1
|
Ai S, Huang Z, Yu W, Huang C. Efficient dissolution of cellulose in slow-cooling alkaline systems and interacting modes between alkali and urea at the molecular level. Carbohydr Res 2024; 536:109054. [PMID: 38350405 DOI: 10.1016/j.carres.2024.109054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/02/2024] [Accepted: 02/08/2024] [Indexed: 02/15/2024]
Abstract
The dissolution of microcrystalline cellulose (MCC) in a urea-NaOH system is beneficial for its mechanical processing. The apparent MCC solubility was greatly improved to 14 wt% under a slow-cooling condition with a cooling rate of -0.3 °C/min. The cooling curve or thermal history played a crucial role in the dissolution process. An exotherm (-54.7 ± 3 J/g MCC) was detected by DSC only under the slow-cooling condition, and the cryogenic dissolution of MCC was attributed to the exothermic interaction between MCC and solvent. More importantly, the low cooling rate promoted the dissolution of MCC by providing enough time for the diffusion of OH- and urea into MCC granules at higher temperatures. The Raman spectral data showed that the intramolecularly and intermolecularly hydrogen bonds in cellulose were cleaved by NaOH and urea, respectively. XPS and solid-state 13C NMR results showed that hydrogen bonds were generated after dissolution, and a dual-hydrogen-bond binding mode between urea and cellulose was confirmed by DFT calculations. Both the decrease of enthalpy and increase of entropy dominated the spontaneity of MCC dissolution, and that is the reason for the indispensability of cryogenic environment. The high apparent solubility of MCC in the slow-cooling process and the dissolution mechanism are beneficial for the studies on cellulose modification and mechanical processing.
Collapse
Affiliation(s)
- Shuo Ai
- College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China.
| | - Zhenhua Huang
- College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| | - Wanguo Yu
- College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China.
| | - Chengdu Huang
- College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou, 545006, China
| |
Collapse
|
2
|
Awasthi N, Yadav R, Kumar D. Revealing metabolic path of Ketamine catalyzed by CYP450 via quantum mechanical approach. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
3
|
Vishwkarma AK, Yadav T, Brahmachari G, Karmakar I, Yadav P, Saha S, Mahapatra C, Pandey GN, Tripathi CSP, Tripathi PK, Verma VK, Pathak A. Conformational Search and Spectroscopic Analysis of Biorelevant Molecule: 5-Chloro-2-hydroxy- N-isobutyl-3-oxo-2,3-dihydrobenzofuran-2-carboxamide. Polycycl Aromat Compd 2022. [DOI: 10.1080/10406638.2022.2135546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A. K. Vishwkarma
- Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - T. Yadav
- Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - G. Brahmachari
- Laboratory of Natural Products and Organic Synthesis, Department of Chemistry, Visva-Bharati (a Central University), Santiniketan, West Bengal, India
| | - I. Karmakar
- Laboratory of Natural Products and Organic Synthesis, Department of Chemistry, Visva-Bharati (a Central University), Santiniketan, West Bengal, India
| | - P. Yadav
- Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - S. Saha
- CSIR-Indian Institute of Chemical Biology, Kolkata, West Bengal, India
| | - C. Mahapatra
- Department of Biotechnology, National Institute of Technology Raipur, Raipur, India
| | - G. N. Pandey
- Department of Applied Physics, AIAS, Amity University, Noida, Uttar Pradesh, India
| | - C. S. P. Tripathi
- Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - P. K. Tripathi
- Department of Physics, School of Applied and Life Sciences, Uttaranchal University, Dehradun, Uttarakhand, India
| | - V. K. Verma
- Department of Physics, Keshav Mahavidyalay, University of Delhi, Delhi, India
| | - A. Pathak
- Department of Physics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| |
Collapse
|
4
|
Yadav P, Verma A, Sonker P, Sharma VP, Kumar A, Yadav T, Pal S, Saha S, Tewari A. The enthralling effect of packing on the light emission of pyridazinone based luminophore: Crystallographic, electronic absorption and computational studies. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.133513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
|