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《应用化工》2016,(5):829-832
建立了2,5-二甲基呋喃(DMF)的气相色谱(GC)定量分析方法,跟踪测定DMF在低温下的氧化过程及动力学,用碘量法测定了DMF过氧化物的生成,并测定了DMF的氧化产物。结果表明,DMF与氧气在低温下的氧化呈现表观一级反应,温度为323.15,333.15,343.15,353.15,363.15 K时的反应速率常数分别为:0.004 6,0.006 4,0.008 9,0.011 8,0.015 0 h~(-1),反应表观活化能为29.08 k J/mol。在363.15 K反应10 h,主要氧化产物为5-甲基-2-呋喃甲醇(7.3%),反-3-己烯-2,5-二酮(70.8%),5-甲基-2-呋喃甲醛(13.4%),其他(8.5%)。 相似文献
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《应用化工》2022,(5):829-834
建立了2,5-二甲基呋喃(DMF)的气相色谱(GC)定量分析方法,跟踪测定DMF在低温下的氧化过程及动力学,用碘量法测定了DMF过氧化物的生成,并测定了DMF的氧化产物。结果表明,DMF与氧气在低温下的氧化呈现表观一级反应,温度为323.15,333.15,343.15,353.15,363.15 K时的反应速率常数分别为:0.004 6,0.006 4,0.008 9,0.011 8,0.015 0 h(-1),反应表观活化能为29.08 k J/mol。在363.15 K反应10 h,主要氧化产物为5-甲基-2-呋喃甲醇(7.3%),反-3-己烯-2,5-二酮(70.8%),5-甲基-2-呋喃甲醛(13.4%),其他(8.5%)。 相似文献
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以对二甲苯为原料,分别通过芳环上的溴代、亲核取代及α-位溴代3步反应,合成了2,5-二溴甲基对苯二甲腈。以碘作催化剂,对二甲苯与液溴在二氯甲烷中于12℃严格避光条件下搅拌反应18 h,得到2,5-二溴对二甲苯;2,5-二溴对二甲苯与氰化亚铜在DMF中加热回流48 h得到2,5-二甲基对苯二甲腈;2,5-二甲基对苯二甲腈与N-溴代丁二酰亚胺(NBS)在四氯化碳中被偶氮二异丁腈催化反应16 h得到2,5-二溴甲基对苯二甲腈,各步收率分别为96.3%、87.5%、31.4%。借助正交实验优化了各步的反应条件:溴代n(B r2)∶n(p-xylene)=2.2∶1,c(p-xylene)=3.2 mol/L,反应温度12℃,反应时间18 h;亲核取代n(CuCN)∶n(2,5-二溴对二甲苯)=2.5∶1,c(2,5-二溴对二甲苯)=0.2 mol/L,反应温度155℃,反应时间48 h;α-位溴代n(NBS)∶n(2,5-二氰基对二甲苯)=2.1∶1,c(2,5-二氰基对二甲苯)=0.1 mol/L,反应温度80℃,反应时间16 h。并对各步产品进行了质谱和核磁共振氢谱表征。 相似文献
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《化学工程》2017,(9):52-57
通过对二甲苯磺化、碱熔法合成2,5-二甲基苯酚,研究了影响磺化、碱熔产物收率和纯度的因素。磺化时酸性滤液回收套用,可减少三废,降低生产成本。最佳磺化条件:缓慢把硫酸往对二甲苯中滴加,硫酸与对二甲苯摩尔比为1.6∶1,反应温度125℃,反应时间2.0 h,2,5-二甲基苯磺酸钠收率为96.87%,纯度为99.30%。碱熔时,通入水蒸气、添加抗氧剂和硬脂酸钠,增加了物料的流动性,提高了收率和纯度。最佳碱熔条件:将KOH、NaOH、潮品钠盐、抗氧剂1035(2,2'-硫代双[3-(3,5-二叔丁基-4-羟基苯基)丙酸酯])和硬脂酸钠混合后投入反应釜,NaOH和KOH质量比3∶2,抗氧剂1035为4 g,硬脂酸钠为9 g,330—340℃保温2.0 h,2,5-二甲基苯酚收率为92.70%,纯度为99.45%。 相似文献
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利用对苯二酚、2-氯-5-硝基三氟甲苯合成得到1,4-双(2-三氟甲基-4-硝基苯氧基)苯,再在钯/炭、水合肼和有机溶剂的作用下,合成得到了1,4-双(2-三氟甲基-4-氨基苯氧基)苯,并对其性能进行了表征,包括其本身的熔点、红外吸收特征等。合成得到的1,4-双(2-三氟甲基-4-氨基苯氧基)苯与4,4'-二氨基二苯醚、2,2-双[4-(3,4-二羧基苯氧基)苯基]丙烷二酐反应,制得了含氟聚醚酰亚胺,并对其性能进行了表征。 相似文献
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以1,6-己二酸为起始物,合成得到噻吩-2,5-二甲酯,经醇化得到噻吩-2,5-二甲酸二甲酯,然后经过Claisen缩合反应得到了新型双(β-二酮)配体。并对它的合成条件分别进行了探索性实验,确定了合成它的各自优化条件。实验结果表明,在以THF为溶剂,噻吩-2,5-二甲酸二甲醇、2-乙酰基噻吩与金属钠的摩尔比为1:4.2:4.2的条件下,把溶解于THF中的2-乙酰基噻吩滴加到噻吩-2,5-二甲酸二甲酯的THF溶液中进行反应,控制反应温度40~45℃,产物双(β-二酮)配体的收率可达65.7%。产品通过元素分析、1HNMR、IR和MS进行组成和结构表征。 相似文献
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The objective of this work is to ascertain the characteristics of desirable (cure) and especially undesirable (scorch) crosslinking when carbon black filled ethylene propylene diene terpolymer (EPDM) is processed using different peroxide initiators. The mixing temperature and the nature of the peroxide initiator are crucial parameters affecting scorch (undesirably premature crosslinking) in this rubber. Processability and properties of EPDM prepared using various mixer set temperatures have been investigated. Dicumyl peroxide (Luperox DC), di(t‐butylperoxy) diisopropylbenzene (Luperox F), and 2,5‐dimethyl‐2,5‐di(t‐butylperoxy) hexane (Luperox 101) were used as crosslinking initiators. Higher mixing temperatures give shorter scorch times, greater scorch magnitudes, greater heterogeneities in crosslink spatial distribution and poorer tensile properties. However, extreme localization of the unwanted crosslinking at the rubber‐filler interface does have a beneficial effect. Luperox DC offers poorer processability and poorer resulting properties than do Luperox F and Luperox 101, due to its shorter half‐life and greater solubility in the rubber phase. This is the first time that the spatial heterogeneity of crosslinking and scorch has been related to the basic thermodynamics of 3‐component 2‐phase systems. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44523. 相似文献
