低分子量丙烯酰胺—丙烯酸共聚物的研制

论述了过硫酸钾－亚硫酸氢钠氧化还原引发剂引发丙烯酰胺与丙烯酸水溶液共聚合反应工艺，得出了合成低分子量丙烯酰胺－丙烯酸共聚物的最佳工艺条件为：引发剂温度２５℃，丙烯酰胺浓度３．５ｍｏｌ／Ｌ，丙烯酸浓度０．７ｍｏｌ／Ｌ，过硫酸钾浓度０．００１１ｍｏｌ／Ｌ，过硫酸钾浓度０．００１１ｍｏｌ／Ｌ，亚硫酸氢钠浓度０．００２９ｍｏｌ／Ｌ，溴化铜浓度０￣０．０００４５ｍｏｌ／Ｌ。     

鲁米诺化学发光熄灭法测定铈的研究

目前,铈的测定方法报道较多［１,２］,但其化学发光分析法却未见文献报道。在适宜条件下,铈对鲁米诺－过氧化氢－铬（Ⅲ）体系存在熄灭效应,熄灭程度与浓度呈良好的线性关系,以此建立了铈的流动注射化学发光分析法。该法线性范围为１．０×１０－６～１．０×１０－４ｍｏｌ／Ｌ,相关系数大于０．９９８０,检出限为３×１０－７ｍｏｌ／Ｌ铈,用于合成样品分析,结果满意。１　实验部分１．１　试剂１．０×１０－４ｇ／ｍＬ铬（Ⅲ）标准溶液：用Ｃｒ－Ｃｌ３·６Ｈ２Ｏ（Ａ．Ｒ．）配制;５×１０－４ｍｏｌ／Ｌ鲁米诺溶液：称取８…     

硫代硫酸盐法添加氯化钠和十二烷基磺酸钠浸取金矿

对湖北氧化铁型金矿进行了Ｎａ２Ｓ２Ｏ３法添加ＮａＣｌ而不加Ｃｕ２＋的浸取条件优化研究,当［Ｓ２Ｏ２－３］＝０．８ｍｏｌ／Ｌ、［ＮＨ３］＝１～２ｍｏｌ／Ｌ、［ＮａＣｌ］＝１．０ｍｏｌ／Ｌ、浸取温度５０℃、浸取时间为３ｈ时,浸出率达到９８％．对广东河台、山东招远硫化金矿进行了浸取研究,当［Ｓ２Ｏ３２－］＝０．８ｍｏｌ／Ｌ、［ＮＨ３］＝２ｍｏｌ／Ｌ、［ＮａＣｌ］＝１．０ｍｏｌ／Ｌ、十二烷基磺酸钠１１．０ｍｏｌ／Ｌ、浸取温度５０℃、浸取时间３ｈ时,浸取率分别达到９６％和９３％．     

液膜法提取硝酸水溶液中Ag^＋的工艺过程

液膜的组成为：２％石油硫醚－４％多丁二酰亚胺－９４％煤油，内相试剂为：１～ｍｏｌ／Ｌ的氨水溶液。较为适宜的操作条件为：乳水比为１：３；内油比为０．８：１；外相硝酸浓度为０．５～１ｍｏｌ／Ｌ；常温操作。当料液中的银离子浓度小于８００ｐｐｍ时，一次提取率可达９７％以上。本工艺具有分离速度快、效率高、选择性好等优点。     

间接电合成法制取双醛淀粉

提出了一种合成双醛淀粉（ＤＡＳ） 的新方法间接电合成法。在阳离子交换膜做隔膜的两室电解槽中,铅板做阳极,铁板做阴极,把淀粉和碘酸钠的酸性水溶液直接加入阳极室电解,即合成ＤＡＳ。优选电解条件：阳极电解液中ｃ（ＮａＩＯ３） ＝ ０－０５ ｍｏｌ／Ｌ,ｃ（Ｈ２ＳＯ４） ＝ ０－１ ｍｏｌ／Ｌ,ｗ（ 淀粉） ＝ ７ ％ ;阴极液为ｃ（Ｈ２ＳＯ４） ＝ ０－１ ｍｏｌ／Ｌ的稀硫酸;电流密度２ Ａ／ｄｍ２ 。在此条件下电流效率大于０－５ 。     

