新型泡沫稳定剂氧化叔胺的合成研究

介绍了用十二胺合成氧化叔胺的方法,研究了叔胺及氧化叔胺的合成工艺条件和影响反应的因素.泡沫稳定实验显示氧化叔胺是一种较好的新型泡沫稳定剂.     

Diamino telechelic polybutadienes for solventless styrene-butadiene-styrene (SBS) triblock copolymer formation

High molecular weight, high functionality diamino telechelic polybutadienes (TPBs) were synthesized by ring-opening metathesis polymerization (ROMP) of 1,5-cyclooctadiene (COD) in the presence of a chain transfer agent, 1,8-dicyano-4-octene, followed by lithium aluminum hydride reduction. Melt coupling of diamino TPB with anhydride-terminated polystyrene (PS-anh) resulted in the formation of styrene-butadiene-styrene (SBS) triblock copolymers; ca. 80% maximum conversion of PS-anh was achieved within 30 s. The results from SAXS, TEM, and rheological measurements of the coupling products confirmed the formation of SBS triblock copolymers having lamellar morphology. A fluorescent-labeled PS-anh was used to study the coupling kinetics by diluting the reactants by the addition of non-functional PS.     

复合胺改性尼龙6的动态流变性能研究

在己内酰胺水解聚合时加入一定量的复合受阻胺，合成出含有复合胺的改性尼龙6树脂，研究了复合胺对尼龙6熔体的动态流变性能的影响。实验表明：随着剪切频率的增加，尼龙6熔体的复数粘度减小、储能模量和损耗模量均增大；但由于复合胺的加入，在尼龙6大分子链上引入了空间位阻基团，复合胺改性尼龙6熔体的复数粘度、储能模量及损耗模量均比未改性样增大；改性前后尼龙6的损耗因子均随剪切频率的增加呈现先增加后减小的变化趋势，在频率为18 rad／s的位置出现极大值——内耗峰，但改性尼龙6的峰值更大；改性前后尼龙熔体的lgG′～lgG″曲线均在对角线右下方，随复合胺的加入，曲线向右下方位移增大，熔体的粘性响应更明显。     

胺对镍系催化了二烯聚合规律的影响

以二乙胺为例研究了胺对Ｎｉ（ｎａｐｈ）２－Ａｌ（－Ｂｕ）３－ＢＦ３·ＯＥｔ２＋ｎ—Ｃ８Ｈ１７ＯＨ（简称Ｎｉ－Ａｌ－Ｂ＋ＲＯＨ）和Ｎｉ（ｎａｐｈ）２－Ａｌ（ｉ－Ｂｕ）３－ＢＦ３·ＯＥｔ２＋ＣＨ３ＣＯＯＣ４Ｈ９（简称Ｎｉ—Ａｌ—Ｂ＋ＢＡ）两体系聚合活性和聚合物分子量的影响，并与Ｎｉ—Ａｌ—Ｂ体系进行了对比．考察了通常条件下肢的允许含量，讨论了有胺存在时Ｎｉ／Ｂｄ、Ａｌ／Ｎｉ、Ａｌ／Ｂ摩尔比的变化对聚合规律的影响。结果表明：胺的含量高于２０ｐｐｍ时将使聚合活性和分子量降低，提高催化剂用量可以抑制胺的不利影响。     

Bromine addition and successive amine substitution of mesoporous ethylenesilica: Reaction, characterizations and arsenate adsorption

Bromination and subsequent ethylenediamine substitution of the CC double bond in mesoporous ethylenesilica were carried out to explore the characteristics of this periodic mesoporous organosilica. The structures of the products (BrPMO and EDA–BrPMO, respectively) were analysed by IR, Br K-edge EXAFS and NMR spectroscopies, as well as X-ray diffraction and nitrogen adsorption. We showed (1) that the formulae of the two products that formed were [CHBrSiO_1.5]_0.45[CHSiO_1.5]_0.55 and [NH₂CH₂CH₂NHCHSiO_1.5]_0.05 [CHBrSiO_1.5]_0.40[CHSiO_1.5]_0.55, respectively, (2) that the addition of Br₂ at room temperature occurred on the CC double bonds with disturbing the framework structure, (3) that IR absorption band of CC bonds that reacted with Br₂ is significantly different from that of inactive CC bond, (4) that the length of the C–Br bond was considerably longer than in conventional alkyl bromides, and (5) that a large proportion of the ν(C–Br) band remained at the same position in the IR absorption spectrum after the ethylenediamine (EDA) substitution, while a new ν(C–Br) absorption also appeared. The mechanisms of these reactions are discussed at both the micro and mesoscopic levels.

Arsenate adsorption on EDA–BrPMO, in which the EDA is directly bound to the “surface” of the mesopores, was compared with adsorption on EDA–Pr–PMO, which was prepared by the direct synthesis of 3-chloropropyl-functionalized mesoporous ethanesilica followed by the substitution of Cl with EDA. The strength of the adsorption, as measured with the distribution coefficient, was greater for the former adsorbent than the latter. The origin of this difference was attributed to the distance between amino group and the surface.     

