共查询到17条相似文献,搜索用时 171 毫秒
1.
钙基负载型固体碱催化酯交换反应活性评价 总被引:4,自引:0,他引:4
动植物油脂与醇通过酯交换反应制备生物柴油,目前,工业上一般采用NaOH、KOH、NaOCH,等均相催化剂。均相催化剂的缺点是产品后处理复杂,产生大量含碱含油工业废水。而非均相固体碱催化酯交换反应,产品与催化剂分离容易,产品不需要水洗,避免了大量废液的排放。采用非均相固体碱制备生物柴油的文献报道较多,但固体碱的碱中心数、碱中心强度对酯交换反应影响的报道较少。本研究制备了钙基负载型固体碱催化剂,重点研究钙基负载型固体碱的制备工艺条件对碱强度、碱量分布的影响,考察碱强度、碱量分布对催化菜籽油与甲醇的酯交换反应制备生物柴油转化率的影响。 相似文献
2.
氧化硅负载的固体碱上乙醛的气相缩合反应 总被引:1,自引:0,他引:1
在氧化硅负载的含碱金属固体碱催化剂上乙醛能有效地缩合生成丁烯醛及丁烯醇,反应具有中等转化率,较好的造反性,和稳定性,考究了不同反应条件对催化性能的影响,并对可能的反应生相进行了探讨。 相似文献
3.
4.
以共沉淀法制备了一系列不同价态过渡金属(Fe、Cu、Zr)改性的Mg-Al固体碱催化剂,考察了其对于甲醇与碳酸丙烯酯(PC)酯交换合成碳酸二甲酯的反应性能。采用XRD、N_2吸附-脱附、FT-IR、XPS、CO_2-TPD等手段对催化剂的物理化学性质进行了表征。结果表明,催化剂的碱强度、碱密度是影响催化活性的主要因素,不同价态过渡金属的加入可以调控Mg-Al固体催化剂的碱性。在考察的催化剂中,FeMgAl催化剂具有最高的表面碱密度,因此,表现出最好的催化性能。在温度为65℃、时间为4 h、甲醇与PC物质的量比为10∶1、催化剂用量为4%的反应条件下,PC转化率可达66.2%。 相似文献
5.
催化裂化汽油固体碱预碱洗的研究:负载固体碱对硫化氢的吸附过?… 总被引:5,自引:0,他引:5
以活性炭为载体,碱金属化合物为活性组分,制备出负载固体碱,对其吸附硫化氢性能进行了研究。结果表明,此类固体碱吸附硫化氢能力较强,在固体碱孔外主要进行化学吸附,在固体碱孔内以物理吸附为主,化学吸附和物理吸附能力分别与固体碱、固体碱孔内所负载活性组分的量有关。 相似文献
6.
二甲胺乙基膦酸钡新型固体碱催化剂的研究 总被引:6,自引:0,他引:6
首次用二甲胺乙基膦酸与氯化钡在碱性溶液中制得二甲脘乙基膦酸钡载体,用5%NaOH溶液处理该载体,制得相应的固体碱,并用元素分析,IR、TG、DTA、DTG对其进行了表征,用指示剂法,测得固体碱碱强度(H-)为9.3~15.0;采用苯甲酸滴定法,测定了载体2和固体碱3在水中的游离碱量;讨论了载体制备中,驾流时间对载体2和固体碱3在水中游离碱量的影响。将固体碱用于催化Konevenagel缩合反应,产 相似文献
7.
8.
9.
10.
11.
Rupankar PairaArindam Maity Shyamal MondalSubhendu Naskar Krishnendu B. SahuPritam Saha Abhijit HazraE. Padmanaban Sukdeb BanerjeeNirup B. Mondal 《Tetrahedron letters》2011,52(14):1653-1657
Basic alumina supported solvent-free one-pot synthesis of pyridine-fused polycyclic diazepaniums was achieved under microwave irradiation. The process was successfully extended to the synthesis of pyridine-fused bicyclic imidazolidiniums and tetrahydro-pyrimidiniums and also of tri- and tetracyclic diaza-heterocycle-fused quinoliniums. The dual characteristic of basic alumina, a solid support as well as a base, was successfully employed in the current investigation. The method emerged to be an effective route in terms of product yield, reaction time, and ease of purification and most importantly for environment friendly protocols. 相似文献
12.
