木质素磺酸镁接枝丙烯酰胺的影响因素

天然高分子化合物木质素是木材水解工业和造纸工业的副产物。早期人们在研究纤维素同甲基丙烯酸甲酯、丙烯腈的接枝反应中时发现了木质素的接枝反应活性[1],Meisterh和Patil[2]则实现了将—CONH2接枝于木质素的设想,雷中方[3]等研究了木质素同具有较好吸附能力的—CONH2的接枝改性,并讨论了改性产物的水处理性能,他们所用的木质素是采用酸析法从碱法草浆黑液中提取的。本文以酸法制浆的红液 木素磺酸镁为原料,合成了木质素 丙烯酸胺接枝共聚物,并对接枝聚合过程中的引发体系、引发剂浓度、反应温度、木素与单体用量比、固液比等影…     

醇水介质中漆酶催化氧化漆酚及其类似物

本文作者在醇水介质中对漆酚及其类似物的酶催化氧化反应进行了研究。探讨了混合溶剂中漆酶的行为。结果发现邻苯二酚被烷基取代后更有利于漆酶的催化氧化。反应可能经过两个步骤,先是底物氧化生成黄色苯醌类物质,然后醌类中间物偶联形成多聚酚。     

酶解木质素/Mg（OH）2复合材料的合成及阻燃性能研究

以酶解木质素、NaOH和MgSO4·7H2O为原料,制备酶解木质素包覆Mg（OH）2复合材料。通过红外光谱（FT-IR）、热重（TGA-DTA）及透射电镜（TEM）分析对复合材料进行结构表征及包覆形貌观察,结果表明,酶解木质素成功包覆Mg（OH）2,该复合材料在800℃残炭量可达46．24％。研究了复合材料与微胶囊红磷互配添加入丁苯橡胶的阻燃性能,垂直燃烧测试结果表明,当复合材料添加量达到100％时,阻燃级别可达到FV-0级。共混硫化胶燃烧残渣的SEM照片表明,燃烧后胶料的成炭效果很好,炭层连续致密,孔洞很少。     

半导体硅上电沉积Ni-Pd-P薄膜及其结构

采用控电位的沉积方式在半导体硅上制备出ＮｉＰｄＰ薄膜,结果表明镀液中Ｈ３ＰＯ３含量的增加对Ｐ、Ｎｉ的析出有促进作用,对Ｐｄ的析出有抑制作用．随ｐＨ值的升高,镍含量不断升高,Ｐｄ、Ｐ含量不断下降．Ｐ含量对薄膜内应力有很大影响,含Ｐ质量分数为１４９％的ＮｉＰｄＰ镀层表面上有许多裂缝,当Ｐ含量增加到２６１％时,镀层表面的裂缝已基本消失,继续增加Ｐ含量到３５０％时,裂缝完全消失．ＮｉＰｄＰ镀层的结构与其组成密切相关,Ｐ含量小于２００％的ＮｉＰｄＰ镀层形成的是面心立方结构的固溶体．Ｐ含量大于４００％的薄膜为非晶态结构．     

丙烷在负载型V2O5/Zr3(PO4)4催化剂上的氧化脱氢

制备了无定型的磷酸锆Ｚｒ３（ＰＯ４）４载体,采用浸渍法在载体上负载０６％～６０％的Ｖ２Ｏ５．所制备的催化剂在丙烷氧化脱氢反应中具有较好的催化性能,如３０％Ｖ２Ｏ５／Ｚｒ３（ＰＯ４）４催化剂在丙烷转化率为１７０％时,丙烯选择性可达５３８％,丙烯收率达９１％．考察了不同反应条件下催化剂的性能．ＸＲＤ、ＩＲ和Ｒａｍａｎ光谱表明,Ｖ２Ｏ５在Ｚｒ３（ＰＯ４）４载体上主要是以高度分散的钒氧物种存在;ＥＳＲ分析结果证明催化剂中存在Ｖ４＋物种,表明Ｖ５＋／Ｖ４＋参与了氧化还原反应．     

