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用DSC,FT-IR,~1H-NMR及索氏抽提等手段研究了聚碳酸酯(PC)/聚对苯二甲酸乙二醇酯(PET)共混体的酯交换反应。研究结果表明:PC/PET共混体在熔融处理过程中有酯交换反应发生,并有共聚产物形成,酯交换反应程度可用反应产物的FT-IR谱中特征基团的吸光度之比进行表征,酯交换反应程度不仅与熔融处理条件(反应时间、温度)有关,而且还与共混体的组成比相关。酯交换反应产物经索氏抽提后,抽提产物的FT-IR分析也证实了此结果。此外,利用抽提产物的~1H-NMR分析得出了酯交换反应中形成的共聚产物的结构式,并提出了可能的反应机理。 相似文献
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在有机胺的存在下,三苯基氯化锡与邻苯二甲酸反应,得到了五配位阴离子型有机锡羧酸酯化合物,通过IR、1H NMR、元素分析等技术手段对反应产物结构进行了表征,确定了反应产物的结构。 同时测定了反应产物对10种病菌的杀菌活性,结果表明,产物对芦笋茎枯、花生褐斑、水稻曲病菌和黄瓜黑星病菌的杀死率均为100%,对其它病菌具有中等强度的杀死率。 相似文献
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本文研究 了在非极性溶剂二氯甲烷中卤代苯和卤代萘用SO~3进行的磺化反应. 卤代苯最初开始磺化反应的产物是4-磺酸, 2-卤代萘的产物是8-磺酸. 当用过量的SO~3长时间反应时, 磺化反应得到三取代产物. 相似文献
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研究了在不同碱性条件下,对羟基苯甲醛与4-溴异戊烯的烷基化反应。通过调节反应条件可选择性地合成C-烷基化产物、O-烷基化产物或C-烷基化-O-烷基化产物。产物的结构经1H NMR,IR和MS表征。 相似文献
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Summary A CE method has been validated for the analysis of batches of lactose used as a pharmaceutical raw material. This method was
shown to be selective for lactose and was found to be quantitative. The separation was achieved due to on-capillary chelation
of the lactose with borate ion. The resulting complex was detected at 195nm. An internal standard is employed to improve injection
precision and detector linearity. A system peak occurred in the separation and was systematically investigated to show that
it was not sample related. The method was validated and successfully submitted to regulatory authorities and is now in routine
use in a number of our quality control laboratories. 相似文献
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利用原子吸收分光光度法分别用钾空心阴极灯测钠、锌空心阴极灯测铜,标准曲线线性良好,相关系数均在0.999以上。钾灯测量钠质控样结果为0.747 mg/L,在质控样标称值范围(0.712±0.049)mg/L之内。锌灯测量铜质控样结果为1.23 mg/L,在质控样标称值范围(1.19±0.05)mg/L之内。钾灯测钠的相对标准偏差为0.47%(n=6),加标回收率为99.8%。锌灯测铜的相对标准偏差为0.53%(n=6),加标回收率为103%。一灯多用在环境监测工作中是可行的。 相似文献
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建立了用硫酸分离-火试金重量法测定碲化铜中的金和银含量的方法。用硫酸溶解碲化铜样品,过滤,除去铜和碲,得到含金、银的沉淀物,沉淀物经灰化、配料、高温熔融制得铅扣。将铅扣灰吹,得到金银合粒,用硝酸溶解分离金,用重量法测定金含量。用金银合粒的质量扣除金粒的质量和分金液、洗液中杂质的质量即为银含量。采用灰皿、残渣熔融法补正,或用含碲、铜物料做基体加入纯金、纯银同试样方法测定,根据金、银的回收率加以补正,从而得到试样中的碲含量。实验结果表明,浓硫酸的加入量为30 mL,残余量应不少于15 mL。火试金中硅酸度为1左右,试样进炉温度以900℃为宜。该方法金、银测定结果的相对标准偏差分别为0.33%~1.97%,0.28%~1.27%(n=9)。金的回收率为98.5%~100.2%,银的回收率为95.5%~101.4%。该法满足生产控制检测和贸易结算的要求。 相似文献
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KBr催化剂上DMC与苯酚甲基化合成苯甲醚的反应机理研究 总被引:1,自引:0,他引:1
结合原位FT-IR,热力学分析及反应规律研究了KBr催化剂上碳酸二甲酯(DMC)氧位甲基化苯酚合成苯甲醚的反应机理。FT-IR显示KBr催化剂高于100℃活化苯酚生成酚盐,但至200℃也不活化DMC。共吸附的FT-IR及反应数据均显示苯甲醚高于150℃时生成。反应中检测到少量羰基甲氧基化产物苯基甲基碳酸酯(MPC)先于苯甲醚而生成,结合热力学计算及MPC分解转化的实验结果分析,生成MPC的反应是与生成苯甲醚的甲基化反应并行的可逆副反应。甲基化反应的机理为苯酚先被去质子化而形成酚盐,高于150℃时,酚盐的酚氧负离子亲核进攻DMC的甲基碳而生成苯甲醚。 相似文献
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Dawson型磷钨酸催化合成乳酸月桂醇酯 总被引:1,自引:0,他引:1
用Dawson型磷钨酸催化合成乳酸月桂醇酯。实验结果表明:Dawson型磷钨酸有较高的催化活性,反应时间短,酯收率高,工艺简单。最佳工艺条件为:醇/酸摩尔比为1.5:1,催化剂用量为0.3%,带水剂甲苯体积(mL)与反应物质量(g)之比为0.4:1~0.5:1,反应温度为115~140℃,反应时间30~50min。在此条件下,酯收率可超过93% 。 相似文献
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Sung Bae Kim Hyun Joo Kim Chang Joon Kim 《Applied biochemistry and biotechnology》2006,130(1-3):486-495
Methods of increasing the enzymatic digestibility of waste newspaper by adding Tween (TW)-20 and 80 surfactants were investigated.
Tween-series surfactants were selected because these surfactants increase cellulase activity during enzymatic hydrolysis and
do not inhibit cell growth in downstream fermentation processes. When surfactant was used in a pretreatment, a benefic effect
was expected in the enzymatic hydrolysis stage owing to surfactant carry-over from the pretreatment stage immediately upstream
of the hydrolysis. However, because it was necessary to wash the pretreated substrate with water to remove inhibitors produced
during pretreatment, no added benefit was obtained. When surfactant was used in the pretreatment only, it was found that it
had a marked effect on digestibility and that this effect was higher at lower enzyme loadings. Also, TW-80 was found to be
more effective than TW-20, and the addition of enzyme and TW-80 to substrate at the beginning of enzyme reaction was found
to most effectively increase digestibility. When TW-80 was added into either the pretreatment stage or the hydrolysis stage
the digestibilities of untreated sample increased by approx 40%, whereas an increase of only 45% was observed when TW-80 was
added to both stages. These results show that the addition of surfactant to either the pretreatment or the enzymatic hydrolysis
stage is sufficient to increase digestibility. 相似文献