溴代及胺交联聚苯醚（PPO）膜的气体透过行为

对聚苯醚(PPO)进行了苯环溴代、甲基溴代以及胺交联,发现苯环溴代可提高O_2、N_2透过率(P),而选择性(α)基本不变。甲基溴代则相反,P降低、α有明显提高。调节两者比例可得到P、α兼优的O_2、N_2分离膜。甲基溴代后进一步胺交联可得到α更高、耐溶剂的膜材料。     

聚三甲硅基丙炔膜表面改性的XPS研究——Ⅰ.用N-溴代丁二酰亚胺的表面改性

用N-溴代丁二酰亚胺的丙酮溶液在回流温度下对三甲硅基丙炔的均聚物和共聚物作了表面改性。XPS的研究表明,试样表面层中Br原子含量随溴化时间的增长而增加,C_(IS)谱变宽且产生来自C-O和C-Br结构的新谱线。红外光谱证明溴化反应产生CH_2Br结构。溴化使膜的气透性发生相应的变化,即α_(O_2/N_2)值增高,P_(O_2)值降低。     

TMSP—PMDSP共聚物膜的氧,氮透过性

研究了三甲基硅丙炔(TMSP) 和五甲基二硅丙炔(PMDSP) 的共聚物膜对O_2、N_2气体的透过行为。发现 TMSP-PMDSP共聚物膜对O_2、N_2气体的透过活化能为负值,透过系数随温度升高而下降;受热历程不同,气体在膜中的透过行为也不相同。膜两侧气体压差不同时,气体在膜中的透过系数亦发生变化。用氟化物HFBM对共聚物膜表面进行了化学改性,改性膜的P_(O_2)/PN_2值达到3.52。     

Wohl-Ziegler反应的研究 芳香醚的侧链溴化与苯环溴化

本文报告对-甲苯甲醚在不同情况下与 N-溴代丁二酰亚胺(NBS)的作用。作者认为溶剂是使溴化反应具选择性的一种重要因素。用四氯化碳则可以得到收率为65%的侧链溴化产物,如用冰醋酸则得到收率为68%的苯环溴化产物。我们在研究苯甲醚与 NBS 作用时,观察到有溴放出,而后又有溴化氢气体出现,由于这些现象,使我们进一步研究 NBS与数种溶剂,例如四氯化碳,氯仿,苯及苯腈的作用。同样发现都在不同的时间内能放出溴,并且过氧化苯甲酰对于在每一种上述溶剂中进行的反应都具催化作用,加速放出溴。我们认为芳香醚与 NBS 所进行的苯环溴化的反应机构基本上是与溴的苯环溴化的反应机构相同。据此我们可以解释,(1)何以三氯化铝与过氧化苯甲酰都能够作为苯环溴化的催化剂,(2)何以间-甲苯甲醚与间-二甲氧基苯即使在四氯化碳中也容易苯环溴化,以及(3)何以间-甲苯甲醚不易进行侧链溴化,此外也研究对-甲氧基苯乙酮的侧链溴化与苯环溴化。我们研究对甲氧基乙苯与2,4-二甲氧基乙苯的溴化反应,发现前者很容易进行侧链溴化,这是符合于游离基丙烯型溴化反应机构的,而后者即使在四氯化碳中首先是苯环溴化,如果再加一克分子 NBS,则第二个溴原子能进入侧链。这结果说明在很活化的苯环上即使有侧链,首先、还是苯环溴化。我们也测定了溴进入苯环的位置,这些事实都符合于我们所设想的,芳香醚的 Wohl-Ziegler 苯环溴化基本上是溴进行苯环溴化的吸电子反应机构。2,4-二甲氧基-5-溴苯甲酸可以从2,4-二甲氧基苯乙酮经侧链氧化再进行苯环溴化合成,方法简便,收率良好。     

含硅聚酰亚胺和有机硅改性的联苯型聚酰亚胺透气性能的研究

本文合成了一系列均聚和共聚酰亚胺,研究了它们对H_2、O_2和N_2三种气体的透过性能与分子结构之间的关系。结果表明,在30℃和6atm的条件下,SiDA-ODA对H_2和O_2的透过系数分别为11.7和0.764Barrer,比BPDA-ODA高一个数量级;H_2/N_2和O_2/N_2分离系数分别为113和7.4在(BPDA/SiDA)-ODA共聚物中,随着SiDA含量的增加,其透氢系数P_(H_2)和透氧系数P_(O_2)均有较大的增加,而H_2/N_2和O_2/N_2分离系数则降低。当SiDA含量占二酐组分的60%时,P_(H_2)和P_(H_2)/P_(N_2)分离系数分别达8.78Barrer和147。     