不同提纯方法对竹木质素结构特性的影响分析

应用UV、FT-IR、GPC和GC-MS研究了不同制备方法提纯的慈竹磨木木质素(milledwoodlignin,MWL)的结构特性,结果表明慈竹木质素属于愈疮木醇-芥子醇-对香豆醇(GSH)型木质素,竹木质素侧链含有少量的α-β碳碳双键,慈竹中含有数量相当多的紫丁香基结构单元,且紫丁香基结构单元的含量高于愈疮木基结构单元的含量;慈竹木质素含有酯键,主要是对-香豆酸的羧基与酚羟基发生酯化反应生成的.经超声波辅助碱抽提的木质素相对分子质量分布比较均匀,乙醇抽提可以增加木质素的重均分子质量.慈竹木质素的紫丁香基单元(S-unit)存在大量的β-O-4的联接,竹木质素中松柏醇和松柏醛以及香豆醛和香豆酸的含量很少,木质素H单元的侧链γ-碳存在少量醚键联接,愈疮木基单元(G-unit)和S单元的侧链γ-碳不存在醚键联接.     

口服聚酯聚醚疫苗蛋白微球的制备研究

采用本体聚合法合成不同聚醚含量的聚酯聚醚嵌段共聚物聚 ＤＬ 乳酸 聚乙二醇（Ｐｏｌｙ ＤＬ ｌａｃｔｉｄｅ ｂ ｐｏｌｙｅｔｈｙｌｅｎｅｇｌｙｃｏｌ,ＰＥＬＡ）．ＰＥＬＡ及ＰＬＡ包裹人血清白蛋白（ＨＳＡ）微球采用溶剂挥发法双乳液体系（Ｗ１／Ｏ／Ｗ２）制备．微球球形规整,粒径集中在０５～５０μｍ．用ＣＢＢ法检测微球中蛋白含量,蛋白包裹量达２５％,包裹效率近８０％．从双乳液体系中界面张力角度考察了聚合物囊材的性质、稳定剂的种类及Ｗ１／Ｏ的稳定性等对微球粒径及蛋白包裹量的影响．微球体外释放结果表明ＰＥＬＡ蛋白微球的突释现象不明显,释放速度较为恒定．     

木质素阳离子絮凝剂的合成及其絮凝性能研究

以酶解木质素、甲醛、二甲胺及阳离子化试剂为原料,制备了木质素基阳离子絮凝剂.改变阳离子化试剂的用量、缩合反应的温度和时间等因素,制备不同阳离子度的木质素阳离子絮凝剂;通过其对酸性黑10B的脱色效果研究,确定了最优的制备方案.利用最优条件制备的木质素阳离子絮凝剂对三种不同种类阴离子染料废水进行了絮凝脱色处理.结果表明,原...     

微乳液中脂肪酶和含明胶的微乳液凝胶中固定化脂肪酶的催化特性

在双2－乙基己基琥珀酸酸酯碘酸钠（AOT）油包水微乳液中Calytical脂肪酶催化月桂酸和戊醇的酯化反应动力学研究表明,反应符合乒乓（Bi,Bi)机制,表观速率常数km酸＝0．13518mol/L,km醇＝0.22423mol/L,最大反应速率vmax=1.3873*10^-5mol/(L.min.mg)。将该脂肪酶固定于含明胶的微乳液凝胶（MBGs)中,制得固定化脂肪酶,含酶MBGs在非极性溶剂中可作为固相催化剂,并研究了其在辛烷中催化酯化的性能。所制得的含酶MBGs物理稳定性好,重复利用10次以上,其转化率仍达初始转化率的90％。     

质谱、红外和核磁研究木质素模型物在Co-salen仿酶体系中的降解反应

根据GC-MS、FT-IR和13C-NMR对降解产物与结构变化的分析,可得出紫丁香基木质素模型物在Co-salen仿酶反应体系中的降解机理.质谱、红外光谱和核磁检测结果表明,反应过程中,木质素模型物β-O-4、Cα-Ar、Cα-Cβ连接断裂,苯环开环,同时发生酚羟基醚化和甲氧基脱甲基反应,产生4-羟基-3,5-二甲氧基苯乙酮、4-羟基-3,5-二甲氧基苯甲醛、4-羟基-3,5-二甲氧基苯甲酸、3-羟基-4,5-二甲氧基苯甲酸.     

