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Reconstructing the Knoevenagel condensation g the Knoevenagel condensation Author Ouassim L’Karkouri Academy of Technology for Health and Environment Avans Hogeschool, Breda Jack van Schijndel Abstract Green chemistry is becoming an important factor with chemical processes. The Knoevenagel condensation is a variant of the aldol condensation, the aldol condelsation is one of the oldest chemical reaction to form a carbon -carbon bond. The aldol condensation can either be base or acid catalysed. The Knoevenagel condensation is the same reaction as the aldol condensation but with amines as catalysis[1]. However in the present day the Knoevenagel condensation is documented in literature with the same mechanism as the aldol condensation[2]. We think that this is partially incorrect, the amines used in the Knoevenagel condensation act as organocatalyst instead as a base (figure 1). The goal of this research is to determine the catalytic intermediate and its catalytic activity of ammonium, 2 -aminoethanol and piperidine in the Knoevenagel condensation of benzaldehyde, 4-nitrobenzaldehyde and 4-methoxybenzaldehyde with diethylmalonate. We hypothesise that the catalytic intermediate of ammonium and 2 -aminoethanol a schiff’s base is and piperidine a bis aminal is. The Schiff’s base intermediates were created by letting benzaldehyde react with ammonium and 2- aminoethanol at 40°C which results in a condensation. the bis aminal intermediate was created by letting benzaldehyde react with piperidine at normal conditions. These intermediates are analysed with FT-IR, 1 H-NMR and mel The catalytic activity of these intermediates is determined by letting benzaldehyde react with diethylmalonate with 2,5% m/m % catalytic intermediate at 80°C and 100°C. the yield is monitored per time unit with RP-HPLC. Keywords: Aldol condensation, Knoevenagel condensation, catalys t, Schiff’s base, Bis-aminal Table of content Figure 1: proposed knoevenagel condensation path with ammonium. [1] E. Knoevenagel, '"Condensation von Malonsäure mit aromatischen Aldehyden durch Ammoniak und Amine," Berichte der deutschen chemischen Gesellschaft, vol. 31, no. 3, pp. 2596 -2619. [2] A.C.O. Hann and A. Lapworth, '"VII.-Optically active esters of small beta]-ketonic and small beta]- aldehydic acids. Part IV. Condensation of aldehydes with menthyl acetoacetate," J.Chem.Soc., Trans., vol. 85, no. 0, pp. 46-56. 40
Isolation of catalytic intermediates and acetylated analogs from amines and aromatic aldehydes Green Knoevenagel Condensation Author Alexandros Politis ATGM Academie voor Technologie Gezondheid en Milieu Avans Hogeschool, Breda Avans Hogeschool, Jack van Schijndel Jack van Schijndel Abstract The formation of carbon-carbon bonds is always sought after in organic chemistry. In The Knoevenagel Condensation carbon-carbon bonds are created with the use of large amounts of basic solvents such as pyridine. [1] The difficult part in this is creating them in a greener way then is currently being done. The Green Knoevenagel Condensation introduces the use of a catalytic amount of organocatalyst and no solvent. It creates a catalytic intermediate (Schiff -base) which in turn catalyzes the reaction. The goal of this study is to synthesize catalytic intermediates, shown in Figure 1, and acetylated analogs from ammonia, benzylamine, piperidine together with benzaldehyde, 2 -hydroxy-benzaldehyde, 3-hydroxybenzaldehyde and 4-hydroxy-benzaldehyde. [2] Subsequently the catalytic activity of these catalytic intermediates will be determined relative to each other using a HPLC analysis. First, the hydroxy-benzaldehydes are acetylated using acetic anhydride and sodium acetate. This is being done to protect them from any reactions that may occur with the added amine. After this the benzaldehyde and the amine of choice are added together in their respective ratios. Mol sieves are being used to absorb water from the reaction, as water retains equilibrium and keeps the Schiff -base from being able to be isolated. After this reaction the Schiff-base is purified and analyzed. Last, (hydroxy)benzaldehyde and dibenzyl malonate are added 1:1 together with 5 mol% catalytic intermediate. The reaction is followed using TLC and conversion is determined on HPLC. Keywords: Knoevenagel Condensation, Organocatalyst, catalytic intermediate, Schiff-base Table of content Figure 1 Benzaldehyde and amines forming catalytic intermediates and reacting with dibenzyl malonate. [1] Rao, B. V. S. K, Vijayalakshmi P, Subbarao R. Synthesis of long-chain €-3-alkenoic acids by the Knoevenagel condensation of aliphatic aldehydes with malonic acid. Journal of the American Oil Chemist’ Society. 1933;70(3):297-299. doi: 10.1007/BF02545311 [2] G. Jones. Organic reactions the Knoevenagel condensation. 41
Page 1 and 2: Book of Abstracts Poster presentati
Page 3 and 4: Avans University of Applied Science
Page 5 and 6: Collaborations 5
Page 7 and 8: Preface Dear reader, We present her
Page 9 and 10: Index SPOC1 13 Tutor: Nishant Sewgo
Page 11 and 12: Group index SPOC1 The inhibition of
Page 13 and 14: The inhibition of the Pseudomonas A
Page 15 and 16: Synthesis of a surface-active RAFT-
Page 17 and 18: Synthesis for a building block for
Page 19 and 20: 19
Page 21 and 22: Group index SPOC2 In situ catalysed
Page 23 and 24: Book of abstracts SPOC 2018 3,4-uns
Page 25 and 26: Determination of activation energie
Page 27 and 28: Book of abstracts SPOC 2018 Synthes
Page 29 and 30: Group index SPOC3 Decarboxylation o
Page 31 and 32: Decarboxylation of ferulic acid to
Page 37 and 38: Group index SPOC4 The kinetics of t
Page 39: The kinetics of the Knoevenagel con
Page 43 and 44: Chemical recycling to Oxazolines Au
Page 45 and 46: Group index SPOC5 Molecular Imprint
Page 47 and 48: Taxus extract Molecular Imprinted P
Page 49 and 50: MIP synthesis of 4-vinylpyridine Au
Page 51 and 52: Biobased Block-Copolymers due ATRP
Page 53 and 54: 53
Page 55 and 56: Group index SPOC6 Synthesis of Beta
Page 57 and 58: Synthesis of Beta-lactam in three s
Page 59 and 60: Isoxazoline ring opening by TBAT to
Page 61 and 62: Synthesis of a ligand for a synthet
Page 63 and 64: Group index SPOC7 Synthesis of a te
Page 67 and 68: Synthesis of a terpyridine ligand f
Page 69 and 70: Synthesis of peptides for IR foldin
Page 71 and 72: Peptide synthesis for unravelling p
Page 73 and 74: Dear reader, Acknowledgement s Afte

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