The enantioseparation of basic compounds represent a challenging task in modern SFC. Therefore this work is focused on development and optimization of fast SFC methods suitable for enantioseparation of 27 biologically active basic compounds of various structures. The influences of the co-solvent type as well as different mobile phase additives on retention, enantioselectivity and enantioresolution were investigated. Obtained results confirmed that the mobile phase additives, especially bases (or the mixture of base and acid), improve peak shape and enhance enantioresolution. The best results were achieved with isopropylamine or the mixture of isopropylamine and trifluoroacetic acid as additives. In addition, the effect of temperature and back pressure were evaluated to optimize the enantioseparation process. The immobilized amylose-based chiral stationary phase, i.e. tris(3,5-dimethylphenylcarbamate) derivative of amylose proved to be useful tool for the enantioseparation of a broad spectrum of chiral bases. The chromatographic conditions that yielded baseline enantioseparations of all tested compounds were discovered. The presented work can serve as a guide for simplifying the method development for enantioseparation of basic racemates in SFC. 相似文献
13.
Mohammadreza Shokouhimehr Mehdi Shahedi Asl Babak Mazinani 《Research on Chemical Intermediates》2018,44(3):1617-1626
In this study, mesoporous silica materials with tuned pores and surface areas were successfully synthesized by adjusting the amount of applied hexane and controlling the hydrothermal temperature. The synthesized silica materials were then functionalized by an amine group to produce solid base catalysts and be applicable as efficient heterogeneous base catalysts for the Henry reaction. The mesoporous silica catalysts possessing large-pores and surface area expose their active catalytic sites and thereby improve contacts with reactants fulfilling the reactions expeditiously in comparison with solid base catalysts possessing small-pores and surface area. The results indicated that the yield of the products is significantly dependent on the structure of the applied solid base catalysts. The modulated large-pore solid base catalysts presented high catalytic activity in Henry reactions and could be reused for five consecutive cycles. 相似文献
14.
The heterogeneous base-catalyzed transesterification for biodiesel synthesis has been studied intensively over the last decade.
This review classifies the solid base catalysts for transesterification into the following six categories based on Hattori’s
classification: single metal oxides, mixed metal oxides, zeolites, supported alkali/alkaline earth metals, clay minerals (hydrotalcites),
and non-oxides (organic solid bases). The catalysts in each category have acceptable catalytic activities overall, and follow
specific catalyst design rules, although not completely systematically, thereby drawing the best activity from them. In parallel,
each catalyst is not versatile and has some limitations specifically related to its catalytic structure and properties. This
review focuses on the heterogeneous base-catalyzed transesterification in terms of catalyst development, based on the published
research, especially over the last decade. 相似文献
15.
16.
Li-ion solid electrolytes, which are compatible with metallic lithium anodes, are the key component of all solid-state batteries. Recently, the garnet Li7La3Zr2O12 solid electrolyte has experienced booming development and shown great potential for its excellent overall performance. However, further understanding of its stability with lithium is required for a longer battery lifetime. In this review, latest research work on the interface between garnet-type solid electrolytes and lithium is presented, including both mechanisms governing interface stability and interface engineering methods. The development prospects and potential directions for following research are also discussed in the last section. 相似文献
17.
Parezhati Pataer Turghun Muhammad Yunusjan Turahun Wenwu Yang Sailemayi Aihebaier Muyasier Wubulikasimu Lingxin Chen 《Journal of separation science》2019,42(8):1634-1643
We describe a stoichiometric approach to the synthesis of molecularly imprinted polymers specific for auramine O. Using the stoichiometric interaction in molecular imprinting, no excess of binding sites is necessary and binding sites are only located inside the imprinted cavities. The free base of the template was obtained to facilitate the interaction with the monomers. Itaconic acid was selected as the functional monomer, and stoichiometric ratio of the interaction with the free base was investigated. The molecularly imprinted polymer preparation conditions such as cross‐linker, molar ratio, porogen were optimized as divinylbenzene, 1:2:20 and chloroform/N,N‐dimethylformamide, respectively. Under the optimum conditions, a good imprinting effect and very high selectivity were achieved. A solid‐phase extraction method was developed using the molecularly imprinted polymers as a sorbent and extraction procedure was optimized. The solid‐phase extraction method showed a high extraction recovery for auramine O in its hydrochloride form and free form compared to its analogues. The results strongly indicated that stoichiometric imprinting is an efficient method for development of high selectivity molecularly imprinted polymers for auramine O. 相似文献