咔唑的溴化研究

咔唑类化合物在很多领域的应用研究受到了科学家的广泛关注,特别在有机光电分子器件、太阳能电池材料、彩色液晶材料等前沿科技领域,展现出广阔的应用前景。但由于咔唑环上的电性较强,目前的咔唑溴化方法很难得到高纯溴代咔唑单体。采用氮酰基化保护,改变芳香环上的电子云分布,增强溴代选择性,通过H_2O_2-HBr氧化溴化体系,合成两种不同取代的溴代咔唑,考察了合成温度、反应时间及物料配比等因素对反应的影响,利用熔点和~1H-NMR对产物进行表征。     

一步水热合成Y-Co_3O_4复合氧化物催化剂及催化分解N_2O（英文）

用一步水热、分步水热、浸渍等方法分别制备Y-Co_3O_4复合氧化物,用于催化分解N_2O的反应,其中,一步水热法制备的催化剂活性较高。再用一步水热法制备了不同Y/Co物质的量比的Y-Co_3O_4复合氧化物,在优化出的催化剂(0. 03YCo_3O_4)表面浸渍K_2CO_3溶液,制备K改性催化剂(0. 02K/0. 03Y-Co_3O_4)。用X射线衍射(XRD)、N_2物理吸附、H_2程序升温还原(H_2-TPR)、O_2程序升温脱附(O_2-TPD)、扫描电镜(SEM)、X射线光电子谱(XPS)等技术表征催化剂结构。研究发现,Co_3O_4和Y-Co_3O_4同为尖晶石结构,但Y-Co_3O_4的催化活性显著高于Co_3O_4。K改性增加了催化剂表面的活性位(Co~(2+)),还有利于吸附氧的脱除,从而提高了催化剂活性。在无氧无水、有氧无水、有氧有水气氛中,K改性催化剂上的N_2O全分解温度分别为325、350、375℃,催化剂活性较高。有氧有水气氛350℃连续反应50 h,K改性催化剂上N_2O分解率保持90%以上,稳定性较高。研究发现,Y-Co_3O_4及K改性催化剂上N_2O分解反应的Ea和lnA之间存在动力学补偿效应。     

Ni/Al_2O_3催化2-甲基呋喃加氢制2-甲基四氢呋喃性能的研究

采用浸渍法制备了不同NiO含量的Ni/Al_2O_3催化剂,并进行了2-甲基呋喃加氢制2-甲基四氢呋喃性能的考察。结果表明,在制备的NiO负载量为10%、20%、25%、30%和40%的Ni/Al_2O_3催化剂中,随着NiO负载量增加,加氢反应的选择性与2-甲基呋喃的转化率均呈现出先增加后减小的趋势。其原因是由于适当增加NiO负载量有利于催化剂表面活性中心的形成,有利于加氢反应的进行;但是过度负载的NiO容易堵塞Al_2O_3载体中的介孔通道,降低反应的转化率与选择性。在釜式反应器中进行反应,对加氢反应条件进行了优化,发现在反应压力为3 MPa、反应温度150℃、机械搅拌速率为1000 r/min时,Ni/Al_2O_3催化2-甲基呋喃加氢制2-甲基四氢呋喃具有较高的选择性。当NiO负载量为25%时,2-甲基四氢呋喃的选择性最高为97.1%,2-甲基呋喃的转化率达到99.4%。     

不同阳离子(NH_4~+,Na~+,K~+,Ca~(2+))溴化物对商用SCR催化剂化学中毒影响机制研究（英文）

燃煤飞灰中的碱金属和碱土金属对NH_3-SCR催化剂的活性有显著的影响.近年来,研究者针对碱金属/碱土金属氧化物对SCR催化剂中毒作用开展了大量研究.另一方面,研究普遍认为,含溴化合物对提高SCR催化剂汞氧化性能具有明显促进作用.目前为止,针对碱金属/碱土金属溴化物对SCR催化剂影响的系统研究较少.我们课题组系统研究了不同阳离子的溴化物(NH_4Br,NaBr,KBr和CaBr_2)对商用V_2O_5-WO_3/TiO_2催化剂性能的影响.与未中毒样品相比,KBr中毒后的催化剂(记为L-KBr)上NO_x转化率明显下降,而NaBr和CaBr_2中毒的催化剂(分别记为L-NaBr和L-CaBr)上的SCR活性也有一定程度的降低.另外L-NaBr,L-KBr和L-CaBr催化剂的N_2选择性较差.XPS结果显示,KBr中毒后化学吸附氧(O_α)比例减小;同时,KBr中毒后还原性和表面酸度降低,这些可能是导致L-KBr催化剂的活性和N_2选择性变差的主要原因.对于L-CaBr催化剂,中毒后化学吸附氧O_α比例有所增加,这与H2-TPR结果显示可还原性增强一致.O_2-TPO结果显示,L-CaBr催化剂可氧化性降低,说明CaB_r2中毒还是影响到催化剂表面的氧化还原循环.催化剂CaBr_2中毒后表面被覆盖减少了反应活性位数量,但表面酸性的增强可能会抵消活性位点损失带来的负面影响.NH_3氧化结果显示,NH_3在L-CaBr催化剂表面发生过氧化反应,特别是高温下生成较多N_2O,降低N_2选择性,这可能是高温下L-CaBr催化剂SCR活性和N_2选择性下降的重要原因.CO_2-TPD结果表明,L-KBr和L-CaBr催化剂表面碱性强度增加,可能有助于增加NO_x物种的吸附量.基于以上活性评价和表征分析结果,我们尝试建立了不同溴化物中毒的催化剂表面酸碱性、氧化还原和催化性能之间的关系.     

