Effect of Ionic Liquid Treatment on the Structures of Lignins in Solutions: Molecular Subunits Released from Lignin

Journal Article · Tue Jun 26 00:00:00 EDT 2012 · Langmuir

DOI:https://doi.org/10.1021/la300938b· OSTI ID:1049200

Cheng, Gang ^[1]; Kent, Michael S. ^[1]; He, Lilin ^[2]; Varanasi, Patanjali ^[1]; Dibble, Dean ^[1]; Arora, Rohit ^[3]; Deng, Kai ^[1]; Hong, Kunlun ^[4]; Melnichenko, Yuri B. ^[2]; Simmons, Blake A. ^[1]; Singh, Seema ^[1]

---

1. Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States). Deconstruction and Technology Divisions; Sandia National Lab. (SNL-CA), Livermore, CA (United States)
2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biology and Soft Matter Division
3. Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States). Deconstruction and Technology Divisions
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)

The solution structures of three types of isolated lignin—organosolv (OS), Kraft (K), and low sulfonate (LS)—before and after treatment with 1-ethyl-3-methylimidazolium acetate were studied using small-angle neutron scattering (SANS) and dynamic light scattering (DLS) over a concentration range of 0.3–2.4 wt %. The results indicate that each of these lignins is comprised of aggregates of well-defined basal subunits, the shapes and sizes of which, in D₂O and DMSO-d₆, are revealed using these techniques. LS lignin contains a substantial amount of nanometer-scale individual subunits. In aqueous solution these subunits have a well-defined elongated shape described well by ellipsoidal and cylindrical models. At low concentration the subunits are highly expanded in alkaline solution, and the effect is screened with increasing concentration. OS lignin dissolved in DMSO was found to consist of a narrow distribution of aggregates with average radius 200 ± 30 nm. K lignin in DMSO consists of aggregates with a very broad size distribution. In conclusion, after ionic liquid (IL) treatment, LS lignin subunits in alkaline solution maintained the elongated shape but were reduced in size. IL treatment of OS and K lignins led to the release of nanometer-scale subunits with well-defined size and shape.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• DOE Contract Number: AC05-00OR22725; AC02-05CH11231
• OSTI ID: 1049200
• Journal Information: Langmuir, Vol. 28, Issue 32; ISSN 0743-7463
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY