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71.
微波常压法合成水杨酸酯 总被引:15,自引:0,他引:15
在浓硫酸催化下,采用微波常压法由水杨酸分别与正丁醇、异丁醇、正戊醇和异戊醇反应合成相应的水杨酸酯。结果表明:当水杨酸:醇:H2SO4=1:5.5:0.3(摩尔比)时,采用560W微波辐射22min,水杨酸酯的产率可达88.7% ̄96.4%,反应速度至少是常规反应的14倍。 相似文献
72.
StudiesonSolidStateReactionsofCoordinationCompounds(LXXI)──SolidStateReactionsofo-AminobenzoicAcidwithCopper(Ⅱ)AcetateandForm... 相似文献
73.
本文报道了合成1-氨基环丙烷-1-羧酸的简便而价廉的方法,即乙酰乙酸乙酯法和α-氰乙酸乙酯法;并测定了产品的结构。 相似文献
74.
75.
以2-萘甲酸为原料,经硝化,酯化,重氮化,选择性催化氢化,BOC酸酐保护等六步反应,完成了N-BOC-8氨甲基-2-萘甲酸(1a)的合成,为化合物1的合成提供了新的合成途径。 相似文献
76.
77.
Stephen G. Davies Ian A. Hunter Rebecca L. Nicholson Paul.M. Roberts Edward D. Savory Andrew D. Smith 《Tetrahedron》2004,60(35):7553-7577
α-Dibenzylamino- and α-benzyloxy- derivatives of N-acetyl-(S)-4-benzyl-5,5-dimethyloxazolidin-2-one readily undergo highly stereoselective boron mediated syn-aldol reactions with a range of aromatic and aliphatic aldehydes, generating the syn-aldol products in good to excellent yields as single diastereoisomers after purification. In the α-dibenzylamino series, deprotection of the functionalised aldol fragments to the corresponding α-amino-β-hydroxy methyl ester or α-amino-β-hydroxyaldehyde proved problematic, with a range of N- and O-protecting groups giving mixtures of products arising from endocyclic and exocyclic cleavage pathways. However, in the α-benzyloxy series, O-silyl protection of the aldol products, and subsequent DIBAL reduction gives stereoselectively the corresponding N-1′-hydroxyalkyloxazolidin-2-ones, which undergo base promoted fragmentation to the desired highly functionalised and differentially protected α,β-dihydroxyaldehydes in good yields and without loss of stereochemical integrity. 相似文献
78.
A novel mixed sol method was developed for the preparation of supported catalysts. Analyses by means of XRD and BET show that a 40%AgBiVMoO/γ-Al2O3 catalyst prepared by this method possessed high specific surface area and high dispersion of the active phase. As a result, high acrylic acid selectivity of 8.5% was obtained when the catalyst was used in the reaction of propane partial oxidation to acrylic acid in a fixed-bed reactor. 相似文献
79.
廖伟雄 《广东微量元素科学》2002,9(4):69-70
介绍了一种室温下测定水中锰的方法,经检验,其显色反应可在短时间内完成,且色泽稳定,精密度和准确度均能达到分析要求。 相似文献
80.
Vermeiren K 《Journal of chromatography. A》2005,1085(1):60-65
Since years, ion exclusion chromatography (ICE) has been the standard method to separate strong acid analyte anions from concentrated weak acid matrices such as hydrofluoric acid (HF). In this work, the commercially available IonPac ICE-AS 1 column was used to separate trace levels of chloride, nitrate, sulfate and phosphate from HF solutions at 20% (w/w). The efficiency of the separation was studied in more detail using techniques such as ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES) and ICP-mass spectrometry (ICP-MS). For 20% (w/w) HF solutions and at a water carrier flow-rate of 0.50 ml/min, the cut window was set from 8.5 to 14.5 min. Under these conditions, analyte recoveries of better than 90% were obtained for chloride, nitrate and sulfate, but only about 75% for phosphate. The HF rejection efficiency was better than 99.9%. It was found that the ICP techniques, measuring total element levels and not species, yielded significantly higher recoveries for phosphorus and sulfur compared to IC. Evidence will be given that part of the added phosphorus (approximately 15% for an addition of 10 mg PO4/kg) is present as mono-fluorophosphoric acid (H2FPO3). In the case of sulfate, the difference between IC and ICP-MS could be attributed to an important matrix effect from the residual HF concentration. 相似文献