磷改性Cr2O3/Al2O3催化4-乙基酚转化制轻质芳烃

以烷基酚转化为轻质芳烃(苯和甲苯)为目标,制备了Cr_2O_3/Al_2O_3催化剂,并以4-乙基酚为模型化合物研究了其加氢反应性能。体积空速、氢油比、反应压力和温度升高时,脱烷基率、芳烃总选择性、轻质芳烃选择性呈先增大后减小的趋势,反应温度对转化率影响较大。以不同浓度磷酸对Cr_2O_3/Al_2O_3进行改性,随着磷酸用量的增大,催化剂酸量总体增大,主要是弱酸和中强酸,酸强度先增加后降低,磷酸用量较高时,弱酸增加幅度较大。与未改性相比,质量分数8%磷酸改性Cr_2O_3/Al_2O_3上4-乙基酚转化率99.5%,脱烷基率提升9.4%,达74.4%,轻质芳烃选择性提高4.0%,达到57.0%,以较高选择性实现了转化制轻质芳烃,同时,芳烃总选择性高达80.4%,较高程度保持了芳环不被破坏。提出了Cr_2O_3/Al_2O_3上4-乙基酚加氢反应的路径并对反应机理进行了研究。     

由聚合物结构预测气体的透过性能

本文利用基团加和法,对20多种常见聚合物的自由体积和内聚能进行了计算。发现氧气和氮气在聚合物膜中的透过率与自由体积和内聚能的比值有直接关系。此比值越大,气体的透过率越大,透过率的对数与自由体积和内聚能的比值基本呈线性关系。据此,对未知聚合物可根据其化学结构,从已有的基团数据计算该比值,从而预测它对氧气和氮气的透过性能。     

共聚聚酰亚胺膜材料的合成及其气体渗透性能研究

以2,2′-双(3,4-二羧基苯基)六氟丙烷二酐(6FDA)作为二酐单体,1,3-苯二胺(mPDA)和2,6-二氨基甲苯(2,6-DAT)为二胺单体,采用溶液共缩聚方法合成了一系列新型共聚聚酰亚胺(6FDA-2,6-DAT/mPDA),该类聚合物均能溶于DMF、DMAc、NMP等极性非质子溶剂中,具有较好的成膜性.测试了H2、N2、O2、CH4、CO25种气体在6FDA-2,6-DAT/mPDA共聚聚酰亚胺致密膜中的渗透性能.结果显示,该系列共聚物具有优异的分离性能.在35℃,0.2 MPa下,H2/N2、O2/N2、CO2/CH4的分离性能均接近或突破Robeson上限.     

聚乙烯醇缩醛膜的加湿透气性

前曾报道聚乙烯醇(PVA)与脂肪醛缩合后亲水性的羟基减少,影响到其薄膜的透湿性和透气性,本文考察PVA及其三种脂肪族缩醛物膜在加湿条件下的透气性。 PVA膜为10％PVA水溶液用流涎法制成。缩醛膜为PVA缩醛衍生     

Different specificities in the bromination of 6-(2-furyl)imidazo[2,1-b]thiazole and its derivatives with 1 mole of bromine

The action of 1 mole of bromine on 6-(2′-furyl)imidazo[2,1-b]thiazole, its 2-methyl-, 3-methyl-, and 2,3-dimethyl-substituted derivatives, and their hydrobromides in chloroform and glacial acetic acid was studied. The bromination of bases containing a methyl group in the 3 position leads primarily to the 5′-derivatives with respect to the furan ring in chloroform, whereas in the remaining cases 5-bromo derivatives with respect to the imidazothiazole system are formed. Compounds of the latter type are formed by the action of bromine in glacial acetic acid or of sodium hypobromite in alkaline media on the bases. The hydrobromides are brominated in both acetic acid and chloroform, regardless of the substituents in the thiazole ring, primarily in the 5′ position of the furan ring. The structures of the bromination products were proved by means of alternative syntheses, thin-layer chromatography, and the PMR spectra.     

