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Dissolution and processing of cellulose using ionic liquids

A technology for dissolving cellulose and ionic liquid, applied in the field of dissolving cellulose, can solve the problems of no practical value and unacceptable

Inactive Publication Date: 2007-08-01
UNIVERSITY OF ALABAMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the degree of secrecy with which the molten salt system was described at the time, the discovery appeared to be a novelty with no practical value
When people did not understand ionic liquids and realized the application and value of ionic liquids as a class of solvents, this original work was not accepted by people

Method used

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  • Dissolution and processing of cellulose using ionic liquids
  • Dissolution and processing of cellulose using ionic liquids
  • Dissolution and processing of cellulose using ionic liquids

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0099] Example 1: Cellulose Dissolving

[0100] We found that the best ionic liquid for dissolving an exemplary test material, regenerated fibrous cellulose, was [C 4 mim] Cl. In the general method, fibrous cellulose (0.2 g) was placed in a glass vial of molten [C 4 mim]Cl (2 g) and heated in a domestic microwave oven with 3 x 5 second heating pulses. After each heat pulse, the vial was removed and vortexed to mix the contents before being placed back in the microwave. Optically clear viscous solutions of cellulose in ionic liquids were obtained.

[0101] Solutions of cellulose dissolved in ionic liquids at different concentrations can be prepared in this way. The viscosity of the solution increases with the increase of cellulose concentration. When the cellulose concentration reaches 25% by weight, a transparent solution can still be obtained. When the cellulose concentration is higher, an opaque viscous gel is formed. For cellulose in [C 4 The actual solubility lim...

Embodiment 2

[0104] Example 2: Dissolution of cellulose in 1,3-dialkylimidazolium salts with anions and cations functional relationship

[0105] Compared with conventional solvents, cellulose is more easily dissolved in ionic liquids at high concentrations. Screening of ionic liquids with different cations as their chloride salts. These salts include [C 6 mim]Cl and [C 8mim] Cl. It was found that the solubility of cellulose in imidazolium-based ionic liquids decreased with increasing cationic alkyl chain length.

[0106] Screens for various anions, from small hydrogen bond acceptors (Cl - ) to large noncoordinating anions (tetrafluoroborate and hexafluorophosphate) as [C 4 mim] + Salt. Anions include Cl, Br, thiocyanate, perchlorate, hexafluorophosphate and tetrafluoroborate. These results are shown in Table 1 below.

[0107] We found that ionic liquids containing anions (halogens and pseudohalogens) with strong hydrogen bond acceptors can obtain good dissolution effects. All...

Embodiment 3

[0116] Example 3: Cellulose regeneration

[0117] We have found that cellulose can be precipitated from ionic liquids by adding water. This incompatibility is the basis for the regeneration method described below.

[0118] By adding a known amount of water to the ionic liquid, then using microwave heating to carry out the dissolution process to determine the water that can still maintain the solvent properties of the ionic liquid in [C 4 mim] concentration in Cl. When the moisture content of the ionic liquid is greater than about 1% by weight (about 0.5 mole fraction of H 2 O), the solvent properties were significantly weakened, and we found that the fibrous cellulose was no longer soluble.

[0119] When a high concentration of cellulose (greater than 10% by weight) is dissolved in [C 4 mim]Cl, a solution with an optical anisotropy between that of a crossed polarizing filter and one exhibiting birefringence is obtained. The formation of liquid crystal solutions of cellu...

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Abstract

Cellulose is dissolved in an ionic liquid without derivatization, and is regenerated in a range of structural forms without requiring the use of harmful or volatile organic solvents. Cellulose solubility and the solution properties can be controlled by the selection of the ionic liquid constituents, with small cations and halide or pseudohalide anions favoring solution.

Description

[0001] This application is an invention patent with the PCT application number PCT / US02 / 31404 (the application number of which entered the national stage is 02823875.3), the application date is October 3, 2002, and the invention name is "using ionic liquid to dissolve and process cellulose" Divisional application of the application. Background technique [0002] Cellulose is the most abundant biorenewable material, and various products derived from cellulose have been used in all cultural fields from the most primitive societies to the highly developed modern technological societies. In addition to the use of unmodified cellulose-containing materials (e.g. wood, cotton), modern cellulose technology requires the extraction and processing of cellulose from primary sources using various modern chemical-industrial processes such that the obtained cellulose varies considerably small. [0003] As a raw material, cellulose and its various derivatives can replace many chemicals. For...

Claims

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Application Information

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IPC IPC(8): C08B1/00C08B16/00C08L1/02C05G5/00C08J3/09C08J3/28C08L1/06C12N11/12D01F2/02
CPCC08J3/28C08J3/096C08J2301/02Y10T428/31971C08B1/003C08L1/06Y10T428/31772C12N11/12D01F2/02C08J11/08Y02W30/62
Inventor R·P·斯瓦特罗斯基R·D·罗杰斯J·D·霍尔布雷
Owner UNIVERSITY OF ALABAMA
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