N,N′-二(芳磺酰)亚磺酰胺-S-(2-苯并咪唑基)类化合物的合成

本文报道了新化合物N,N＇—二(芳磺酰)亚磺酰胺—S—(2—苯并咪唑基)钠(a～e)以及N,N＇—二(芳磺酰)亚磺酰胺—S—(2—苯并咪唑基)(f～i)的合成。通过在感光乳剂中的应用,我们发现a,b和c具有超增感作用,它们分别使卤化银乳剂的感光度提高62％,22％和45％。 钠—N—氯芳磺酰亚胺化合物既是一类精细化工产品,又是一类重要的反应中间体。由它们     

Phosphorylation of trivalent metal tris(3-bromo-2,4-pentanedionates)

Reactions of chromium(III) and cobalt (III) tris(3-bromo-2,4-pentandionates) with sodium dibutyl phosphate, sodium dibutylphosphinate, sodium dibutyl dithiophosphate, and sodium dibutyldithiophosphinate were studied. Oxygen-containing derivatives of phosphorus acids give metal polyphosphates and polyphosphonates, and in the case of sodium dibutyl phosphate, a bromine substitution product was isolated in 3% yield. The reactions of the chelates with sodium dibutyl dithiophosphate and sodium dibutyldithiophosphinate, substitution products were isolated in 54% and 65% yields, respectively. The reactions all involved reductive dehalogenation along with substitution.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 9, 2004, pp. 1472–1475.Original Russian Text Copyright © 2004 by Shapkin, Apanasenko, Skobun, Ivanova.This revised version was published online in April 2005 with a corrected cover date.     

HPLC法测定鸡精中谷氨酸钠的含量

以邻苯二甲醛与谷氨酸钠中的氨基进行柱前在线衍生化反应,采用C18色谱柱分离、荧光检测器（激发340nm,发射450nm）进行测定,建立了柱前衍生反相高效液相色谱测定鸡精中谷氨酸钠含量的方法。该方法相对标准偏差为0．69％,加标回收率为99．1％～101％,在0．10~50．0mg／L范围内,谷氨酸钠的峰面积和浓度之间的相关系数为0．9999,保留时间和峰面积的相对标准偏差分别为1．22％和0．71％,鸡精中谷氨酸钠定量下限为0．2μg／g。     

SO_2和H_2O(g)对新疆高钠煤中钠挥发和形态迁移的研究

在水平管式炉上进行了400-1 100℃新疆高钠煤恒温燃烧实验,并利用逐级提取的方法分析煤及煤灰中钠的赋存形态,研究煤中钠的释放和形态迁移特性。重点考察700和1100℃下H_2O(g)和SO_2(g)单因素及双因素对煤中无机钠挥发和形态迁移的影响。结果表明,随着温度的升高,煤中钠的释放比例逐渐增大,其中,有机态钠最先析出,其次是水溶态无机钠,硅铝酸盐形式的无机钠则由于高热稳定性不易分解或挥发。低温下(700℃)H_2O(g)的存在降低了钠的挥发,而较高温度下(1 100℃)焦炭与水蒸气反应生成的局部还原性气氛促进煤中钠的挥发,但当入口气氛中H_2O(g)浓度高于20%时,促进作用减小。SO_2的存在抑制了煤中钠的挥发,随着燃烧温度升高,SO_2对钠的抑制作用减弱。H_2O和SO_2双因素作用下,低温下(700℃)抑制了煤中钠的挥发,而较高温度下(1 100℃)钠的挥发特性取决于两者在入口气氛中的浓度。对于选取的高钠煤,20%H2O和2.0×10-3SO_2入口气氛下,1 100℃煤燃烧钠的挥发比例由86%提高到了87.1%。     

