Juliusz Pernak

Poznan University of Technology, Posen, Greater Poland Voivodeship, Poland

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Publications (150)325.35 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Novel herbicidal ionic liquids (HILs) containing different anions and cations derived from ammonium esterquats were prepared by employing a simple, inexpensive pathway. The basic physicochemical properties of the synthesized salts (such as density, viscosity, refractive index, solubility and thermal stability) were determined. Additionally, their herbicidal efficacy was evaluated under greenhouse and field conditions with subsequent assessment of biodegradability and toxicity (acute oral toxicity towards rats and rainbow trout, growth inhibition test of green algae and acute immobilization test using water flea). The results of greenhouse and field experiments revealed that the herbicidal activity of HILs comprising long alkyl chains has exceeded that of commercial plant protection products. The HIL containing the di(tallowoyloxyethyl)dimethylammonium cation exhibited notable biodegradability (63% after 28 days) and various toxicity classifications depending on the tested organism: category V towards rats with LC50 > 2000 mg, category II towards fish with LC50/96 h at 10.62 mg/L, category I towards algae and daphnids with ErC50/72 h at 1.73 mg/L and EC50 at 0.28 mg/L, accordingly. These findings provide evidence that synthesis of HILs with a specifically designed structure may be successfully employed for obtaining novel, efficient and environmentally friendly plant protection agents.
    New Journal of Chemistry 05/2015; DOI:10.1039/C5NJ00609K · 3.16 Impact Factor
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    ABSTRACT: Ten sulfonylurea-based herbicidal ionic liquids (HILs) were prepared by combining the metsulfuron-methyl anion with various cation types including quaternary ammonium ([bis(2-hydroxyethyl)methyloleylammonium]+, [2-hydroxyethyltrimethylammonium]+), pyridinium ([1-dodecylpyridinium]+), piperidinium ([1-methyl-1-propylpiperidinium]+), imidazolium ([1-allyl-3-methylimidazolium]+, [1-butyl-3-methylimidazolium]+), pyrrolidinium ([1-butyl-1-methylpyrrolidinium]+), morpholinium ([4-decyl-4-methylmorpholinium]+) and phosphonium ([trihexyltetradecylphosphonium]+ and [tetrabutylphosphonium]+). Their herbicidal efficacy was studied in both greenhouse tests and field trials. Preliminary results for the greenhouse tests showed at least twice the activity for all HILs when compared to the activity of commercial Galmet 20 SG®, with HILs with phosphonium cations being the most effective. The results of two-year field studies showed significantly less enhancement of activity than observed in the greenhouse; nonetheless it was found that the herbicidal efficacy was higher than that of the commercial analog and efficacy varied depending on the plant species.
    Journal of Agricultural and Food Chemistry 03/2015; 63(13). DOI:10.1021/jf505782p · 3.11 Impact Factor
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    ABSTRACT: Tebuconazole and propiconazole were converted into salts by reaction with inorganic and organic acids. Numerous novel salts were obtained as a result, many of which could be characterized as protic ionic liquids. Their thermal stability and biological activity against fungal species Fusarium culmorum, Microdochium nivale, Sclerotinia sclerotiorum and Botrytis cinerea (in concentration range from 10 up to 1000 ppm) were assessed in the framework of this study. The evaluation revealed that high antifungal activity of the synthesized tebuconazole- and propiconazole-based salts, which may be classified as new triazole fungicides, was preserved. Physical properties of the obtained salts have changed significantly, thus creating new application possibilities of known triazole fungicides.
    RSC Advances 01/2015; 5(13). DOI:10.1039/C4RA12160K · 3.71 Impact Factor
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    ABSTRACT: Ionic liquids with dual pesticidal function were obtained using cheap, well known and commonly employed fungicides and herbicides. High activity was maintained for both the fungicide (cation) and the herbicide (anion). The obtained salts are novel phytopharmaceuticals, which may be successfully used as an alternative to conventional pesticides.
