扰物邻苯二甲酸二甲酯(DMP)为目标污染物,系统地研究了其降解动力学和降解机理.研究发现,在短波紫外光(254和300nm)照射下,直接光解和·OH参与的反应机理能实现DMP的光降解,而在可见光照射下g-C3N4介导的光催化过程不能使DMP分解;但当添加PMS时,体系主导自由基由·O2–转化为SO4·–和·OH,从而实现DMP的有效降解和矿化.研究还发现,高浓度的PMS和高剂量的g-C3N4均可以提高PMS的活化量和相应的DMP降解效率,但提高催化剂剂量的方式能更充分的利用PMS.尽管高浓度的DMP阻碍了PMS和光催化剂g-C3N4的有效接触,但可以提高PMS的利用率.当p H低于零电荷点(5.4)时, DMP的降解效率较高.此外,使用两种淬灭剂(乙醇和叔丁醇)与DMP进行竞争性实验,结合电子自旋共振检测,表明SO4·–和·OH都是体系主要的自由基.此外,还对g-C3N4的可持续性能进行考察,四次循环实验结果显示,该催化剂具有良好的可重复利用性.对DMP降解进行总有机碳测定,发现降低了19%.最后,利用液相色谱质谱联用对DMP降解产物进行定性定量分析,发现DMP主要通过SO4·–和·OH对苯环的攻击以及脂肪族链的氧化断键这两种途径进行降解.综上可见,利用可见光激发g-C3N4产生的光电子能有效活化PMS降解顽固型有机污染物,可为实现太阳能活化PMS技术提供有力的技术参考.     

富马酸丙酚替诺福韦合成工艺改进

对富马酸丙酚替诺福韦的合成工艺进行了改进,以干燥的替诺福韦为起始原料,与亚磷酸三苯酯反应得到(R)-9-(2-(苯基磷酰基甲氧基)丙基)腺嘌呤（3）; 3被氯化亚砜氯代得(R)-9-(2-(((苯基)(氯代)(磷酰基)甲氧基)丙基)腺嘌呤（4）; 4与L-丙氨酸异丙酯盐酸盐缩合得9-((R)-2-(((S)-((1-(异丙氧基羰基)乙基)氨基)苯氧基磷酰基)甲氧基)丙基)腺嘌呤（5）; 5经析晶纯化得9-((R)-2-(((S)-（((S)-1-(异丙氧基羰基)乙基)氨基)苯氧基磷酰基)甲氧基)丙基)腺嘌呤（丙酚替诺福韦,6）; 6与富马酸成盐得富马酸丙酚替诺福韦,其结构经¹H NMR, ¹³C NMR, MS(ESI),元素分析和XRD确证。按改进工艺进行公斤级规模放大,产品总收率达到32.2%,化学纯度99.92%,非对映异构体纯度99.99%。     

聚乙烯吡啶树脂对富马酸的吸附性能研究

通过静态吸附实验,研究了聚乙烯吡啶树脂(PVP)对富马酸的吸附性能。结果表明,该树脂对富马酸的吸附等温线同时满足Langmuir和Freundlich等温吸附方程;在无机盐存在下,与大孔强碱性树脂D204、弱碱树脂D308相比,PVP吸附富马酸的性能几乎不受无机盐的影响。D204树脂吸附富马酸是离子交换作用,D308树脂通过Lewis作用和静电作用吸附富马酸,而PVP树脂对富马酸的吸附行为是氢键所致,吸附为放热过程且能够自发进行。     

液相色谱法测定中药材中的富马酸单甲酯与富马酸二甲酯

建立了同时测定中药材中富马酸单甲酯(MMF)和富马酸二甲酯(DMF)的高效液相色谱方法。样品经乙酸乙酯提取、氨基复合石墨碳固相萃取柱净化后,C18柱分离,二极管阵列检测器检测。在0.025~5.0 μg/mL浓度范围内,色谱峰面积与分析物浓度呈良好线性关系,MMF和DMF的检出限(S/N=3)分别为0.015、0.020 mg/kg,定量下限(S/N=10)分别为0.05、0.06 mg/kg。当加标浓度水平为0.1、0.2、0.5 mg/kg时,MMF和DMF的回收率为78.9%~97.3%,相对标准偏差(RSD,n=6)为1.7%~6.0%。方法灵敏、可靠,能够满足中药材中MMF和DMF残留检测的要求。