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Practical tests BASF and the ITCF have jointly carried out for more than a year have shown that the efficiency of the production process can be greatly enhanced by the use of ionic liquids. This is because in ionic liquids, cellulose shows clearly better results for dissolving behavior and technically useful concentrations. “Cellulose fibers produced by means of ionic liquids have already now properties comparable to those of conventionally made fibers,” said Dr. Eric Uerdingen of the New Business Development team within BASF’s Intermediates division.
Around the globe, most cellulose fibers are manufactured from so-called dissolving pulp by means of the viscose process. Although this technology has been improved continuously in the past decades, it consumes more than two metric tons of chemical additives and considerable fresh water volumes per metric ton of cellulose fiber made, requiring major waste water treatment efforts. In contrast to this, the ionic liquids used as solvent can be almost entirely recycled. This also applies to the water required in fiber spinning. In addition to this, additive consumption drops significantly.
“Together with Dr. Klemens Massonne’s group at BASF’s Chemicals Research and Engineering competence center, we are developing the most suitable ionic liquids,” said ITCF researcher Dr. Frank Hermanutz, adding: “With its broad range of ionic liquids, BASF is the ideal partner.” Reconditioning and reuse of ionic liquids as well as the development of customized processes also figure on the development agenda. Uerdingen explained: “We have teamed up with ITCF, who have extensive fiber manufacturing experience, to develop this new technology and practical processes for fiber manufacturers. To design processes that respond to practical requirements, we now seek to co-operate closely with fiber manufacturers.”
Since late last year BASF has also been collaborating with the University of Alabama (UoA) in the United States. This collaborative endeavor focuses on fundamental cellulose processing research with a view to expanding the use of renewable resources.
Occurring at a volume of some 700 billion tons, cellulose is the earth’s most widespread natural organic chemical and, thus, highly important as a biorenewable resource. Even out of the 40 billion tons nature renews every year, only 0.1 billion tons are used as feedstock for further processing.
A more intensive exploitation of cellulose as a biorenewable feedstock has to date been prevented by the lack of a suitable solvent that can be used in chemical processes. Now, the use of ionic liquids for the first time permits a simple production of cellulose solutions at concentrations that are technically attractive. This new technology therefore opens up great potential for cellulose processing.
BASF looks back on some five years of experience in the fairly recent field of ionic liquids, both in manufacturing these materials and in their full-scale industrial use. At its Ludwigshafen site, the company has for some years been running the first large-scale industrial process worldwide that uses ionic liquids. This process allows fast and simple removal of acids from reaction mixtures. The reaction of an acid with a base results in a liquid salt instead of solid crystals, which frequently cause process problems in production. Reliance on ionic liquids does away with time-consuming and expensive filtration. These liquids can be easily separated from the desired products, like oil from water, and can also be reused. 1 Methylimidazol, which replaces other bases used as additives, additionally acts as a catalyst, thus speeding up the reaction considerably. An eco-efficiency analysis has confirmed that the use of BASF’s BasilTM process for scavenging acids in the chemical synthesis of phosphorus compounds offers significant advantages over the conventional system. Compared to amines, which have been used traditionally in this type of reaction, the BASF process based on 1 methylimidazole is less cost-intensive and at the same time easier on the environment. The new process for synthesizing phosphorus compounds, which are used as chemical building blocks to produce photoinitiators in UV-curable coatings, reliably avoids a number of problems encountered to date: Stability and product yield improve, and the process is less laborious.>.
Source: BASF AG
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