Aleš Ház

Valorisation of softwood bark through extraction of utilizable chemicals. A review

Softwood bark is an important source for producing chemicals and materials as well as bioenergy. Extraction is regarded as a key technology for obtaining chemicals in general, and valorizing bark as a source of such chemicals in particular. In this paper, properties of 237 compounds identified in various studies dealing with extraction of softwood bark were described. Finally, some challenges and perspectives on the production of chemicals from bark are discussed.

Comparison of Different Methods for Extraction from Lavender: Yield and Chemical Composition

A comparative study of accelerated solvent extraction (ASE) with two conventional volatile isolation methods including traditional steam distillation and Soxhlet extraction was performed on lavender. ASE was carried out by butanol (polar protic solvent) or dichloromethane (nonpolar solvent) and the temperature was 120°C. Separation and identification of the components was carried out by GC/MS. The main components of the analysed samples were Linalool (14.79%), α-Terpineol (4.42%), Linalool oxide (furanoid) (2.92%), cis-linalyl oxide (2.8%), α-Bisabolol (1.86%) and Octacosane (1.56%) for steam distillation; for ASE (dichlormethane): β-Terpineol (2.06%), Linalyl anthranilate (1.82%), Largeracetal (1.82%), Eucalyptol (1.74%), Linalool (1.73%), Coumarine (1.28%) and Caryophylene oxide (1.08%); for ASE (butanol): Lageracetal (8.29%), Octacosane (1.75%), Eucalyptol (1.05%) and Caryophyllene oxide (1.02%) and for Soxhlet (butanol): Largeracetal (11.42%), Linalool (3.36%), Coumarine (0.83%) and Eucalyptol (0.74%). The study has shown that ASE is a fast and environmentally sustainable technique, using butanol and dichloromethane as solvent for the extraction of extractive compounds from lavender.

Composition of fatty acids and tocopherols in peels, seeds and leaves of Sea buckthorn

Abstract Peels, seeds and leaves of the Sea buckthorn were extracted by methanol and chloroform and characterized in terms of the fatty acids (FA) and tocopherol composition. All morphological parts of Sea buckthorn contained these biologically active compounds useful in medicine, pharmacology, human nutrition and cosmetics. The highest amount of α-tocopherol was found in peels (1103 mg kg-1). The lowest content of α-tocopherol was found in leaves (659 mg kg-1). Delta-tocopherol was found in higher amount in peels 1757 mg kg-1. Seeds contained 95 mg kg-1 of delta-tocopherols. Gamma-tocopherol was found in seeds (459 mg kg-1), peels (188 mg kg-1) and in leaves (587 mg kg-1). β-tocopherol was present only in seeds (171 mg kg-1). Unsaturated fatty acids were dominant in all morphological parts of Sea buckthorn. The highest amounts of unsaturated fatty acids (92 rel. %) were determined in seeds. Dominant fatty acids of seeds were linoleic acid (37 %), α-linolenic acid (30 %) and vaccenic acid (20 %). Leaves were rich in α-linolenic acid (51 %). Dominant fatty acids of peels were oleic acid (16 %), palmitic acid (33 %) and palmitoleic acid (29 %).

Deep Eutectic Solvents as Medium for Pretreatment of Biomass

In the field of green chemistry is the study of new solvent systems the great challenge. Deep eutectic solvents (DESs) represent the principles of green chemistry. Currently are preferred these new types of chemicals suitable for the selective removal of extractives, lignin or polysaccharides from biomass. Biomass is selectively treated to the individual fractions, of which is possible with following purification to obtain products in higher yields and purity. In this work are describes various deep eutectic solvents, which can be used for pretreatment of biomass.

Use of ZSM-5 catalyst in deoxygenation of waste cooking oil

This study investigated the potential use of waste cooking oil (WCO) in the production of engine fuels and valuable chemicals via catalytic cracking. WCO was processed in its pure form and in a mixture with hydrotreated vacuum gas oil (HVGO). Catalytic cracking experiments were performed using a microactivity test (MAT) (simulation of the fluid catalytic cracking environment). In cracking over the standard fluid catalytic cracking equilibrium catalyst (FCC-ECAT), the oxygen contained in the feed was consumed in the formation of CO and CO2, water and into oxygenated organic compounds (phenolics, esters, carboxylic acids, etc.), which were found in the organic phase of the liquid product. In order to remove the unwanted organic oxygenates, the catalytic system based on pure FCC-ECAT was modified by addition of the ZSM-5-based FCC catalyst. By using the mixture containing FCC-ECAT and 10 mass % of FCC-ZSM-5, it was possible to reduce the amount of organic oxygenates to almost the feasible minimum when cracking pure WCO. The effect of the catalyst mixture on cracking the feed mixture of the vacuum gas oil with 10 vol. % of WCO was manifested in the practically zero formation of organic oxygenates and in a gasoline yield comparable with vacuum gas oil (VGO) cracking.

Antibacterial and antifungal activity of phytosterols and methyl dehydroabietate of Norway spruce bark extracts

The current study focuses on the analysis of in vitro biological activity of extract from bark of Norway spruce (Picea Abies), which can find potential application in food and cosmetic industry and pharmacology. Milled bark was subjected to Soxhlet extraction and supercritical fluid extraction to obtain two ethanol extracts. These extracts were further used to obtain their pre-extracts to n-hexane. It was investigated whether beta-sitosterol exhibits bacteriostatic activity necessary to observe antimicrobial and antifungal activity of methyl dehydroabiatate. This synergic effect and bacteriostatic activity of beta-sitosterol have not been previously reported. The greatest inhibition zone of n-hexane pre-extracts was confirmed in bacterium Pseudomonas aeruginosa (0,9 - 1,5 cm) and yeast Alternaria alternata (0,7 - 1,6 cm). It is novel, the antioxidant, antimicrobial and antifungal activity of spruce bark extracts assessed in terms of food and cosmetic fortification.

Stability of the Lignins and their Potential in Production of Bioplastics

Chemical industry includes a biobased materials (sector) in which some oil-derived plastics and chemicals are replaced by new or alternative products derived, at least partially, from biomass. One of these biobased products is here today - lignin, but to fulfil its societal potential it is necessary to improve their market share while making valuable contributions to climate change mitigation. Great source of lignin is by-product (waste) from paper making industry. Lignin isolated from black liquors has a big potential to be used as a component for new bioplastic compositions. Lignosulphonates and lignin are polydispersions of different large fragments from natural tree dimensional lignin present in the wood. The kraft lignin consists of large amount of sulphur which is bonded in functional groups. Content of lignin in black liquor is in range 30 - 45% what brings potential of its isolation. In this paper we characterised and precipitated lignin with two inorganic and one organic acid (nitric, hydrochloric and tartaric acid).