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A two‐step investigation of polypropylene‐controlled degradation was performed. First the controlled degradation of polypropylene was investigated by assessing the effects of using dicumyl peroxide (DCP) and 2,5‐dimethyl‐2,5‐di(t‐butylperoxy) hexane (DHBP) in different suspensions (neat, calcium carbonate, and organically modified montmorillonite). The second part of this research was performed according to a factorial design at two levels (22 experimental design) with center point, in which peroxide concentration and reaction time were studied. Polypropylene degradation was assessed by melt flow rate (MFR) and parallel plate rheometry. Results showed that DCP presented higher molar efficiency in polypropylene degradation reactions in relation to DHBP; likely due to radical recombination reactions. The results also indicate that clay may catalyze the recombination reactions of polypropylene radicals. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013 相似文献
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2,5-二甲基-2,5-二叔丁基过氧化己烷对混炼型聚氨酯橡胶性能的影响 总被引:2,自引:0,他引:2
研究了2,5-二甲基-2,5-二叔丁基过氧化己烷(简称双-2,5)对混炼型聚氨酯橡胶的综合性能的影响,并与硫黄硫化的聚氨酯橡胶的性能进行比较。结果表明,添加过氧化物双-2,5的混炼型聚氨酯橡胶的硫化时间较短,扭矩值较高。与硫黄硫化体系相比,以双-2,5为硫化剂时,硫化胶的物理机械性能较低,但可以明显减少聚氨酯橡胶的高温压缩永久变形,且玻璃化温度较低。增加双-2,5的用量,硫化胶的耐油性能得到提高。 相似文献
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以摩尔比为2∶1的金属钠和异丁酸甲酯为原料,用石油醚(60~90℃)作溶剂,在反应过程中加入与金属钠等摩尔的三甲基氯硅烷作为易发生副反应中间体的捕获剂,在室温下反应5h合成了标题物。产率89.4%,比文献[2]产率提高14.4%。 相似文献
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以对二甲苯为原料,经三步化学反应合成聚(2,5-二甲基-1,4-亚苯基-1′,2′-乙二撑-1′-氯化二乙锍盐),讨论了温度、气氛和溶剂对聚合反应的影响。产品的结构由IR和1HNMR光谱得到确认 相似文献
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Free‐radical‐initiated grafting of maleic anhydride (MA) onto a polylactide (PLA) backbone was performed by reactive extrusion. A concentration of 2 wt % MA in the presence of 2,5‐dimethyl‐2,5‐di‐(tert‐butylperoxy)hexane (Lupersol 101) as the free‐radical initiator was used for all experiments. Two reaction temperatures were studied (180 and 200°C) with a peroxide initiator concentration between 0.0 and 0.5 wt %. Under these conditions, between 0.066 and 0.672 wt % MA was grafted onto the PLA chains. Triple‐detector size‐exclusion chromatography (TriSEC), melt flow index (MFI), and thermal gravimetric analysis (TGA) were used to characterize the maleated PLA polymers. Increasing the initiator concentration resulted in an increase in the grafting of MA, as well as a decrease in the molecular weight of the polymer. The maleation of PLA proved to be very efficient in promoting strong interfacial adhesion with corn native starch in composites as obtained by melt blending. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 477–485, 1999 相似文献
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选取了一条合理、成本相对低廉的合成2,5-二甲氧基苯乙胺新方法。在碱性条件下,对苯二酚经醚化得到1,4-二甲氧基苯,收率95.0%,再选用高选择性的溴化剂溴化后,收率90.0%,经格氏反应和羟乙基化反应制备2,5-二甲氧基苯乙醇,收率75.0%,醇与对甲苯磺酰氯反应得到酯,收率97.0%,最后经Gabriel反应可以制备相应的芳香乙胺化合物,收率70.0%。该路线反应较易,条件温和,对设备要求较低,原料价廉易得,适合工业生产。 相似文献