混合胺溶液耦合CaO吸收-矿化CO2特性及矿化过程关键影响因素研究

有机胺捕集CO₂是一种有效的燃烧后碳捕集(PCC)技术,同时CO₂矿物碳酸化是一种安全和稳定封存CO₂的方法。本研究通过将两种方式结合,以MEA/MDEA混合胺溶液作为CO₂吸收剂,以CaO作为CO₂矿化原料,研究了不同混合胺溶液配比、温度、反应时间和CaO添加比例等条件下混合胺溶液耦合CaO吸收-矿化CO₂性能。结果表明,在常温常压下CaO可对MEA/MDEA溶液中吸收的CO₂进行有效矿化并同时实现MEA/MDEA溶液的再生;并且经过五次循环吸收-矿化实验后,MEA/MDEA溶液仍保持了较高的CO₂转化率(77.4%)和CO₂循环负荷(1.03 mol/L)。FT-IR和XRD表征分析表明,CaO的添加向MEA/MDEA溶液中提供了大量Ca²⁺和OH^-,可分别与溶液中的CO₃^2-/HCO₃     

N,N-二甲基正辛胺/十六烷混合体系液液相变吸收SO2

为了克服传统脱硫工艺胺法脱硫中挥发的吸收剂污染空气以及吸收剂回收过程能耗巨大的缺点,开发了一种新型液液相变有机胺混合脱硫体系.将碱性较大的吸收剂N,N-二甲基正辛胺（DMOA）与沸点较高的溶剂十六烷混合形成均相溶液.其在吸收二氧化硫（SO₂）后自动分为两相,十六烷在上相,SO₂与DMOA反应的产物位于下相.上相十六烷可以直接进行循环利用,将下相溶液中的SO₂脱除即可实现DMOA再生.经核磁共振氢谱（¹H NMR）和傅里叶红外光谱（FTIR）表征发现,SO₂和DMOA的反应产物为电子转移产物.在压力为常压、温度为20℃的条件下,混合体系最多的摩尔吸收量为2.1 mol/mol,是同等条件下混合体系CO₂摩尔吸收量的38倍.该混合体系具有良好的循环吸收性能,在常压、120℃的条件下进行解吸操作基本可以完全循环再生DMOA.这些结果表明该混合体系用于吸收SO₂具有良好的前景.     

CaO/MgO和CaO/Ca9Al6O18同时捕集CO2/SO2的循环吸收特性

以葡萄糖酸钙与葡萄糖酸镁及L-乳酸铝为前驱物,湿法制得了四种CaO/MgO和CaO/Ca₉Al₆O₁₈吸收剂,并进行了同时捕集CO₂/SO₂的实验。考察了吸收剂种类、质量配比、SO₂浓度及煅烧温度等对吸收剂吸收性能的影响。结果表明,CaO/MgO(质量比为75%/25%)吸收剂和CaO/Ca₉Al₆O₁₈(质量比为75%/25%)吸收剂分别保持了最好的吸收CO₂能力和最好的循环稳定性。SO₂严重阻碍了吸收剂对CO₂的捕集。SO₂浓度越高,吸收剂吸收CO₂能力下降的越快,但同时吸收SO₂的转化率也越高。数次循环后,总的Ca利用率开始上升,且SO₂浓度越高,上升趋势越明显。煅烧温度对CaO/MgO吸收剂和CaO/Ca₉Al₆O₁₈吸收剂循环吸收特性的影响略有不同。     

咪唑类离子液体混合物吸收CO2性能研究

结合常规离子液体和功能型离子液体在吸收CO₂方面的优势,将两类咪唑类离子液体进行混合,对其吸收CO₂的效果和再生性能进行了实验研究。结果表明,两类咪唑类离子液体混合后流动性明显改善,与CO₂接触气液传质顺畅;常规离子液体[bmim][BF₄]和[bmim][Tf₂N]与胺功能型离子液体[NH₂e-mim][BF₄]混合物较单一的离子液体吸收CO₂的量大,[bmim][CH₃CO₂]与[NH₂e-mim][BF₄]混合后较单一的[bmim][CH₃CO₂]吸收量有明显的减低;随着常规咪唑类离子液体阳离子碳链增长,混合离子液体吸收CO₂的效果变强;与胺乙基功能型离子液体混合吸收CO₂时,阴离子为[Tf₂N]的常规咪唑类离子液体要比阴离子为[BF₄]的吸收效果好;离子液体混合物吸收CO₂后经再生循环利用10次,混合物质量基本不变,循环使用后吸收CO₂性能为初始吸收性能的75%~85%。     