Cure kinetics and mechanical properties of the blend system of epoxy/diaminodiphenyl sulfone and amine terminated polyetherimide-carboxyl terminated poly(butadiene-co-acrylonitrile) block copolymer

The cure kinetics of blends of epoxy resin (4,4’-tetraglycidyl diaminodiphenyl methane; TGDDM)/curing agent (diaminodiphenyl sulfone; DDS) with ATPEI (amine terminated poly-etherimide) -CTBN (carboxyl terminated poly (butadiene-co-acrylonitrile)) block copolymer (AB type) were studied using differential scanning calorimetry under isothermal conditions to determine the reaction kinetic parameters such as activation energy and reaction constants. Final cure conversion decreased with increasing amount of AB in the blends. A diffusion controlled reaction was observed as the cure conversion increased, and the curing reaction was successfully analyzed by incorporating the diffusion control term in the rate equation for the epoxy/DDS/AB blends. The fracture toughness was improved to about 350% compared to that of the unmodified resin at 30% of AB block copolymer. This is attributed to the formation of co-continuous morphology between the epoxy phase and AB block copolymer phase. By increasing the amount of AB, the modulus of the cured blends decreased, which was due to the presence of CTBN rubbery phases.     

Reaction pathways and roles of N-alkylmorpholine in amine·alane transamination: A mechanistic study

The cost- and energy-effective regeneration of alane has attracted much attention because of its potential energy applications. Using N-alkylmorpholine·AlH₃ as intermediates, we have recently shown alane regeneration with improved yield, selectivity, and energy-efficiency. However, detailed interactions between AlH₃ and N-alkylmorpholine were not well-understood. Herein, we present spectroscopic and theoretical studies of the reaction pathways and roles of N-alkylmorpholine in transamination. Under reduced pressures, the 2:1 alane adduct (R₃N)₂·AlH₃ is initially transformed into its 1:1, unsaturated complex R₃N·AlH₃, which then forms an equilibrium with N-alkylmorpholine (L) to generate a mixed intermediate R₃N·AlH₃·L. Under the influence of vacuum and excess N-alkylmorpholine, R₃N·AlH₃·L loses an amine molecule (with higher volatility) to give L·AlH₃ as the final product. Using N-alkylpiperidine and 1,4-dioxane as models to mimic the coordination behaviors of the morpholine N and O atoms, we further showed the roles of N-alkylmorpholine in transamination, during which it formed the N-donating complex R₃N·AlH₃·^NL and, depending on steric hindrances of R₃N, the O-donating complex R₃N·AlH₃·^OL. These results highlight the effects of amine coordination modes and steric hindrances in the reactivity of their alane adducts and will provide information for the optimization of alane regeneration.     

Selective Removal of Carbon Dioxide from Wet CO2/H2 Mixtures via Facilitated Transport Membranes containing Amine Blends as Carriers

The selective separation of carbon dioxide (CO₂) from a wet gaseous mixture of CO₂/H₂ through facilitated transport membranes containing immobilized aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), ethylenediamine (EDA) and monoprotonated ethylenediamine (EDAH⁺) and their blends was experimentally investigated. The effect of CO₂ partial pressure, amine concentration, feed side pressure and amine species on the CO₂ and H₂ permeances were studied. The CO₂ permeability through amine solution membranes decreased with increasing CO₂ feed partial pressure but the H₂ permeance was almost independent of the H₂ partial pressure. A comparison of experimental results showed that single or blended amines with low viscosity and a moderate equilibrium constant, i.e., large forward and reverse reaction rate of CO₂‐amine, are suitable for effective separation of CO₂. The permeability of CO₂ generally increased with an increase in amine concentration, although this increase may be compromised by the salting out effect and decrease in diffusivities of species. The results obtained indicated that CO₂ permeance across a variety of amines are in the order of DEA (2 M) > MD (2 M) > MD (1 M) > MEA (2 M) > MEA (4 M) > MD (4 M) > DEA (1 M) > DEA (4 M) > MEA (1 M) for various concentrations of MEA + DEA blend and are in the order of EDAH⁺ (2 M) > DEA (2 M) > MH (2 M) > DH (2 M) > ED (2 M) > EDA (2 M) > MEA (2 M) for various blends of amine.     

Synthesis and Characteristics of Dodecyl Isopropylolamine and Derived Surfactants

Dodecyl isopropylolamine has been synthesized on the basis of dodecylamine and propylene oxide. The structure of dodecyl isopropanolamine has been determined by X‐ray diffraction, elemental analysis, IR‐ and NMR‐spectroscopic methods. Ionic surfactants have been synthesized by interaction of dodecyl isopropylolamine with various acids (HCl, HBr, acetic and propionic) and alkyl halides (methyl iodide, ethyl bromide and n‐propyl bromide). Colloidal‐chemical parameters, petroleum‐collecting and petroleum dispersing capacities of the synthesized cationic surfactants have been studied.     

Amine-based solvent for CO2 absorption and its impact on carbon steel corrosion: A perspective review

Carbon dioxide (CO₂) is one of the commonly emitted gaseous by-products in industrial processes. While CO₂ gas is the main cause to greenhouse effect, various CO₂ capture technologies have been proposed and implemented to sequester the CO₂ before the waste gases being released into the atmosphere. One of the mature technologies for CO₂ absorption is by using amine-based solvents. In this regard, different single amine solvents or blended amine solvents have been proven for their capability to remove CO₂. However, the dissolution and reaction of CO₂ gas with the amine solvents turn the solution corrosive. Such phenomenon is undesired as it posts corrosion problem to the absorption column, which normally built of carbon steel material. Henceforth, understanding the behaviour of different amine-based solvents in absorbing CO₂ and its subsequent impact on carbon steel corrosion is very significant. In this review article, we will outline some of the more commonly used solvents and their respective advantages and disadvantages, motivating further investigation into the corrosion tendency. Meanwhile, existing gaps in this research area are discussed for future investigation.