固定化细胞生产L－苹果酸新工艺及动力学研究

对产氨短杆菌ＭＡ－２固定化细胞在富马酸铵体系中转化生成Ｌ－苹果酸的优化工艺条件做了探讨，结果表明，富马酸铵浓度为１．８ｍｏｌ／Ｌ，ｐＨ７．０～８．０，反应温度为３７℃时，Ｌ－苹果酸得率达２００ｇ／Ｌ左右。同时，对固定化细胞的动力学进行了研究，结果为：ｒ（ｍａｘ）＝５８ｍｍｏｌ／（Ｌ·ｈ·ｇ固定化湿细胞）），Ｋｍ＝６．２５×１Ｏ￣（－２）ｍｏｌ／Ｌ，Ｐ＿ｍ＝１．５６ｍｏｌ／Ｌ     

理化因子对嗜盐隐杆藻细胞生长及胞外多糖产量的影响

比较不同ＮａＣｌ、Ｃａ２＋、ＰＯ３－４等离子浓度对嗜盐隐杆藻（Ａｐｈａｎｏｔｈｅｃｅｈａｌｏｐｈｙｔｉｃａ）细胞生长及胞外多糖（Ｅｘｏｐｏｌｙｓａｃ－ｃｈａｒｉｄｅＥＰＳ）产量的影响。在各影响因子不同浓度的培养条件下,０．５ｍｏｌ／Ｌ的ＮａＣｌ、１．０ｇ／Ｌ的Ｃａ（ＮＯ３）２·４Ｈ２Ｏ、０．１ｇ／Ｌ的ＫＨ２ＰＯ４分别是其最佳生长浓度。ＥＰＳ的产量在０．５ｍｏｌ／ＬＮａＣｌ、,０．５ｇ／ＬＣａ（ＮＯ３）２·４Ｈ２Ｏ、０．５ｇ／Ｌ的ＫＨ２ＰＯ４培养条件下最高。在较低的Ｃａ２＋、Ｍｇ２＋、ＰＯ３－４浓度下可提高ＥＰＳ产率。     

氧化还原引发木薯淀粉与丙烯酰胺接枝共聚的研究

以木薯淀粉和丙烯酰胺为原料,采用氧化还原引发体系合成淀粉-丙烯酰胺接枝共聚物,研究了温度、引发剂浓度、单体浓度以及反应时间对聚合反应的影响。结果表明：采用氧化还原引发剂可以使聚合反应低温快速进行。实验最佳条件：反应温度为40℃,引发剂浓度为4mmol／L,单体质量浓度为85mg／mL,反应时间为3h。     

固定化黄色短杆菌生产L－苹果酸新工艺及动力学研究

研究了固定化黄色短杆菌ＭＡ－３在富马酸盐体系中转化生成Ｌ－苹果酸的新工艺，研究结果表明当富马酸铵盐浓度为１．８ｍｏｌ／Ｌ，体系ｐＨ为７．０～８．０，反应温度为３７℃时，Ｌ－苹果酸的得率达２１６ｇ／Ｌ。对固定化黄色短杆菌的动力学研究结果为Ｖｍａｘ＝７６ｍｍｏｌ／［Ｌ·ｈ·ｇ（固定化湿细胞）］，Ｋｍ＝４．７６×１０－２ｍｏｌ／Ｌ，Ｃｐｍ＝１．６９ｍｏｌ／Ｌ。     

溶胶—凝胶法制备超细高纯氧化铝

采用溶胶—凝胶（ｓｏｌ－ｇｅｌ）法制备了超细高纯Ａｌ２Ｏ３。通过考察溶液的初始ｐＨ值、柠檬酸用量、Ａｌ３＋浓度以及反应温度等因素对合成粒子的平均粒径的影响规律，确定了制备氧化铝超细粒子的工艺条件：ｐＨ＝０．４０，ＣＯＡｌ３＋＝０．１ｍｏｌ／Ｌ～０．２ｍｏｌ／Ｌ，ＣＯＡｌ３＋：Ｃｏｃｉｔ＝１∶３，Ｔ＝７０℃。本法制备的氧化铝超细粒子为球形，平均粒径为１４ｎｍ，纯度达９９．９８％。     