非胺类CO2吸收剂的研究进展

针对CO₂所带来的全球气候变化问题,本文综述了可用于捕集CO₂的非胺类吸收剂类型,认为氨基酸盐、氨基酸-碳酸钾体系、离子液体、生物型吸收剂、钙基吸收剂分别具有较高的CO₂循环吸收负荷、低毒性、热稳定性好、较优的生物相容性、钙源易获取的优势,可以弥补胺类吸收剂在吸收-解吸CO₂时腐蚀性强、再生能耗高、对环境产生二次污染等方面的不足。氨基酸盐、氨基酸-碳酸钾体系可应用于具有一定规模的CO₂捕集工业中;离子液体可应用于精准、绿色环保去除CO₂工业中;生物型吸收剂可用于规模小、CO₂浓度低的工业中;钙基吸收剂可运用于CO₂浓度高的工业中。上述吸收剂皆具有一定的工业前景。     

膜接触器 复合有机胺溶液捕集CO2(英文）

本文提出一种基于氨基酸盐的CO₂复合吸收剂,采用膜接触器 复合溶液耦合技术研究了吸收CO₂的性能,并与单一氨基酸盐溶液吸收性能进行了比较,讨论了气液流速等因素对气液出口CO₂浓度、捕集效率和总传质系数的影响,开发了一个阻力层模型预测膜接触器的总传质系数。结果表明：复合溶液的性能明显好于单一氨基酸盐溶液;与单一溶液比较,使用复合溶液,气相出口CO₂浓度较低,液相出口CO₂浓度较高,捕集效率也较高;复合溶液的总传质系数明显高于单一溶液。可以证实,在膜吸收过程中氨基酸盐基复合溶液是一高效的CO₂吸收剂。模型的预测值符合实验值。     

低共熔溶剂用于高效可逆捕集二氧化碳的研究

本文通过一步合成法合成了四种不同摩尔比的四乙基氯化胺-乙醇胺低共熔溶剂（TEAC-MEA DES）。红外光谱表征分析表明该DES是依靠氢键作用而形成的;DES的热稳定性高于MEA,且随着MEA的比例的增加而降低;对不同比例的DES进行了四次循环CO₂吸收-解吸实验,发现其吸收容量几乎不变,重复使用性能较好。在不同温度下计算了化学平衡常数,lnK对1/T线性拟合结果表明DES吸收CO₂的反应焓是负值,即吸收CO₂的反应是放热过程。该DES在吸收CO₂方面具有很大的潜力。     

CO2高效资源化利用的高温熔盐电化学技术研究

高温熔融盐具有CO₂吸收容量大、电化学窗口宽、高温下反应动力学快等特点,是利用清洁电能大规模捕集和资源化利用CO₂颇具实用化潜力的电解液体系. 本文主要介绍作者课题组近十年关于高温熔盐CO₂捕集与电化学资源化转化(MSCC-ET)技术的相关研究工作,包括熔融盐电解质对CO₂的吸收、阴极过程动力学、电解条件对产物的影响、析氧阳极、电解过程能量效率和CO₂捕获潜力,并展望了MSCC-ET技术的发展前景.     

无机盐活化剂-氨基酸盐基溶液捕集温室气体CO2

将无机盐K₃PO₄、K₂HPO₄和KH₂PO₄作为活化剂,分别添加于氨基乙酸盐溶液中,形成CO₂活化吸收剂,采用膜接触器 再生循环装置,评价和比较了氨基乙酸盐和活化吸收剂捕集CO₂的性能,研究了活化剂的浓度、气液流速等因素对总体积传质系数、传质通量和捕集率的影响。结果表明,磷酸盐活化剂在氨基乙酸盐吸收剂中,对CO₂的捕集均产生影响,活化效应存在PO₄^3－＞HPO₄^2－＞H₂PO₄^－的规律;添加少量活化剂的作用比添加较多量的活化作用大;活化吸收剂的捕集率明显大于非活化吸收剂;膜吸收流体力学状态的改变,能够改善膜接触器传质性能,增大传质通量,但增大的程度有限。     

SO2对钙基CO2吸收剂循环煅烧/碳酸化反应的影响

在循环煅烧/碳酸化反应系统中,研究了SO₂对钙基吸收剂CaCO₃捕集CO₂的影响,获得了SO₂对钙基吸收剂碳酸化特性、煅烧特性以及循环稳定性的影响规律,并结合SEM分析结果,从循环煅烧/碳酸化反应角度,分析了可能存在的原因。结果表明,钙基吸收剂吸收CO₂的能力随着循环反应次数的增加逐渐发生衰减,在SO₂影响下,这种衰减会进一步加剧,且衰减程度随着SO₂浓度的增加而增大,经过十次循环后,碳酸化转化率分别为25.5%(0%SO₂)、16.9%(0.1%SO₂)和5.2%(0.2%SO₂)。造成这种衰减加剧的主要原因是反应产生较厚的硫酸化产物层,硫酸化产物层使颗粒表面孔隙发生堵塞,阻碍了CO₂在吸收剂内部的扩散,降低了碳酸化转化率。     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.