Quasielastic neutron scattering of poly(methyl phenyl siloxane) in the bulk and under severe confinement

Quasielastic neutron scattering was utilized to investigate the influence of confinement on polymer dynamics. Poly(methyl phenyl siloxane) chains were studied in the bulk as well as severely confined within the approximately 1-2 nm interlayer spacing of intercalated polymer/layered organosilicate nanohybrids. The temperature dependence of the energy resolved elastic scattering measurements for the homopolymer and the nanocomposites exhibit two distinct relaxation steps: one due to the methyl group rotation and one that corresponds to the phenyl ring flip and the segmental motion. Quasielastic incoherent measurements show that the very local process of methyl rotation is insensitive to the polymer glass transition temperature and exhibits a wave-vector independent relaxation time and a low activation energy, whereas it is not affected at all by the confinement. At temperatures just above the calorimetric glass transition temperature, the observed motion is the phenyl ring motion, whereas the segmental motion is clearly identified for temperatures about 60 K higher than the glass transition temperature. For the nanohybrid, the segmental motion is found to be strongly coupled to the motion of the surfactant chains for temperatures above the calorimetric glass transition temperature of the bulk polymer. However, the mean square displacement data show that the segmental motion in confinement is faster than that of the bulk polymer even after the contribution of the surfactant chains is taken into consideration.     

Synthesis of 2-carbethoxy-3-methyl-4-hydroxybenzofuran derivatives

A number of 2-.carbethoxy-3-methylbenzofuran derivatives were synthesized. A 5,5-gem-dibromo derivative was obtained in the bromination of 2-carbethoxy-3-methyl-4-oxo-4, 5,6,7,tetrahydrobenzofuran. Dehydrobromination of this, dibromo derivative gave 2-carbethoxy-3-methyl-4-hydroxy-5-bromobenzofuran. Depending on the structure of the starting compound and the brominating agent, the bromine in the bromination of 2-carbethoxy-3-methyl-4-hydroxy- and 4-acetoxybenzofurans with bromine and N-bromosuccinimide is incorporated either in the methyl group or in 5 and 7 positions of the benzofuran ring. The nitration of 2-carbethoxy-3-methyl-4-hydroxybenzofuran and its bromo derivative leads to 5-nitro- and 5,7-dinitrobenzofuran derivatives. The structures of the synthesized benzofuran derivatives were established by means of the PMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 27–29, January, 1980.     

聚酰亚胺膜的分子结构与透气性能之间关系的研究 I.

膜法是近十余年来发展起来的一种新型分离技术,是分离混合气体最为节能的方法。其关键是气体膜分离器,它的分离特性、使用条件和寿命主要取决于膜材料的选择。目前工业上使用的高分子气体分离膜材料主要有聚砜、醋酸纤维素、改性聚苯醚、改性聚硅氧烷、     

Preparation of phenyl‐modified natural rubber in latex stage

Phenyl‐modified natural rubber was prepared in latex stage by bromination of deproteinized natural rubber followed by Suzuki‐Miyaura cross‐coupling reaction. First, the bromination of natural rubber was carried out using N‐bromosuccinimide in latex stage. The bromine atom content increased as amount of N‐bromosuccinimide increased. Second, the allylic bromine atom was replaced with a phenyl group using phenyl boronic acid in the presence of a palladium catalyst, according to the Suzuki‐Miyaura cross‐coupling reaction in latex stage. The resulting products were characterized by nuclear magnetic resonance (NMR) spectroscopy. Signal at 7.13 ppm was assigned to the phenyl group of the product, while signals at 3.98, 4.14, and 4.44 ppm were assigned to the remaining allylic brominated cis‐1,4‐isoprene units. The estimated phenyl group content and the conversion of the Suzuki‐Miyaura cross‐coupling reaction were 1.32 and 23.7 mol%, respectively. Glass transition temperature (T_g) of deproteinized natural rubber increased from ?62°C to ?46.7°C, when the phenyl group was introduced into the rubber.     

Microbiological reductions of chromen-4-one derivatives

From the microbiological reductions of 2-acetyl or 2-benzoylchromen-4-one both enantiomers of the corresponding alcohols were obtained with high enantiomeric excess. The absolute configurations were determined directly by an X-ray structural determination. The results obtained showed that for most of the microorganisms tested, an inversion of the configuration of the alcohol occurred with the change of the substituent (methyl to phenyl group) in position 2, but also with the presence of a bromine atom in position 6 of the aromatic ring, positioned quite far from the prochiral centre.