BASF and Institute for Textile Chemistry and Chemical Fibers Improving the production of cellulose fibers

* Ionic liquids as novel solvents for cellulose
* Improved efficiency and environmental impact of cellulose fiber production

08/29/06 - Cellulose fibers can be produced in an efficient and environmentally sustainable manner by using ionic liquids. This is the result drawn by BASF and the renowned Denkendorf Institute for Textile Chemistry and Chemical Fibers (ITCF). BASF sells its ionic liquids under the brand name BasionicTM, and the corresponding processes are marketed under the name BasilTM.

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.

Practice-focused development

“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.

Cellulose: A major renewable resource

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.

Ionic Liquids from BASF are eco-efficient...

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.

... and hold promises for the future

“We believe ionic liquids hold many promises for the future,” said Dr. Matthias Maase, who works in the New Business Development unit of the BASF Intermediates operation division, “By their properties they will open up entirely new fields of application, even outside the classical chemical uses. For example, think of ionic liquids as new materials or as engineering liquids used in the mechanical and automotive industries, but also in oil and gas production, and they might even be used in the field of renewable resources. The road to use in practice is taking shape. Maase added, “We are currently talking to companies from the most varied industries all over the world who have recognized the benefits of ionic liquids and are discussing concrete applications with us.”

In 2005, BASF received the “IChemE Award” from the Institution of Chemical Engineers (IChemE), the British association of chemical and process engineers, for the development and application of its innovative ionic liquids. And in 2004 already, the company’s ionic liquids won the “Innovation Award” of the “European Chemical News” trade journal.

BASF
The operating division Intermediates of the BASF Group develops, produces and markets the world’s largest range of intermediates. The most important of the division’s more than 600 products include amines, diols, polyalcohols and acids. Among other applications, intermediates are used as starting materials for coatings, plastics, pharmaceuticals, textile fibers, detergents and crop protection agents. Innovative BASF intermediates help to improve the properties of the final product and the efficiency of production processes. The ISO 9001:2000-certified operating division Intermediates has access to plants at production sites in Europe, Asia, and the Americas. In 2005, this BASF operating division with 2,665 employees generated world sales of above 2 billion euros. For more information, go to www.basf.de/intermediates

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Klaus-Peter Rieser

BASF

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