二甲基甲酰胺的生产

二甲基甲酰胺是性能优良的溶剂和化工原料，尤其是高纯二甲基甲酰胺在聚氨酯合成革、聚丙烯腈纤维生产中有独特的用途。本文介绍二甲基甲酰胺的生产方法和国内外生产情况。     

DMF生产系统技改总结

N,N-二甲基甲酰胺(DMF)是一种优良的有机溶剂及浆料行业的重要原料。通过十几年的发展,国内DMF生产能力大幅提升,市场竞争日趋激烈。为应对激烈的市场竞争,在DMF生产中对原料、工艺和设备等方面作了大量的技术改造,确保装置稳定运行,并降低了生产成本。     

火绒草提取物抗氧化活性的研究

测定火绒草水提物和醇提物中多酚及总黄酮含量,证实水提物和醇提物中含有以黄酮类为主要成分的多酚类物质。通过测定火绒草提取物的总还原力,超氧阴离子自由基(O2·)、羟自由基(·OH)清除能力、脂质过氧化抑制作用、清除亚硝酸盐自由基和亚硝胺阻断率,表明火绒草水提物和醇提物具有较强的还原性和清除·OH 和O2·的活性,且醇提物的作用比水提物更有效;对脂质过氧化的抑制率达到60% 以上。火绒草提取物具有较强的清除亚硝酸钠和阻断亚硝胺合成的能力,水提物对亚硝酸盐最大清除率为77.7%,醇提物对亚硝胺合成的阻断率98.0%。     

PDMAEMA/PSF中空纤维外压纳滤膜对无机盐的截留性能研究

主要研究聚甲基丙烯酸N,N-二甲氨基乙酯（PDMAEMA）/聚砜（PSF）中空纤维外压纳滤膜对不同种类无机盐的截留性能,并研究了无机盐溶液的浓度、运行压力、溶液温度、pH对截留性能的影响.实验表明：PD-MAEMA/PSF中空纤维纳滤膜荷正电,对离子的截留有选择性,对阳离子的截留顺序为：Mg^2＋＞Na^＋＞K^＋,对阴离子的截留顺序为：Cl^-＞Br^-＞I^-.随着盐溶液浓度的增加,截留率和通量均下降,所制备的纳滤膜对无机盐的截留表现出对温度、pH的敏感性.     

Poly(isatin-piperidinium-terphenyl) anion exchange membranes with improved performance for direct borohydride fuel cells

In this work, an effective design strategy for anion exchange membranes (AEMs) incorporating ether-bond free and piperidinium cationic groups promote chemical stability. A series of poly (isatin-piperidium-terphenyl) based AEMs were synthesized by superacid catalyzed polymerization reaction, followed by quaternization. The effect of functionalization on the performance of poly (isatin-N-dimethyl piperidinium triphenyl) (PIDPT-x) AEMs was investigated. Highly reactive N-propargylisatin was introduced into the backbone to achieve high molecular weight polymers (η_a = 2.06–3.02 dL g⁻¹) leading to robust mechanical properties, as well as modulating 1.78–2.00 mmol g⁻¹ of the ion exchange capacity (IEC) of the AEMs by feeding. Apart from that, the rigid non-ionized isatin-terphenyl segment provides AEMs improved dimensional stability with a swelling ratio of less than 12% at 80 °C. Among them, PIDPT-90 exhibited a higher OH⁻ conductivity of 105.6 mS cm⁻¹ at 80 °C. The alkali-stabilized PIDPT-85 AEM was presented, in which OH⁻ conductivity retention maintained 85.6% in a 2 M NaOH at 80 °C after 1632 h. Afterward, the direct borohydride fuel cells (DBFC) with PIDPT-90 membrane as a separator showed an open-circuit voltage of 1.63 V and a peak power density of 75.5 mWcm⁻² at 20 °C. This work demonstrates the potential of poly (isatin- N-dimethyl piperidinium triphenyl) as AEM for fuel cells.     

Nitrosamines Extraction from Frankfurter Sausages by using Superheated Water

An efficient, rapid, and inexpensive method for extraction and clean-up of some selected volatile nitrosamines from frankfurter sausages was developed by using superheated water coupled with solid-phase extraction. Because a coextraction of lipid caused a serious problem during the extraction, a subsequent clean-up step using fat-selective Florisil adsorbent with 60% diethyl ether-dichloromethane was then necessary. Various factors affecting superheated water extraction, such as flow rate, extraction temperature, dynamic time, and static time were optimized by using a full factorial design with three replicates. The optimal extraction temperature was 140°C with dynamic and static time of 10 and 5 min, respectively, and a flow rate of 1.0 mL/min. Separation and quantification of nitrosamines were carried out using GC-FID and GC-MS in selected ion monitoring mode. Direct application of this method to frankfurter samples allowed overall recoveries of N-nitrosamines in the range of 81-106% with < 10% RSD, and the detection limit of the coupling method ranged between 0.47-1.48 ng nitrosamines injected.     

萃取分离低浓度DMF含盐废水的液-液平衡

 利用液-液平衡釜测定了在常压下,温度为293.15K,Na₂SO₄质量分数分别为0、1%、3%、5%、7%条件下的N,N-二甲基甲酰胺(DMF)-水-氯仿体系的液-液平衡数据。实验结果表明,随着盐浓度的增加,DMF的选择性系数增大。采用NRTL活度系数模型对实验数据进行了热力学关联,回归得到该体系的二元交互性参数,并得到了模型参数随盐浓度变化的规律。运用回归得到的模型参数对该体系的液-液相平衡数据进行了预测,计算值与实验值的相对均方根误差在7.15%以内,绝对平均误差在1.46%以内,说明NRTL模型能较好地预测该体系的液-液平衡关系,可为萃取分离低浓度DMF含盐废水提供了工艺设计和模拟优化的基础数据。     

不同酯化度的酯基季铵盐阳离子表面活性剂的制备及性能

实验以十二烷基二甲基叔胺(NDT)与环氧氯丙烷(ECH)为原料,合成中间体(2,3-环氧丙基)十二烷基二甲基氯化铵。经正交实验确定的最佳合成条件为:以丙酮为溶剂,反应时间4 h,反应温度30℃,n(NDT):n(ECH)=1:1;再与长链饱和烷基脂肪酸反应,合成不同酯化度的酯基季铵盐阳离子表面活性剂(Ⅰ、Ⅱ)。降解实验结果表明,酯基季铵盐阳离子表面活性剂(Ⅰ、Ⅱ)降解性能优异,降解性随着疏水链的增长而减小,属易生物降解的阳离子表面活性剂。     

槲皮素-聚乙二醇固体分散体对亚硝化反应的抑制作用

以槐米为原料制备槲皮素。为改善槲皮素的水溶性,以聚乙二醇为载体,采用熔融法将其制成槲皮素-聚乙二醇固体分散体,使其在水中的溶解度由11．8mg／L提高到80．2mg／L。在模拟人体胃液的条件下,考察该分散体对亚硝化反应的抑制作用。结果表明,槲皮素-聚乙二醇固体分散体对亚硝化反应具有较强的抑制作用,其对亚硝胺合成的最大阻断率达91.3％,对亚硝酸钠的最大清除率为86．1％。