Martin Hájek

Dr. Martin Hájek

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Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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17 September 2021 in Catalysts
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MHMartin Hájek
Martin Hájek
AVAleš Vávra
Aleš Vávra
Hector de Paz CarmonaHector de Paz Carmona
Hector de Paz Carmona
JKJaroslav Kocík
Jaroslav Kocík
This review paper summarizes the current state-of-the-art of the chemical transformation of oils/fats (i.e., triacylglycerols) to the use of biofuels or bio-lubricants in the means of transport, which is a novelty. The chemical transformation is necessary to obtain products that are more usable with properties corresponding to fuels synthesized from crude oil. Two types of fuels are described—biodiesel (the mixture of methyl esters produced by transesterification) and green diesel (paraffins produced by hydrogenation of oils). Moreover, three bio-lubricant synthesis methods are described. The transformation, which is usually catalysed, depends on: (i) the type and composition of the raw material, including alcohols for biodiesel production and hydrogen for green diesel; (ii) the type of the catalyst in the case of catalysed reactions; (iii) the reaction conditions; and (iv) types of final products. The most important catalysts, especially heterogeneous and including reaction conditions, for each product are described. The properties of biodiesel and green diesel and a comparison with diesel from crude oil are also discussed.

22 January 2023 in Coatings
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MKMartin Kolář
Martin Kolář
JMJana Machotova
Jana Machotova
MHMartin Hájek
Martin Hájek
JHJan Honzíček
Jan Honzíček
THTomáš Hájek
Tomáš Hájek
ŠPŠtěpán Podzimek
Štěpán Podzimek
In this work, two bio-based raw materials, rapeseed oil and technical-grade oleic acid, were modified to yield acrylated monomers. Polymeric latexes designed for coating applications were synthesized using emulsion polymerization. Methyl methacrylate and butyl acrylate were copolymerized with various ratios of the acrylated bio-based monomers (0–20 wt.% in the monomer mixture). The polymerization with high monomer conversion and low coagulum content was successfully performed up to the content of 15 wt.% of the bio-based monomers, leading to long-term stable latexes. The asymmetric flow field flow fractionation coupled with a multi-angle light scattering detector was used to describe the molar mass distribution of the synthesized copolymers. Ultra-high molar mass fractions were detected in copolymers comprising the bio-based monomers due to the presence of multi-acrylated bio-based ingredients originating from linoleic and linolenic fatty acids. This phenomenon became more pronounced for the rapeseed oil-originated monomer. The prepared latexes comprising copolymerized bio-based monomers showed comparable or even better coating performance in terms of gloss and water resistance in comparison with the reference acrylic coating, which makes the acrylated vegetable oil-based monomers attractive for the manufacturing of sustainable water-borne materials in the coating industry.


1 August 2018 in Journal of Cleaner Production
Verified
Journal Article
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AVAleš Vávra
Aleš Vávra
MHMartin Hájek
Martin Hájek
FSFrantišek Skopal
František Skopal

8 March 2024 in Catalysts
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Luigi Di BitontoLuigi Di Bitonto
Luigi Di Bitonto
ESENRICO SCELSI
ENRICO SCELSI
Hilda Elizabeth Reynel-ÁvilaHilda Elizabeth Reynel-Ávila
Hilda Elizabeth Reynel-Ávila
DCDidilia Ileana Mendoza Castillo
Didilia Ileana Mendoza Castillo
Adrian Bonilla-PetricioletAdrian Bonilla-Petriciolet
Adrian Bonilla-Petriciolet
Carlo PastoreCarlo Pastore
Carlo Pastore
In this work, a closed-loop strategy for the management and valorization of winery waste was proposed. The exhausted pomace and grape stalks that are typically obtained from white wine industries were used as a source of simple sugars, namely, glucose and fructose, and of lignocellulosic feedstock for the preparation of selective catalysts for the 5-hydroxymethylfurfural (5-HMF) production from fructose. A novel synthetic procedure was developed for the synthesis of iron-sulfonated magnetic biochar catalysts (Fe-SMBCs). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), BET surface area, porous structure analysis and determination of total amount of acid sites were performed in order to characterize the physico-chemical properties of the synthesized systems. Then, these heterogeneous catalysts were successfully tested via the dehydration of simple sugars into 5-HMF by using methyl isobutyl ketone (MIBK) and gamma valerolactone (GVL) as co-solvents. The optimum 5-HMF yield of 40.9 ± 1.1%mol with a selectivity of 59.8 ± 2.6%mol was achieved by adopting the following optimized conditions: 0.1 g of catalyst, volume ratio of GVL to H2O = 2 to 1, 403 K, 6 h. In addition, the catalyst was easily recycled using an external magnetic field and used for at least five reaction cycles without significant loss of catalytic activity.

18 May 2023 in Renewable Energy
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MHMartin Hájek
Martin Hájek
DKDavid Kocián
David Kocián
MDMiroslav Douda
Miroslav Douda