响应面优化羧甲基醚化法制备马蹄抗性淀粉的工艺及理化性质研究

本实验以马蹄淀粉为原料通过羧甲基醚化法制取抗性淀粉,以羧甲基醚化马蹄抗性淀粉的得率为评价指标,通过单因素试验和Box-Behnken响应面试验优化其制备工艺,并对所得产品进行感官评价和理化指标分析。结果表明,羧甲基醚化法制备马蹄抗性淀粉的最优工艺参数为马蹄淀粉乳浓度12%,醚化剂用量120%,醚化温度43℃,该工艺下马蹄抗性淀粉得率为75.85%,与预测值76.02%接近,表明实验结果可靠。通过此方法可以便捷高效地生产出持水性强、颗粒较为完好、品质优良的马蹄抗性淀粉,为工业化生产提供了理论参考。

糖肟三甲基硅醚化衍生法分析中药多糖单糖组成研究

目的:建立糖肟三甲基硅醚化衍生法分析中药多糖单糖组成。方法:样品经糖肟三甲基硅醚化衍生,采用气相色谱法测定麻黄根多糖的单糖组成。色谱柱:DB-5毛细管柱(60 m×0.25 mm×0.25μm),载气:He,进样量:1μL,分流比20∶1,柱流速1.2 mL/min,程序升温,柱温150℃,以3℃/min至230℃,以20℃/min至300℃。质谱条件:EI(70 eV),离子源温度230℃,接口温度250℃,扫描范围:m/z 50~550,扫描率:2.5 scan/s。结果:9种单糖标准品均得到很好的分离。麻黄根纯化多糖Ⅱ中主要含阿拉伯糖、半乳糖和鼠李糖,其摩尔比为16.96∶5.03∶1.01,还有痕量的葡萄糖、岩藻糖和甘露糖。结论:该方法可以准确测定中药多糖中单糖的种类和比例,并成功用于检测麻黄根纯化多糖中的单糖组分。

聚乙二醇/醚化二羟甲基二羟基乙烯脲树脂整理涤纶织物的研究

对普通涤纶织物进行不同实验条件下的差别化亲水整理、测试、分析和比较,得出用聚乙二醇/醚化二羟甲基二羟基乙烯脲树脂混合整理液进行亲水整理后,织物的亲水性提高较大,且具有较好的耐洗性,其白度几乎不变,透气性与断裂强力稍有下降,织物手感稍微变硬。

醚化三羟甲基三聚氰胺树脂

三聚氰胺树脂是一种用途广，性能好的氨基榭脂，广泛用做织物树脂整理剂，交联剂．耐水剂。甲醚化羟甲基三聚氰胺树脂是经过长期实验研制的水溶性树脂，它与国内已投产的甲醚化六羟基三聚氰胺树脂相比，具有成本低，游离甲醛少、稳定性好等优点。

7-异丙基-4-甲基-1-甲醇的简单甲基化反应及其产物性质研究(英文)

研究了新化合物 7 异丙基 1 甲氧甲基 4 甲基 (1)的合成方法及其物理化学性质。通过 7 异丙基 4 甲基 1 甲醇 (2 )与甲醇之间的简单醚化反应即可以制得化合物 1,比常规醚化的反应条件温和而简单易行 ,仅用乙醚溶剂、无机酸催化剂和 0～ 5℃的反应温度 ,在数分钟内即可完成反应。反应还生成二聚体化合物 (5 )及其它少量多聚体副产物。经过1HNMR ,FTIR ,UV vis ,HR MS等波谱分析证实了新化合物 1和 5的化学结构。

高取代辛烯基琥珀酸酯酸解羧甲基田菁胶制备及性能研究

本文以田菁胶为原料,氯乙酸为醚化剂,辛烯基琥珀酸酐为酯化剂,吡啶为催化剂,以离子液体为溶剂,制备了高取代度辛烯基琥珀酸酯酸解羧甲基田菁胶,并对其性能及应用进行了研究。用酸碱滴定法测定羧甲基田菁胶的羧基含量,用皂化法测定辛烯基琥珀酸酯酸解羧甲基田菁胶的取代度。通过X射线衍射仪(XRD)研究了醚化、酸化和酯化对田菁胶结构影响,测定了改性田菁胶的冻融稳定性及接触角的性能影响。

