反丁烯二酸酯类共聚物的透气性能

反丁烯二酸酯类聚合物的气体分离性能研究已有许多报道。聚反丁烯二酸二叔丁酯(Po_2=130barrer,ao_2/N_2=3.7)和聚反丁烯二酸二异丙酯(Po_2=51barrer,ao_2/N_2=2.9)等都具有较好的氧氮分离性能。但是,由于这类聚合物的脆性很大,使其应用受到较大的限制。本文报道不同系列的反丁烯二酸酯类共聚物的合成和它们的氧氮透过性能。 实验部分     

CF4等离子体表面氟化PTMSP膜

本文对聚三甲基硅基丙炔(PTMSP)膜进行CF_4等离子体表面氟化研究。改性的PTMSP膜氧氮选择性显著提高(P_(O_2)/P_(N_2)=4-5,P_(O_2)=10~2-10~3barrer)。等离子体改性条件,如处理时间、单体压力、放电功率对PTMSP膜透气性的影响进行了研究。XPS谱分析表明改性后,膜表层化学组成发生了显著变化、碳硅含量大幅度减小,氟含量随着处理程度的增加而增加,氟碳比与膜的选择性有着密切的关系,当 F/C>1时,膜的P_(O_2)/P_(N_2)可达4以上。     

含有机硅多嵌段共聚物的研究Ⅳ.含有机硅多嵌段共聚物的富氧功能

研究了几种新型含有机硅二元和三元多嵌段共聚物的氧、氮选择透过性能。其中双酚A聚羟基醚-聚二甲基硅氧烷二元多嵌段共聚物-(PHE-PDMS)_n的透氧系数Po_2=510Barrer、氧氮分离系数a o_2/N_2=2.2,聚苯醚-聚二甲基硅氧烷-聚对羟基苯乙烯三元多嵌段共聚物-(PPO-PDMS-pHS)_n的Po_2=156 Barrer、do_2/N_2=2.4,两者都具有良好的力学性能。此外,含有机硅三元多嵌段共聚物与聚三甲硅基丙炔(PTMSP)起薄复合后,改善了PTMSP超薄膜的透气稳定性。其JO_2≈1.0×10~(-3)cm~2/cm~2·s·cmHg,do_2/N_2≥2.0。     

新型含钴硅橡胶离聚体膜的富氧性能

硅橡胶 ( PDMS)是最早使用的气体分离膜材料 ,其氧透过系数较高 ( PO2 =6 0 0 Barrer) ,但氧氮分离系数低 ( αO2 /N2 =2 .0 ) ,成膜性及膜强度差 ,因而限制了其应用 .PDMS改性一直是气体分离膜研究的重要课题[1] ,提高氧氮分离性 ,改善成膜性 ,而不影响其透气性 ,成为人们追求     

等离子体改性提高PTMSP膜氧氮选择性

膜材料中迄今以聚三甲基硅基丙炔(PTMSP)的透气速率最大,其氧透过速率比PDMS高一个数量级,但氧氮分离系数小,透气性不稳定。改性PTMSP,以提高其透气选择性和透气速率稳定性引起人们的极大关注。本文报道,在外极管式电容耦合反应器中,     

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。     

密胺苯二醛多孔聚合物/聚二甲基硅氧烷混合基质膜的制备及气体分离性能

以溶液复合成膜法制备了密胺苯二醛多孔聚合物(MA)/聚二甲基硅氧烷(PDMS)混合基质膜,利用扫描电镜(SEM)表征了混合基质膜的形貌。考察了不同MA用量下MA/PDMS混合基质膜的气体分离性能,结果表明,MA的加入可以在提高PDMS膜渗透系数的同时提高CO_2气体分离选择性;随着混合基质膜中MA含量的增加,混合基质膜的渗透系数均明显提高,气体分离选择性则先增大后减小。双组分混合气体分离测试结果表明,MA/PDMS(1.2%(w,质量分数))混合基质膜对CO_2/N_2和CO_2/CH_4的分离选择性分别是19.2和6.0,CO_2的渗透系数达到8100Barrer,均高于纯PDMS膜。MA/PDMS(1.2%(w))混合基质膜对CO_2/N_2混合气的分离性能突破了Robeson上限。     

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。     

邻苯二甲酸二辛酯增塑聚氯乙烯膜的富氧分离性能

本文研究了DOP含量为0—70%(重量)的增塑PVC膜的透氧性能,指出DOP含量为50%左右的PVC膜要比纯PVC膜的气体透过率提高二个数量级,约为1.7×10^-9cm³。cm/cm²·s·cmHg,氧氮分离系数为4。DOP含量为20%的PVC膜有较高的氧氮分离系数,约为6.9。     

聚[1—（三甲硅基）1—丙炔]—一种有希望的气体分离膜材料

聚[1-(三甲硅基)]-丙炔(PTMSP)膜的气体透过速率高于目前已知的,不管在室温是玻璃态还是橡胶态的任何聚合物.PTMSP在室温是玻璃态.PTMSP的高透气性主要来源于极高的对气体溶解度及高扩散系数,而这是因为在这种玻璃态聚合物中,有大量处于非松弛区域的自由体积.PTMSP的最大问题是它的高透气性随着时间的过去和热历史而衰减.近来,为解决这一问题进行了大量的努力,如加入低挥发材料,氟化、溴化,与其它单体共聚,与其它聚合物共混等.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.