二氧化碳和水气氛对高钠煤转化过程中钠迁移的影响

对新疆的两种高钠煤（伊犁煤YL、呼图壁煤HTB）进行了N₂、CO₂和H₂O气氛和不同温度下钠迁移的研究。采用逐级萃取和湿法消解法确定了原煤、半焦中钠的赋存形态,定量研究了两种煤中钠的挥发及迁移规律。结果表明,YL煤的形态钠中水溶钠占80.08%,HTB煤的形态钠中不溶钠占61.54%。不同气氛下,升高温度都可促进两种煤中钠的挥发,半焦中水溶钠比例减小,醋酸铵可溶钠比例会出现先增加后减少现象,盐酸可溶钠比例呈增加趋势。对于YL煤,CO₂气氛可抑制钠的挥发,H₂O蒸气可促进钠的挥发;900℃时,YL煤CO₂气氛下钠挥发仅为N₂气氛下的50.25%,而H₂O气氛钠挥发为N₂气氛下的111.45%。对于HTB煤,CO₂气氛也可抑制钠的挥发,900℃时CO₂气氛下钠挥发为N₂气氛的80.91%;HTB煤在H₂O蒸气下,800℃之前钠挥发高于N₂,当900℃时,钠挥发略低于N₂气氛。YL煤形态钠中以水溶钠为主,其挥发的同时会向盐酸可溶钠及不溶钠转变。而HTB煤形态钠中以不溶钠为主,其次是水溶钠,CO₂和H₂O气氛能促进不溶钠向其他可溶态钠转变。     

高效液相色谱法同时测定食品中丙酸钙(钠)和双乙酸钠

建立高效液相色谱法同时测定食品中的丙酸钙(钠)和双乙酸钠。采用Acclaim120 C_(18)色谱柱(150mm×4.6 mm,5μm),以1.5 g/L磷酸氢二铵溶液(用1 mol/L磷酸溶液调pH至2.7~3.5)–甲醇混合液(体积比为95∶5)作为流动相,流量为1.0 mL/min,在214 nm波长下检测。丙酸与双乙酸钠的质量浓度在0.05~0.5 mg/mL范围内线性关系良好,相关系数均大于0.999。丙酸和双乙酸钠的加标回收率分别为95.58%~98.95%,96.12%~99.25%,测定结果的相对标准偏差分别为1.50%,1.41%(n=6)。该法适用于糕点及调味品中丙酸钙(钠)和双乙酸钠含量的检测。     

Liquid chromatographic determination of multiple sulfonamides, nitrofurans, and chloramphenicol residues in pasteurized milk

A rapid and selective liquid chromatographic method was developed to detect 6 sulfonamides, 3 nitrofurans, and chloramphenicol residues in pasteurized milk. The 10 drugs were extracted with chloroform-acetone and the organic phase was evaporated; the residues were dissolved in an aqueous sodium acetate buffer solution 0.02M (pH = 4.8), and the fat was removed by washing with hexane. The aqueous layer was collected, filtered, and injected. The 6 sulfonamides and chloramphenicol were detected at 275 nm ultraviolet (UV) using a gradient system starting with sodium acetate buffer solution-acetonitrile (95 + 5) and finishing with sodium acetate buffer solution-acetonitrile (80 + 20). Nitrofurans were detected at 375 nm (UV) isocratically with sodium acetate buffer solution-acetonitrile (80 + 20). For 50 ppb fortified milk, the average recoveries were (sulfathiazole) 65.52%; (sulfamerazine) 75.36%; (sulfamethazine) 93.94%; (sulfachlorpyridazine) 75.94%; (sulfamethoxazole) 85.18%; (sulfamonomethoxine) 83.45%; (chloramphenicol) 104.17%; (nitrofurazone) 91.81%; (furazolidone) 100.76%; and (furaltadone) 72.38%. Method detection limits ranged from 4 ppb (nitrofurazone) to 16 ppb (sulfamethazine). Some matrix interferences (3-7 ppb) were observed only with sulfonamides.     