低甲醛N-羟甲基三聚氰胺硬挺整理剂的合成

以多聚甲醛、三聚氰胺和醚化剂为主要原料，采用一步投料方法，制备了一种甲醛释放量低、稳定性好的醚化N-羟甲基三聚氰胺硬挺剂。通过评价产物稳定性和涤纶机织物经其整理后的硬挺度和甲醛释放量，优化了原料物质的量之比、反应pH值、反应温度和时间等，得到制备醚化N-羟甲基三聚氰胺硬挺剂的工艺条件：三聚氰胺、甲醛和醚化剂物质的量之比为1：7：8；N-羟甲基化pH值8-9，温度75℃，时间30min；醚化pH值5，温度70℃，时间40～50min。应用试验表明，整理品硬挺度可从1．8cm提高到5．0cm，甲醛释放量低于150mg／kg。

南海海洋红树林种子内生真菌2508号多糖G-22a的研究

从南海海洋红树林种子内生真菌 2 5 0 8号的菌体中提取到多糖G_2 2a ,通过酸水解及GC/MS研究表明 ,G_2 2a由鼠李糖、甘露糖和葡萄糖及少量的木糖、核糖醇组成。

Synthesis of Methyl Acetate by Dimethyl Ether Carbonylation over Cu/HMOR： Effect of Catalyst Preparation Method

Dimethyl ether carbonylation to methyl acetate was comparatively investigated over mor- denite supported copper （Cu/HMOR） catalysts prepared by different methods including evaporation, urea hydrolysis, incipient wetness impregnation and ion-exchange. The results showed that Cu/HMOR prepared via iron-exchange method exhibited the highest catalytic activity due to the synergistic effect of active-site metal and acidic molecular sieve support. Conversion of 95.3% and methyl acetate selectivity of 94.9% were achieved under conditions of 210℃, 1.5 MPa, and GSHV of 4883 h-1. The catalysts were characterized by nitrogen absorption, X-ray diffraction, NH3 temperature program desorption, and CO temperature program desorption techniques. It was found that Cu/HMOR prepared by ion-exchange method possessed high surface area, moderate strong acid centers, and CO adsorption centers, which improved catalytic performance for the reaction of CO insertion to dimethyl ether.

两种毛大丁草多糖 Gbp和 Gcp的组成研究

目的 从毛大丁草的根中分离提取多糖 ,测定其组成。方法 毛大丁草根的水提物经脱蛋白、脱色、乙醇沉淀得两种粗多糖 ,再经过 Sephadex G- 75和 Sephadex G- 5 0凝胶柱色谱纯化得到两种纯多糖 Gbp和 Gcp,用高效凝胶色谱 (HPGPC)测定 Gbp和 Gcp相对分子质量 ,通过完全酸水解后 ,进行三甲基硅醚化的 GC- MS分析 ,测定两种多糖的组成。结果 Gbp和 Gcp重均相对分子质量分别为 6 .6 5× 10 5和 7.4 5× 10 4 。 Gbp是由木糖、来苏糖、鼠李糖、核糖、葡萄糖和半乳糖组成 ,其比例约为 3∶ 3∶ 3∶ 2∶ 6∶ 2 ;Gcp主要由果糖组成 ,还有少量葡萄糖和木糖 ,其比例为 2 4∶ 4∶ 1。结论 通过凝胶柱色谱分析 ,所提取两种多糖 Gbp和 Gcp均为单一。

Effect of Calcination Temperature on Catalytic Activity and Textual Property of Cu/HMOR Catalysts in Dimethyl Ether Carbonylation Reaction

The effect of calcination temperature on the catalytic activity for the dimethyl ether （DME） carbonylation into methyl acetate （MA） was investigated over mordenite supported copper （Cu/HMOR） prepared by ion-exchange process. The results showed that the catalytic activity was obviously affected by the calcination temperature. The maximal DME conversion of 97.2% and the MA selectivity of 97.9% were obtained over the Cu/HMOR calcined at 430 ℃ under conditions of 210 ℃, 1.5 MPa, and GSHV of 4883 h^-1. The obtained Cu/HMOR catalysts were characterized by powder X-ray diffraction, N2 absorption, NH3 temperature program desorption, CO temperature program desorption, and Raman techniques. Proper calcination temperature was effective to promote copper ions migration and diffusion, and led the support HMOR to possess more acid activity sites, which exhibited the complete decomposing of copper nitrate, large surface area and optimum micropore structure, more amount of CO adsorption site and proper amount of weak acid centers.