    RSC Advances 08/2014; 4(75). DOI:10.1039/C4RA04816D · 3.71 Impact Factor
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    ABSTRACT: Ammonium ionic liquids with the 4-chloro-2-methylphenoxyacetate anion were synthesized and characterized. Physicochemical properties, such as thermal stability, phase transition temperatures, viscosity, density, refractive index, as well as surface activity and herbicidal activity were determined. Improved physicochemical properties suggest a reduced environmental impact of newly formed group of herbicidal ionic liquids (HILs). HILs with a longer substituent can be characterized with better herbicidal activity in comparison with commercial products.
    Tetrahedron 08/2014; 70(32):4784-4789. DOI:10.1016/j.tet.2014.05.041 · 2.82 Impact Factor
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    ABSTRACT: Ammonium and piperidinium theophyllinate-based ILs were synthesized and characterized. Physicochemical properties, such as thermal stability, phase transition temperatures, viscosity, density, refractive index, as well as surface activity, feeding deterrence, antifungal activity and also biodegradability were determined. The synthesized theophyllinate-based ILs were surface active compounds. They exhibited insect-feeding deterrent activities. At the same time, the studied salts are also efficient fungicides and potential pesticidal ionic liquids. The obtained data suggest that certain structural modifications may increase their biodegradability in order to provide an environmentally friendly product.
    New Journal of Chemistry 06/2014; 38(7). DOI:10.1039/C4NJ00463A · 3.16 Impact Factor
  • Adam Morel, Anna M Trzeciak, Juliusz Pernak
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    ABSTRACT: Heck arylation of 2,3-dihydrofuran with iodobenzene was carried out in systems consisting of different palladium precursors (Pd2(dba)3, Pd(acac)2, PdCl2(cod), [PdCl(allyl)]2, PdCl2(PhCN)2, PdCl2(PPh3)2) and ionic liquids (CILs) with L-prolinate or L-lactate anions. All the tested CILs caused remarkable increases of the conversion values and in all of the reactions 2-phenyl-2,3-dihydrofuran (3) was obtained as the main product with a yield of up to 59.2%. The highest conversions of iodobenzene were achieved for the [PdCl(allyl)]2 precursor. Formation of Pd(0) nanoparticles, representing the resting state of the catalyst, was evidenced by TEM.
    Molecules 06/2014; 19(6):8402-8413. DOI:10.3390/molecules19068402 · 2.10 Impact Factor
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    ABSTRACT: Plant growth regulator — 2-chloroethyltrimethylammonium chloride (CCC) was converted into ionic liquid in the metathesis reaction. New forms of CCC as ILs were stable in air as well in contact with water and organic solvents. The biological action of the cation (CCC) in ILs was preserved. Type of anion determined hydrophobicity and hydrophilicity of the whole molecule and it also influenced the biological activity of the plant growth regulator. All of the investigated salts retarded growth of winter wheat stems and most of them increased yield at the same time, when compared to control and standard 2-chloroethyltrimethylammonium chloride.
    Central European Journal of Chemistry 11/2013; 11(11). DOI:10.2478/s11532-013-0309-1 · 1.33 Impact Factor
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    ABSTRACT: Herbicidal ionic liquid with dual functions has been synthesized and characterized (properties, chemical stability and biological activity). 2-Chloroethyltrimethylammonium (4-chloro-2-methylphenoxy)acetate prepared in an alkaline environment undergoes the reaction of dehydrochlorination by the E2 mechanism. This may be described as a specific instance of providing third generation ILs with high potential of application, which preserve both pesticidal properties: the herbicidal activity due to their anions and plant growth inhibition effect due to their cations.
    Tetrahedron 09/2013; 69(38):8132–8136. DOI:10.1016/j.tet.2013.07.053 · 2.82 Impact Factor
  • Applied Catalysis A General 09/2013; 466:216-223. DOI:10.1016/j.apcata.2013.06.046 · 3.67 Impact Factor
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    ABSTRACT: In this work, the application of an epoxy resin cured with ammonium ionic liquids as a support for palladium complex catalyst is reported. Supports based on epoxy resin were obtained as a result of the use of ionic liquids: didecyldimethylammonium tetrafluoroborate [d2m2am][BF4], 1-methyltheobromine tetrafluoroborate [mthb][BF4], didecyldimethylammonium theobrominate [d2m2am][thb], didecyldimethylammonium theophyllinate [d2m2am][thp] as cross-linking agents. The characterization of polymeric supports and heterogenized palladium catalysts has involved research methods like time-of-flight secondary ion mass spectrometry (TOF-SIMS), infrared spectroscopy (IR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS). The activity and stability during long-term use of the investigated catalytic systems were tested in a model Heck reaction. The influence of the type of ILs used as epoxy hardeners on the catalytic properties of epoxy-supported palladium catalysts is discussed.
    Comptes Rendus Chimie 08/2013; 16(8):752–760. DOI:10.1016/j.crci.2012.12.005 · 1.48 Impact Factor
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    ABSTRACT: New ILs containing the (2,4-dichlorophenoxy)acetate anion have been synthesized and characterized (properties, chemical and thermal stability, surface activity). Next, the possibility to use them as herbicides and plant growth regulators has been studied. The obtained ILs exhibited higher biological activity than the currently used herbicide (2,4-D salt) and plant growth regulator (CCC).
    Tetrahedron 06/2013; 69(23):4665–4669. DOI:10.1016/j.tet.2013.03.097 · 2.82 Impact Factor
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    ABSTRACT: Twenty eight new dicamba (3,6-dichloro-2-methoxybenzoic acid)-based herbicidal salts, have been synthesized and characterized in order to attempt to improve the efficacy of this widely known herbicide used to protect maize, grassland, and other cultures. The new compounds, most of which are ionic liquids by definition and three of which are solids melting above 100 degrees C, were prepared by pairing quaternary tetraalkyl-or alkoxyammonium, piperidinium, imidazolium, pyridinium, morpholinium, quinolinium, and phosphonium cations with the dicamba anion. Growth chamber and field test data suggested that ionic liquid forms of dicamba offer substantially increased efficacy which would allow less to be applied in the field. Compared to the commercial dicamba free acid product, improved physical properties were observed including higher decomposition temperatures and reduced volatilities, suggesting a potential reduction of overall environmental impact of this herbicide.
    Green Chemistry 06/2013; 15(8). DOI:10.1039/C3GC37143C · 6.85 Impact Factor
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    ABSTRACT: TiO2/N-cellulose nanocomposite wassuccessfully prepared in the (cyclohexyl)hexyldimethylammonium acetate–dimethyl sulfoxide solution. The obtained composite was characterized with various techniques like UV–Vis/DR, FTIR/DRS, X-ray diffraction, thermogravimetric analysis, DLS method and BET SSA measurements. TiO2/N-cellulose nanocomposite exhibited high UV–Vis light absorption with energy gap shifted to the visibleregion. Additive of TiO2/N photocatalyst to cellulose-IL-DMSO solution leads to obtaining the material with higher thermostability and limited photoactivity http://link.springer.com/article/10.1007/s10570-013-9906-6/fulltext.html
    Cellulose 06/2013; 20(3):1293-1300. DOI:10.1007/s10570-013-9906-6 · 3.03 Impact Factor
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    ABSTRACT: MCPA (4-chloro-2-methylphenoxy) acetic acid is a common synthetic auxin used as a herbicide. The purpose of this study was to determine the effects of four new forms of MCPA being the herbicidal ionic liquids (HILs) with MCPA as an anion and two previously known formulations (potassium–sodium salt and 2-ethylhexyl ester) on seed germination and seedling development of winter oilseed rape (Brassica napus). Rape plants are susceptible to MCPA and volunteers can be a big problem in crop rotation. Seedling fresh weight and root length were quantified, mitotic activity, as well as lipid, starch, hydrogen peroxide and polyphenol contents were assessed by light and fluorescence microscopy and the computer-aided cytophotometer. In primary roots mitotic activity was almost completely inhibited under the influence of herbicides, cell elongation zones and root hair zones were significantly reduced, and a characteristic bolded root segment formed just above a meristem. In contrast to the traditional salt formulation the new HILs were weak inducers of hydrogen peroxide synthesis, but were potent stimulators of the synthesis of phenolic compounds and storage as well as emergency substances such as lipids and starch. All tested forms of MCPA caused strong phytotoxic effect on winter rape seedlings, but the tested HILs were more effective.
