Transformation of ethanolamine to diazabicyclo [2. 2. 2] octane over MFI zeolite

Bhat, Y. S.; Das, Jagannath; Ali, Syed Saif; Bhatt, B.D.; Halgeri, A. B.

doi:10.1016/s0926-860x(96)00272-4

Cited by 8 publications

(2 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This mechanism is repeated in other publications [23][24][25]. However, such a mechanism is less probable on acidic catalysts in the absence of a metal component.…”

supporting

confidence: 60%

Side Products Formation in the Synthesis of Diazabicyclo[2.2.2]octane on Zeolite ZSM‐5

2007

View full text Add to dashboard Cite

A research investigation into the synthesis of 1, 4-diazabicyclo[2.2.2]octane from ethylendiamine over zeolite ZSM-5 was carried out. A number of side products such as alkylpyrazines, alkylpiperazines and alkyl-1, 4-diazabicyclo[2.2.2.]octanes were identified in the reaction mixture. A chemical mechanism based on elimination, condensation, cracking and proton transfer reactions was proposed for the formation of these compounds. . The preparation of DABCO from many different raw materials, e.g., piperazine and its derivatives, ethanolamines and polyethylenpolyamines, is principally described in patent literature. A number of different catalysts used, e.g., amorphous aluminosilicates synthetic or natural, SiO 2 , alumina, metal oxides and phosphates, are mentioned [1][2][3][4][5][6][7][8][9][10]. Recently, zeolites of the type ZSM-5 have been mainly used because of their high selectivity. Several patents in the use of zeolite and especially different modifications to increase the selectivity to DABCO have been published [14][15][16][17][18][19][20].In general, the synthesis of DABCO can be considered as a condensation reaction and depending on the feed raw materials, dehydration or deamination over acidic catalysts also occurs. Another main product in the synthesis is piperazine (PIP) which can also be recycled as N-(2-hydroxyethyl)piperazine (HEPIP) and N, N′-bis(2-hydroxyethyl)piperazine (BHEPIP) [21].In addition to DABCO and PIP, the reaction mixture also contains other minor products. According to the literature, these compounds are mainly pyrazines, e.g., pyrazine (PYR), methylpyrazine (MPYR), ethylpyrazine (EPYR) and 2, 3-dimethyl-pyrazine (2, 3-DMPYR), and derivatives of piperazine, e.g., Nmethylpiperazine (N-MPIP) and N-ethylpiperazine (N-EPIP).Kulkarni et al. [22] has suggested the dehydrogenation of piperazine as a possible route to pyrazines. This mechanism is repeated in other publications [23][24][25]. However, such a mechanism is less probable on acidic catalysts in the absence of a metal component. One of the reaction products of such a mechanism is hydrogen, which has never been detected over zeolite assumes in his work that the dehydrogenation of adsorbed ethylenediamine (EDA) molecules and subsequent hydrolysis to 2-aminoacetaldehyde, occurs through a series of condensation and C-alkylation reactions to form the precursor to pyrazines. This proposition is based on the work of Matsumura et al. [27] who dealt with the conversion of ethanol to acetaldehyde over a silicate at 400°C. Matsumura used a silicalite-1 catalyst that was thermally treated at 750°C. The author assumes that the terminal Si-OH groups, which are caused by the defects in the lattice, dehydrate at high temperatures and yield an oxygen bridge that is able to catalyze the dehydrogenation. Low conversions of ethanol to acetaldehyde are achieved and only partial elimination takes place. The small amounts of water produced by the elimination cause a rapid catalyst deactivation. Reichle did not use catalysts calcined at such high tem...

show abstract

“…This mechanism is repeated in other publications [23][24][25]. However, such a mechanism is less probable on acidic catalysts in the absence of a metal component.…”

supporting

confidence: 60%

Side Products Formation in the Synthesis of Diazabicyclo[2.2.2]octane on Zeolite ZSM‐5

2007

View full text Add to dashboard Cite

show abstract

“…At lower temperatures (o400 1C) the formation of pyrazine and its derivatives was low, therefore the selectivity of piperazine and DABCO was more. 89 At elevated temperatures, an increase in Lewis acidic sites is known, 90 this may be due to dehydration of Brønsted acidic sites which can lead to the formation of pyrazine derivatives. Additionally, at elevated temperatures the degradation of ethanolamine to aliphatic amines is also possible which leads to decrease in the selectivity of DABCO.…”

Section: Intermolecular Cyclization Of Ethanolamine To 14-diazabicycl...mentioning

confidence: 99%

Synthesis of N-heterocyclic compounds over zeolite molecular sieve catalysts: an approach towards green chemistry

Kandepi

Narender

2012

Catal. Sci. Technol.

View full text Add to dashboard Cite

A comparative study on the dehydration of monoethanolamine over cesium phosphate modified zeolite catalysts

Sun

Yan²,

Liu³

et al. 2008

Catalysis Communications

View full text Add to dashboard Cite

Transformation of ethanolamine to diazabicyclo [2. 2. 2] octane over MFI zeolite

Cited by 8 publications

References 2 publications

Side Products Formation in the Synthesis of Diazabicyclo[2.2.2]octane on Zeolite ZSM‐5

Side Products Formation in the Synthesis of Diazabicyclo[2.2.2]octane on Zeolite ZSM‐5

Synthesis of N-heterocyclic compounds over zeolite molecular sieve catalysts: an approach towards green chemistry

A comparative study on the dehydration of monoethanolamine over cesium phosphate modified zeolite catalysts

Contact Info

Product

Resources

About