Benzylation with Benzyl Alcohol Catalyzed By [ChCl][TfOH]2, a Brønsted Acidic DES with Reaction Control Self-Separation Performance

Yuan, Bing; Li, Yinglian; Fang, Yu; Li, Xiaoqiang; Xie, Congxia; Yu, Shitao

doi:10.1007/s10562-018-2403-7

Cited by 8 publications

(5 citation statements)

References 28 publications

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“…It is seen that, compared with the stretching vibration peak of −OH in TfOH (around 3560 cm –1 ), the peak in DES (around 3419 cm –1 ) has a redshift, indicating the formation of hydrogen bonds in [ChCl][TfOH] 3 . This result is consistent with that of Yuan et al To further determine the hydrogen bond interaction in DES [ChCl][TfOH] 3 , 1 H NMR of the samples were characterized in both DMSO and D 2 O. As shown in Figure b, it is seen that a low and broad peak at δ 8–12 ppm appears in 1 H NMR spectrum of [ChCl][TfOH] 3 when DMSO is used as a solvent, but this peak disappears in the solvent D 2 O. Additionally, the active hydrogen peak of −OH in TfOH at δ 7.82 ppm disappears in the solvent D 2 O, and ChCl has no this active hydrogen peak, indicating that the active hydrogen exists in DES [ChCl][TfOH] 3 , which can provide a good active center for the rearrangement reaction.…”

Section: Resultssupporting

confidence: 87%

Reusable Deep Eutectic Solvents for Clean ε-Caprolactam Synthesis under Mild Conditions

Sun

Liu

Fang

et al. 2022

ACS Sustainable Chem. Eng.

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A deep eutectic solvent (DES) with adjustable Brønsted acidity was prepared easily by choline chloride (ChCl) and trifluoromethanesulfonic acid (TfOH). The obtained DES [ChCl][TfOH] 3 exhibited great stability and excellent catalytic performance in the Beckmann rearrangement reaction as solvent and catalyst. High cyclohexanone oxime (CHO) conversion (100%) and ε-caprolactam selectivity (98.8%) were obtained under mild conditions, such as DESs 0.03 mol, CHO 0.01 mol, 100 °C for 2 h. DES [ChCl][TfOH] 3 was easily prepared, recovered, and reused simply for seven runs without noticeable loss of catalytic performance. The free energy (ΔG) and activation energy (E a ) of the reaction were −32.8 and 39.82 kJ mol −1 , respectively. And, DFT results showed that the intermolecular hydrogen bond between ChCl and TfOH improved the thermal stability of DES (the six-membered ring structure formed containing Cl and N atoms) and provided a good sponge effect for the active hydrogen catalytic center required for the reaction (the hydrogen bond formed by Cl and hydroxyl). This process offered several advantages including good yields, short reaction times, and easy catalyst recoveries and makes the DES catalytic system a potentially practical procedure for Beckmann rearrangement.

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Section: Resultssupporting

confidence: 87%

Reusable Deep Eutectic Solvents for Clean ε-Caprolactam Synthesis under Mild Conditions

Sun

Liu

Fang

et al. 2022

ACS Sustainable Chem. Eng.

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“…As can be seen from Fourier transform infrared (FT-IR) spectra in Figure 1A, 3467 cm −1 is the stretching vibration of N−H or − OH in urea, and 1149 cm −1 is the stretching vibration of C−N. As the urea content decreases, the 3467 cm −1 characteristic peak shows different degrees of red shift, indicating the formation of a hydrogen bond network in DESs, which is consistent with the findings of Yuan et al 24 There is no significant change in the characteristic peak of the FT-IR spectra of DESs which is reused six times, indicating that the characteristic structure of the reused DESs did not change.…”

Section: Infrared Characterization Results Of Samplessupporting

confidence: 89%

Application of Reaction-Extraction Coupling Technology: Highly Efficient Preparation of ε-Caprolactam over a Deep Eutectic Solvent under Mild Reaction Conditions

Wang,

Jiang,

Shi

et al. 2024

ACS Sustainable Chem. Eng.

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A coupling reaction-extraction technology was developed to produce ε-caprolactam over a Cr-based deep eutectic solvent (DES). The used DES, prepared by simple mixing and reacting under mild reaction conditions using CrCl 3 and urea, had adjustable Lewis acid property and excellent coordination ability enchanced by the hydrogen bonding microenvironment. High cyclohexanone oxime (CHO) conversion (100%) and ε-caprolactam selectivity (98.7%) were obtained under mild conditions, such as DESs 2.5 mmol, CHO 1 mmol, and 80 °C for 4 h. DES [CrCl 3 ] 2 [Urea] was easily prepared, recovered, and reused simply for six runs without noticeable loss of catalytic performance. The activation energy (E a ) of the reaction was 45.70 kJ mol −1 , attributed to the excellent coordination ability of DES [CrCl 3 ] 2 [Urea]. Meanwhile, the application of coupling reaction-extraction technology enabled the real-time separation of the product ε-caprolactam from the DES catalyst phase during the reaction process, thereby avoiding its further side reactions and improving its selectivity. Additionally, DES [CrCl 3 ] 2 [Urea] had good reusability and general applicability for the rearrangement reaction. This study provided a facile, intriguing, and scalable approach to the highly efficient preparation of ε-caprolactam.

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“…4 [10], rare earth (III) (OSO 2 C 8 F 17 ) 3 [14] zeolites [15][16][17], [19,20], 12-tungstophosphoric acid [21], I 2 [22] IrCp* complexes [23], MoO 6 [24], NaHSO 4 /SiO 2 [25], Ph 3 P(OTf) 2 [26], Fe(III)-porphyrin [27] BF 3 -H 2 O [28], Hf 0.5 [TEAPS] PW 12 O 40 [29], choline chloride-(TfOH) 2 [30], and B(C 6 F 5 ) 3 [31]. Our method is eco-friendly as the only by-product is water and the TFA can be recycled.…”

Section: Methodsmentioning

confidence: 99%

Trifluoroacetic Acid-Promoted Friedel-Crafts Aromatic Alkylation with Benzyl Alcohols

Gribble

2018

BJSTR

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Benzylation with Benzyl Alcohol Catalyzed By [ChCl][TfOH]2, a Brønsted Acidic DES with Reaction Control Self-Separation Performance

Cited by 8 publications

References 28 publications

Reusable Deep Eutectic Solvents for Clean ε-Caprolactam Synthesis under Mild Conditions

Reusable Deep Eutectic Solvents for Clean ε-Caprolactam Synthesis under Mild Conditions

Application of Reaction-Extraction Coupling Technology: Highly Efficient Preparation of ε-Caprolactam over a Deep Eutectic Solvent under Mild Reaction Conditions

Trifluoroacetic Acid-Promoted Friedel-Crafts Aromatic Alkylation with Benzyl Alcohols

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