Synthesis of anisole by vapor phase methylation of phenol with methanol over catalysts supported on activated alumina

The synthesis of anisole by vapor phase methylation of phenol with methanol over activated alumina（AA） supported catalysts was investigated in a fixed bed reactor. KH2PO4/AA gave the best performance among the eight tested catalysts. The catalyst was prepared by loading KH2PO4 on AA and then calcining at the optimized temperature of 700 °C for 8 h. In the vapor phase reaction, the level of anisole yield（LAY） has a maximum at 400–450 °C when the temperature varied from 300 to 500°C, which decreased slightly with increasing WHSV and increased distinctly with increasing mole fraction of methanol. On comparing O‐methylation and C‐methylation of phenol, a low temperature,high WHSV（short residence time）, and a low methanol concentration over the KH2PO4/AA catalyst with higher K contents were found to increase anisole selectivity by O‐methylation of phenol. The reaction routes to the major products and the catalytic mechanism were suggested, and a ‘K‐acid＇bifunctional process may be a critical factor to the formation of anisole.

基于Aspen Plus的制备高纯度异丁烯全流程模拟

根据中石油某炼厂要求,采用炼厂混合碳四馏分为原料,以该厂生产装置为基础数据,基于Aspen Plus软件模拟工艺流程,对碳四分离-异丁烷脱氢-MTBE醚化-MTBE裂解全工艺流程进行模拟。本工艺旨在合理利用炼厂碳四资源,满足市场对高纯度异丁烯的需求,开发碳四资源的化工利用。

织物后整理剂醚化六羟甲基三聚氰胺树脂的研究

三聚氰胺和甲醛经羟甲基化、醚化反应,生成甲醚化六羟甲基三聚氰胺树脂。本文探讨该织物后整理剂的制备工艺和条件,试验结果显示:其最佳条件为反应温度80℃、反应时间5h,pH值为7.5～8.0,催化剂为NaOH-乌洛托品,甲醛辅集剂为氨基脲。实验制得产品中游离甲醛含量(2%、干物质含量为40～45%,产品水溶性好,储存稳定性好,为工业化生产提供了依据。

Modifying the acidity of H-MOR and its catalytic carbonylation of dimethyl ether

Among the reactions catalyzed by zeolites there are some that exhibit high selectivity due to the spatial confinement effect of the zeolite framework.Tailoring the acidity,particularly the distribution and location of the Bronsted acid sites in the zeolite is effective for making it a better catalyst for these reactions.We prepared a series of H-mordenite（H-MOR） samples by varying the composition of the sol-gel,using different structure directing agents and post-treatment.NH3-TPD and IR characterization of adsorbed pyridine were employed to determine the amount of Bronsted acid sites in the 8-membered ring and 12-membered ring channels.It was shown that controlled synthesis was a promising approach to improve the concentration of Bronsted acid sites in MOR,even with a low Al content.Using an appropriate composition of Si and Al in the sol-gel favored a higher proportion of Bronsted acid sites in the 8-membered ring channels.HMI as a structure-direct agent gave an obvious enrichment of Bronsted acid sites in the 8-membered ring.Carbonylation of dimethyl ether was used as a probe reaction to examine the modification of the acid properties,especially the Bronsted acid sites in the 8-membered ring channels.There was a linear relationship between methyl acetate formation and the number of Bronsted acid sites in the 8-membered ring channels,demonstrating the successful modification of acid properties.Our results provide information for the rational design and modification of zeolites with spatial constraints.

