Characterization of Brauns’ lignin from fresh and vacuum-dried birch (Betula pendula) wood

Hiltunen, Eveliina; Alvila, Leila; Pakkanen, Tuula T.

doi:10.1007/s00226-006-0072-y

Cited by 25 publications

(11 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…ethanol extract contained slightly more beOe4 structures than milled-wood lignin. In Brauns' lignin from birch, the beOe4 structures were found to account for 50% of the aromatic content (on the basis of 1H NMR spectroscopy) (Hiltunen et al, 2006), which is a considerably higher proportion than in our HMM material from spruce knotwood.…”

Section: Thm-gc-ms Analysis the Thm-gc-ms Analysis Showedmentioning

confidence: 96%

“…It was suggested that Brauns' lignin from softwoods consists partly or entirely of oligolignans because, among other things, the degradation products of isolated protolignins are very similar to the lignans identified in L. leptolepis (Sakakibara et al, 1987;Hiltunen et al, 2006). Brauns' lignin from hardwood (birch), was shown to consist of guaiacyl-and syringylpropane units mainly with beOe4 and beb side chain structures (Hiltunen et al, 2006). The oligolignan material isolated in the present study from a Norway spruce knotwood ethanol extract may also be classified as some kind of Brauns' lignin.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chemical characterization of high-molar-mass fractions in a Norway spruce knotwood ethanol extract

2016

View full text Add to dashboard Cite

Section: Thm-gc-ms Analysis the Thm-gc-ms Analysis Showedmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Chemical characterization of high-molar-mass fractions in a Norway spruce knotwood ethanol extract

2016

View full text Add to dashboard Cite

“…[97]. Hiltunen et al [98] investigated the influence of Brauns' lignin on the color change of birch that takes place during vacuum drying and determined that Brauns' lignin underwent a chemical change during vacuum drying of the wood and that this change may have affected the color of the wood [95]. Möttönen and Luostarinen determined that the plantation Betula pendula color was consistently darker for vacuum-dried lumber than conventionally dried lumber, which was partly explained by the relatively high initial temperatures used in vacuum drying.…”

Section: Vacuum Drying and Colormentioning

confidence: 99%

Vacuum Drying of Wood—State of the Art

Espinoza

Bond

2016

Curr Forestry Rep

View full text Add to dashboard Cite

In this paper, we review the literature published on vacuum drying of wood. Vacuum drying is not a new technology, and its use for drying wood has been suggested since the early 1900s. Technologies for vacuum drying of wood can be classified by the heating method used. In this paper, we define vacuum-drying methods in four groups: conductive heating vacuum, cyclic vacuum, superheated steam vacuum, and dielectric vacuum. Advantages of drying wood below atmospheric pressure are the ability to dry at lower temperatures (and thus lower the probability of developing some drying defects), greatly reduced drying times, color preservation, greater energy efficiency, better control of volatile organic compound emissions, and the ability to dry very large cross sections. Some characteristics that differentiate vacuum from conventional drying are that in vacuum the primary driving force is the total pressure difference, the prevailing moisture transfer mechanism is water vapor bulk flow, and there is greater water migration in the longitudinal direction. While past research has focused on increasing the understanding of the fundamental mechanisms for vacuum drying and applications to specific industries and species, more recent efforts have concentrated on improving existing methods, for example, by improving moisture control and the use of pretreatments to improve drying quality.

show abstract

“…Phenolics were abundant in ray parenchyma and tended to darken at elevated temperatures, less in conventional drying than in vacuum drying [78]. In two other studies, the discoloration of the surfaces of European white birch during vacuum drying was investigated, and it was determined that the yellowness of the surface layer was associated with the accumulation of low-molecular-weight phenolic extractives, and the redness with Brauns' lignin and possibly proanthocyanidins [79,80]. For vacuum drying of oak (Quercus spp.…”

Section: Effect Of Drying On Colormentioning

confidence: 99%

A Decade of Improved Lumber Drying Technology

Bond

Espinoza

2016

Curr Forestry Rep

View full text Add to dashboard Cite

In this paper, we comprehensively review the relevant literature published from 2005 to 2016, focused on lumber drying and provide a summary of where we feel future research will focus. Drying is a critical part of most wood products manufacturing process, and the methods used and proper control are key to achieving the appropriate production level, quality, and costs. While a combination of drying methods may be used, most lumber is dried in a kiln at some point in the process. The most common commercial kilns can be classified as conventional, high temperature, and vacuum; however, there continues to be some interest in solar and compression drying. While no new drying technologies have been proposed, work has continued on improving the existing methods. Control of the drying process varies with the type of kiln used, the species being dried and the temperatures used in the process; however, it usually involves some type of measurement of the moisture content of the wood being dried. The development of new methods for controlling the drying process focuses on new ways to measure moisture content or moisture content variation, temperature drop across the load, and drying stresses. While wood quality can be defined differently by its various users, for example, industrial or end users, certain aspects of quality remain constant across these groups, such as minimizing warp, checks, and splits, and discoloration, and maintaining or enhancing mechanical properties. New schedules have been proposed to increase drying rate and improve drying quality. Methods to reduce drying defects and improve its quality have focused mainly on mechanical restraint to prevent warp, better understanding of defect formation, and pre-treatments to speed up the drying process or reduce final moisture content variation. Finally, concerns regarding the environmental impacts of wood drying, most importantly the high energy demands and emissions, have increased in importance as concerns about sustainability and health issues become more mainstream.

show abstract

Characterization of Brauns’ lignin from fresh and vacuum-dried birch (Betula pendula) wood

Cited by 25 publications

References 17 publications

Chemical characterization of high-molar-mass fractions in a Norway spruce knotwood ethanol extract

Chemical characterization of high-molar-mass fractions in a Norway spruce knotwood ethanol extract

Vacuum Drying of Wood—State of the Art

A Decade of Improved Lumber Drying Technology

Contact Info

Product

Resources

About