球形纤维素珠体-AN-AM接枝共聚物的制备

以球形纤维素珠体为原料,丙烯腈(AN)和丙烯酰胺(AM)为单体,硝酸铈铵和过硫酸钾(KPS)为引发剂,制备纤维素珠体-AN-AM接枝共聚物,并通过正交单因素实验,研究了反应温度、引发剂用量、单体用量、反应时间等因素对接枝效果的影响。实验结果表明:当反应温度为60℃,引发剂硝酸铈铵用量为20%,KPS用量为15%(引发剂与单体AN的质量百分比),单体AN浓度为0.75 mol/L,AM浓度为0.28 mol/L,硝酸浓度为0.14 mol/L,反应时间为3 h时,接枝效果最好。此条件下,AN、AM与纤维素的接枝率可达259.4%,接枝效率可达49.40%。     

反相乳液聚合法合成淀粉接枝丙烯酰胺的工艺研究

研究以玉米淀粉为原料,反相乳液体系中淀粉与丙烯酰胺接枝共聚反应规律。考察引发剂浓度、乳化剂用量、丙烯酰胺单体与玉米淀粉质量比接枝共聚反应的影响。通过单因素实验,获得最佳工艺条件:引发剂浓度为6mmol/L,乳化剂用量5%,丙烯酰胺单体与玉米淀粉的质量比为1.5∶1。在此条件下,可制备得到单体转化率95.46%、接枝效率88.12%、特性粘度410 mL/g的接枝共聚物,该接枝物比相对分子质量500万的聚丙烯酰胺的絮凝性能更好,在用量为25 mg/L时,对高岭土水样的浊度去除率达到88.6%。     

玉米淀粉接枝丙烯酰胺制备高吸水性树脂

用硝酸铈铵作引发剂,通过水溶液聚合法制得了玉米淀粉接枝丙烯酰胺高吸水性树脂。研究了交联剂及引发剂用量、碱用量、反应温度以及反应时间等对吸水率的影响。得到的最佳反应条件为:交联剂和引发剂与丙烯酰胺的摩尔比分别为1.0×10-5和3.0×10-3,碱与丙烯酰胺的摩尔比为1.50,反应温度60℃,反应时间2 h。在室温下制得的高吸水树脂,30 m in每克吸蒸馏水和自来水分别约为其自身质量的600和170倍。     

微波辐射下淀粉-丙烯酰胺接枝共聚物的合成

以硝酸铈铵作为引发剂、丙烯酰胺为单体,用微波辐射法合成了淀粉接枝丙烯酰胺共聚物。探讨了反应时间、引发剂浓度、单体和淀粉质量比和反应温度等因素对接枝反应的影响。正交实验确定的最优工艺条件为:反应时间20 m in,引发剂浓度4 mmol/L,丙烯酰胺和淀粉质量比2.5∶1,反应温度55℃,最高接枝率和接枝效率分别达到211.6%和74.3%。     

Water-soluble copolymers. XI. Selectivity in the graft copolymerization of acrylamide/N-(1,1-dimethyl-3-oxybutyl)acrylamide comonomers onto dextran by Ce(IV)-induced initiation

Characteristic behavior in the graft copolymerization of acrylamide/N-(1,1-dimethyl-3-oxybutyl)acrylamide (AM/DAAM) comonomers onto dextran by Ce(IV)-induced initiation was investigated. From a preliminary study, it was found that ceric ammonium nitrate polymerized AM/DAAM comonomer mixtures and diacetone acrylamide, but not acrylamide alone in the aqueous solution. The effect of grafting conditions on the graft copolymerization product was studied with the aid of aqueous size exclusion chromatography and the anthrone reagent. The selectivity of formation of the graft copolymer over random copolymer was found to increase as the reaction temperature and AM/DAAM ratio increased and as both the Ce(IV)/Dextran molar ratio and HNO₃ concentration decreased. After establishing optimum grafting conditions, graft copolymer samples were prepared, and their aqueous solution behavior studied as functions of structure, temperature, and added salts.     

淀粉与丙烯酰胺的接枝共聚

本文研究了在硝酸铈铵作用下，淀粉和丙烯酰胺接枝共聚合的反应规律，探讨了引发剂浓度、单体浓度、ｐＨ值、反应时间和反应温度对接枝聚合的影响，并对不同的引发体系引发淀粉—丙烯酰胺接枝聚合进行了比较，结果表明，以硝酸铈铵引发的淀粉—丙烯酰胺接枝聚合所产生的均聚物少，引发效率高。     

Graft copolymerization of acrylamide–methylacrylate comonomers onto cellulose using ceric ammonium nitrate

The graft copolymerization of acrylamide–methylacrylate comonomers was carried out using ceric ammonium nitrate as initiator in the presence of nitric acid at 25 ± 1°C. The effects of feed molarity, feed composition, reaction time, and temperature on graft yield (%G) and other grafting parameters were investigated. The determination of rate of ceric (IV) ions disappearance as a function of feed molarity and reaction time was useful in the determination of the rate of ceric (IV) ions consumption during graft copolymerization. The graft yield (%G) in the presence of acrylamide increases because of the synergistic effect of acrylamide comonomer. The composition of the grafted chains (F_AAm) varies on varying the feed composition and reaction temperature but is almost constant during feed molarity variation. The Mayo and Lewis method was used to determine the reactivity ratios of acrylamide (r₁) and methylacrylate (r₂), which are 0.65 and 1.07, respectively. The product of reactivity ratio (r₁ r₂) is less then unity; hence, an alternate arrangement of comonomer blocks in the grafted copolymer chain is proposed. The rate of graft copolymerization of comonomers onto cellulose is second power to the concentration of comonomers and square root to the concentration of ceric ammonium nitrate. Suitable reaction steps for graft copolymerization of comonomers onto cellulose are proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2631–2642, 2002     

引发剂对纤维素接枝丙烯酰胺反应的影响

分别以硝酸铈铵、过硫酸钾和过硫酸钾/亚硫酸钠为引发剂,以马尾松漂白硫酸盐浆纸浆纤维素为骨架接枝丙烯酰胺,在单体浓度为0.75 mol/L、温度为45℃、反应时间为3 h时,得到硝酸铈铵和过硫酸钾的最佳浓度为3.0 mmol/L和5.0 mmol/L,过硫酸钾/亚硫酸钠在用量为6%时的最佳质量比为1.5,三者相应的接枝率分别为40%、48%和60%。同时比较了不同条件下三种引发剂的接枝效果,结果表明,过硫酸钾/亚硫酸钠的接枝效果最好,但均聚物含量高;硝酸铈铵作为引发剂虽然接枝效果不及前两者,但均聚物含量很低。     

Graft copolymerization of acrylonitrile onto hemicellulose using ceric ammonium nitrate

The ability of ceric ammonium nitrate to induce graft copolymerization of acrylonitrile onto hemicellulose was investigated. The graft yield depends on monomer and initiator concentrations as well as reaction time and temperature. Chemical analysis of the reaction product of hemicellulose and acrylonitrile in the presence of ceric ammonium nitrate revealed that the ceric ammonium nitrate acted as initiator for polymerization of acrylonitrile and as oxidizing agent for hemicellulose. Proof for grafting of hemicellulose was provided through IR analysis.     

Ceric ammonium nitrate‐initiated graft copolymerization of acrylamide onto Cassia tora gum

Graft copolymerization of acrylamide onto Cassia tora gum was studied in an aqueous medium using ceric ammonium nitrate‐nitric acid as the redox initiator. To optimize the reaction conditions for obtaining maximum percent grafting, the concentrations of Cassia tora gum, ceric ammonium nitrate, acrylamide, and nitric acid, time, and temperature were varied. Results are discussed and a reaction mechanism is proposed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3250–3255, 2002