Spacial hindrance induced recovery of over-poisoned active acid sites in pyridine-modified H-mordenite for dimethyl ether carbonylation

Zeolite catalysts,such as H-mordenite(H-MOR),are readily deactivated by coke deposition in carbonylation reactions.Pyridine modification of H-MOR can improve its stability but can lead to an undesirable loss in catalytic activity.Herein,we report the intrinsic impact of the pyridine adsorption behavior on H-MOR and the spacial hindrance of the zeolite frameworks on dimethyl ether(DME)carbonylation at a molecular level.We discovered that acid sites at O2 positions,located on common walls of eight-membered ring(8-MR)side pockets and 12-MR channels,were active in DME carbonylation,but were unfortunately poisoned during pyridine modification.Density functional theory calculations revealed that the pyridine-poisoned acid sites at the O2 positions could be easily regenerated due to the spacial hindrance of the zeolite frameworks.Accordingly,they can be facilely regenerated by proper thermal treatment,which induces 60%promotion in the catalytic activity along with a high stability.Our findings demonstrate the determining role of O2 positions in H-MOR for DME carbonylation and provide a new avenue for the rational design of other efficient zeolite-relevant catalytic systems.

Organic‐free synthesis of MOR nanoassemblies with excellent DME carbonylation performance

Seed‐assisted low alkalinity gel system was developed to explore the organic‐free synthesis of MORzeolite.MOR nanoassemblies with Si/Al ratio(SAR)up to 9.4 and high solid yield(84–94%)weresuccessfully obtained under controlled low alkalinity conditions.Characterization results demonstratethat the acid strength increases in parallel with the SAR,while the total acid amount and theproton distribution in the main channels and the side pockets are similar for the samples.The protondistribution in the H‐MOR is not straightforwardly related to the Na+distribution in theas‐synthesized MOR,implying the transfer of the protons among the oxygen sites of framework Tatom.Relative to low‐silica samples I‐5.3 and I‐7.4,sample I‐9.4 displays the best mass transferperformance and accessibility of the acid sites by pyridine due to its relatively low Al density andmild dealumination degree.Correspondingly,sample I‐9.4(pyridine‐modified catalyst)shows thebest activity with ca.100%selectivity of methyl acetate(MAc)in the DME carbonylation reaction.The high steady MAc yield(6.8 mmol/g/h)over sample I‐9.4 suggests the promising application ofMOR nanoassemblies synthesized by this economical organic‐free strategy.

Synthesis of 9,9′-Bis(methoxymethyl)fluorene

This paper describes the procedures for the facile synthesis of 9,9′-bis(methoxymethyl)fluorene using fluorene as starting material. By hydroxymethylation and etherification reaction, the fluorene can be converted to desired products with high yield and purity. The optimum conditions of the synthetic procedures were determined. For hydroxymethylation, the reaction temperature was 13 ℃and the mole ratio of sodium methoxide to paraformaldehyde was 0.26; and for etherification, the reaction temperature was 40 ℃and the reaction time was 15 h. Under the optimum conditions, an overall yield of 580 0 and purity of 99.20 0 were obtained.

Constrained Al sites in FER-type zeolites

Crystallographic sites of Brönsted acids(Si-OH-Al)in zeolites,which are closely associated with the Al sites,play a significant and unique role in the catalytic application,especially when they are distributed in open channel systems or confined in cavities with small pore openings.In this article,we unraveled constrained Al crystallographic sites in FER-type zeolites containing the distinct local environments(10-ring channels and ferrierite cavities)by Rietveld refinement against the powder X-ray diffraction data.Final refinement demonstrates that regardless of the types of structure-directing agents and synthetic medium utilized,T1 and/or T3 are Al-rich positions,which are further confirmed by theoretical calculations.This new finding of constrained Al sites in the FER-type zeolite can well explain its limited catalytic activity in the DME carbonylation reaction.

14-3-3 proteins—an update

14-3-3 is a highly conserved acidic protein family, composed of seven isoforms in mammals. 14-3-3 protein caninteract with over 200 target proteins by phosphoserine-dependent and phosphoserine-independent manners. Little isknown about the consequences of these interactions, and thus are the subjects of ongoing studies. 14-3-3 controls cellcycle, cell growth, differentiation, survival, apoptosis, migration and spreading. Recent studies have revealed newmechanisms and new functions of 14-3-3, giving us more insights on this fascinating and complex family of proteins.Of all the seven isoforms, 14-3-3σ seems to be directly involved in human cancer. 14-3-3σ itself is subject to regulationby p53 upon DNA damage and by epigenetic deregulation. Gene silencing of 14-3-3σ by CpG methylation has beenfound in many human cancer types. This suggests that therapy-targeting 14-3-3σ may be beneficial for future cancertreatment.