    Acta Physiologiae Plantarum 03/2013; 36(3). DOI:10.1007/s11738-013-1448-x · 1.52 Impact Factor
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    ABSTRACT: New quaternary ammonium salts containing unsaturated substituents (allyl or vinyl) were synthesized. All of them were subjected to spectroscopic, elemental and thermogravimetric analyses. The above compounds are ionic liquids (Tm < 100 °C) and were applied to immobilization of three rhodium(I) complexes [Rh(PPh3)3Cl], [{Rh(μ-Cl)(cod)}2] and [{Rh(μ-OSiMe3)(cod)}2] as well as three platinum complexes at different oxidation states [Pt(PPh3)4], K2[PtCl4] and K2[PtCl6]. Homogeneous catalytic systems were obtained and employed in the biphasic process of hydrosilylation of octene and allyl glycidyl ether with 1,1,1,3,5,5,5-heptamethyltrisiloxane. Catalytic activities of all the systems were compared and the best one was selected. The latter made it possible to recycle 10 times the same catalyst sample without a decrease in its activity and to easy separate the catalyst from the post-reaction mixture by decantation. The developed system is one of the most effective catalytic systems for hydrosilylation k
    Applied Catalysis A General 01/2013; 451:168-175. DOI:10.1016/j.apcata.2012.10.033 · 3.67 Impact Factor
  • Polish Journal of Chemical Technology 01/2013; 15(4). DOI:10.2478/pjct-2013-0063 · 0.44 Impact Factor
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    ABSTRACT: Chiral ionic liquids (CILs) containing l-prolinate and l-lactate anions and non-chiral quaternary ammonium cations were employed in the palladium catalyzed enantioselective Heck arylation of 2,3-dihydrofuran with aryl iodides (iodobenzene, 4-iodotoluene, 2-iodoanisole, 4-iodoanisole, 4-iodoacetophenone). In all the reactions 2-aryl-2,3-dihydrofuran () was obtained as the main product with the yield up to 52% at the total conversion reaching 83%. Product , 2-phenyl-2,3-dihydrofuran, was obtained with excellent enantioselectivity (>99% ee) in a 6 h reaction with tetrabutylammonium l-prolinate. In the proposed homogeneous reaction Pd(0) nanoparticles are considered as a resting state of the catalyst and a source of soluble palladium species catalyzing the Heck reaction. The yield and stereoselectivity of the Heck reaction are strongly influenced by the kind of non-chiral cations present in CILs.
    Dalton Transactions 11/2012; 42(4). DOI:10.1039/c2dt31672b · 4.10 Impact Factor
  • Ref. No: PL212164, Year: 08/2012
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    ABSTRACT: We have synthesized alkyl(cyclohexyl)dimethylammonium bromides, formates and acetates, 2-methoxyacetates, 2-(2-methoxyethoxy)acetates, 2-[2-(2-methoxyethoxy)ethoxy]acetates, and 2-ethoxyacetates and assessed their ability to dissolve cellulose. Their physicochemical properties and microbiological activity were determined. Alkyl(cyclohexyl)dimethylammonium cation dimensions of alkyl groups are essential for cellulose solubility and are generally limited to butyl, hexyl, and octyl as effective substituents. In parallel, the alkyl group determines activity of the entire molecule against microbes. The molecule's biological activity against microbes begins when a length of the alkyl substituent begins to block cellulose solubility. We present the computational model of the solubility mechanism, composed of an ensemble of two cellobiose units and (cyclohexyl)hexyldimethylammonium acetate.
    RSC Advances 08/2012; 2(22):8429-8438. DOI:10.1039/C2RA21502K · 3.71 Impact Factor