微胶囊膜表面化学组成的XPS分析

采用XPS表面表征技术对生物微胶囊膜表面化学组成进行了分析。结果表明,海藻酸钠_壳聚糖_海藻酸钠(ACA)微胶囊表面带负电荷的含C基团与带正电荷的含N基团的相对百分含量分别为30·6%与60·4%,而海藻酸钠_聚赖氨酸_海藻酸钠(APA)微胶囊分别为42·3%与30·0%,因此ACA微胶囊表面比APA微胶囊带更多的正电荷,更有利于蛋白质吸附与细胞粘附。为深入了解生物微胶囊表面引起的机体反应过程、改进微胶囊性能,提供了理论依据。     

One-step purification of alpha-amylase from the cultivation supernatant of recombinant bacillus subtilis by high-speed counter-current chromatography with aqueous polymer two-phase systems

Purification of alpha-amylase from the cultivation supernatant of recombinant Bacillus subtilis by high-speed counter-current chromatography (HSCCC) in polyethylene glycol (PEG) 4000-inorganic salt aqueous polymer two-phase systems was studied. The effects of sodium chloride concentration on the partition coefficients of alpha-amylase and total protein were respectively tested in PEG4000-phosphate and PEG4000-citrate aqueous polymer two-phase systems to find the proper range of sodium chloride concentration for the HSCCC purification of alpha-amylase. Alpha-amylase was purified from the cultivation supernatant by HSCCC in PEG4000-phosphate system containing 2% (w/w) sodium chloride, yet with considerable loss of activity. PEG4000-citrate aqueous polymer two-phase system containing 2% (w/w) sodium chloride and supplemented with 0.56% (w/w) CaCl2 as protective agent was then successfully applied to purify alpha-amylase from cultivation supernatant by HSCCC to homogeneity and significantly increased the recovery of alpha-amylase activity from around 30 to 73.1%.     

Role of framework sodium versus local framework structure in determining the hydrothermal stability of MCM-41 mesostructures.

Two mesostructured MCM-41 silicas that differ dramatically in hydrothermal stability have been examined by (29)Si MAS NMR spectroscopy and pair distribution function (PDF) analysis of synchrotron X-ray scattering data. The less stable mesostructure assembled from sodium silicate and the substantially more stable derivative made from fumed silica possess equivalent local framework wall structures, as judged by NMR and PDF methods. Approximately 80% of the SiO(4) tetrahedra are fully cross-linked as Q(4) (Si(OSi)(4)) units in both calcined samples. Additionally, the structural correlation distances for the two materials are nearly identical, having values of 1.62(1), approximately 2.60, and 3.09(1) A for the Si-O, O-O, and nearest neighbor Si-Si distances in the framework. Sodium ions in the framework play a crucial role in limiting the hydrothermal stability of the mesostructure. Residual sodium ( approximately 0.05-0.10% Na(2)O) is retained in the MCM-41 made from sodium silicate, even after two ion exchange reactions with ammonium ions in more than 300 - fold excess. The entrapped framework sodium ions catalyze the collapse of the mesopores upon exposure to 20% steam at 800 degrees C for 5 h. The sodium - free mesostructure assembled from fumed silica retains an open framework under the same hydrothermal conditions. The stability of the fumed silica derivative, however, is greatly compromised when doped with as little as 0.10% Na(2)O, thus confirming the deleterious effect of sodium on hydrothermal stability.