Dimethylbenzylamine Research Articles

Bacterial dealkylation of benzalkonium chlorides in wastewater produces benzyldimethylamine, a potent N-nitrosodimethylamine precursor

N-nitrosodimethylamine (NDMA) is a carcinogenic disinfection byproduct that forms during chloramine disinfection of municipal wastewater effluents which are increasingly used to augment drinking water supplies due to growing water scarcity. Knowledge of wastewater NDMA precursors is limited and the known pool of NDMA precursors has not closed the mass balance between precursor loading, precursor NDMA yield, and formed NDMA. Benzalkonium chlorides (BACs) are the most prevalent quaternary ammonium surfactants and have antimicrobial properties. The extensive utilization of BACs in household, commercial and industrial products has resulted in their detection in wastewater at elevated concentrations. We report the formation of a potent NDMA precursor, benzyldimethylamine (BDMA) from the biodegradation of BACs during activated sludge treatment. BDMA formation and NDMA formation potential (FP) were functions of BAC and mixed liquor suspended solids concentration at circumneutral pH, and the microbial community source. Sustained exposure to microorganisms reduced NDMA FP through successive dealkylation of BDMA to less potent precursors. BAC alkyl chain length (C8 – C16) had little impact on NDMA FP and BDMA formation because chain cleavage occurred at the C–N bond. Wastewater effluents collected from three facilities contained BDMA from 15 to 106 ng/L, accounting for an estimated 4 to 38 % of the NDMA precursor pool.

Potential hazards of typical small molecular organic matters in shale gas wastewater for wheat irrigation: 2-butoxyethanol and dimethylbenzylamine

2-butoxyethanol (BE) and dimethylbenzylamine (DMBA) are small molecular organic compounds commonly found in shale gas wastewater (SGW) and environmental samples, yet their environmental risks in exposure and irrigation reuse have not been thoroughly studied. From the perspectives of physicochemical properties and toxicity, seven groups of irrigation treatment were designed for wheat irrigation according to the concentration gradient. Overall, wheat growth was normal, but higher DMBA concentrations resulted in more severe growth inhibition. The absorption of BE by various tissues of wheat was positively correlated with its concentration, while the absorption of DMBA by wheat stems showed the same trend. Interestingly, there was no significant difference in the absorption of DMBA by wheat grains in different groups. The detection results of nutritional and heavy metal elements in wheat tissues showed that the presence of organic compounds changed the relative sensitivity of wheat leaves and grains to some elements (such as Mg, Mn, Mo, etc.) enrichment. The Cd and Pb contents of wheat grains in all groups complied with national safety standards, but the As or Cr concentration in wheat grains treated with BE or DMBA exceeded the limits in some cases. Transcriptome sequencing, GO annotation, and KEGG enrichment analysis revealed similar gene functions and metabolic pathways enriched by BE and DMBA. The safe and sustainable agricultural reuse of SGW still has great potential as a promising water resources management strategy.

Studies of the rate of gold sorption by the AM-2B anionite from cyanide-alkaline solutions

The paper presents the results of studies on the sorption leaching of gold-containing ore of the Vasilkovskoye deposit. Kinetic dependences of the sorption of gold and associated metals from cyanide-alkali solutions under different physical and chemical factors were obtained. It was found that gold on the AM-2B resin sorbed at a higher rate than, for example, copper and zinc. The solutions were analyzed using modern devices of a new generation: FT-IR spectrometer "Avatar 370". Laboratory studies were performed to determine the gold sorption rate by the AM-2B anionite from cyanide-alkaline solutions. It was found in the process of sorption of gold from multicomponent cyanide-alkali solutions on AM-2B anionite of mixed basicity, with the macroporous structure containing benzyl dimethylamine and dibenzyl dimethyl ammonium functional groups, that an important factor of qualitative and quantitative separation of gold and impurity metals is the concentration of cyanide and hydroxyl ions in solution. The temperature effect on the sorption rate of gold from cyanide-alkali solutions was studied with the temperature dependences F of t, Bt, of t, ln (l - F) of t, and D of t that show that the sorption process of dicyanoaurate ions is controlled by mixed diffusion.

Tertiary amine as an efficient CO2 switchable solvent for extracting lipids from hypersaline microalgae

Considering the momentous cost drivers in energy efficient algal biorefinery processes, a green alternative in extracting lipid from microalgae is anticipated. Switchable solvent system using tertiary amines namely DMBA (Dimethylbenzylamine), DMCHA (Dimethylcyclohexylamine), and DIPEA (Diisopropylethylamine) for lipid extraction from wet hypersaline microalgae was investigated in this study. Interestingly, present study showed that at 1:1 (v/v of fresh DMBA solvent: microalgal biomass), and for 1 h extraction time, the lipid yield was 41.9, 26.6, and 33.3% for Chlorella sp. NITT 05, Chlorella sp. NITT 02, and Picochlorum sp. NITT 04, respectively and for recovered DMBA solvent, at 1:1 (v/v) and for 1 h extraction time, the lipid yield was 40.8, 25.97, and 32%, respectively. Similarly, lipid extraction using DMCHA solvent for Chlorella sp. NITT 05, Chlorella sp. NITT 02, and Picochlorum sp. NITT 04 at 1:1 (v/v of solvent: microalgal biomass) and 1 h extraction time showed 34.28, 24.24 and 23.33% lipids, respectively for fresh solvent and 34.01, 24.24 and 23.18% for recovered solvent respectively; while DIPEA was not competent in lipid extraction from three tested microalgae. FAME profile revealed the presence of saturated fatty acids as 43.04%, 40.98%, 38.45% and monounsaturated fatty acids as 28.38%, 27.05%, 23.3% for Chlorella sp. NITT05, Picochlorum sp. NITT04, Chlorella sp. NITT02, respectively. This study attributes Chlorella sp. NITT05 and Picochlorum sp. NITT04 to be ideal algal species for biodiesel production.

Liquid-liquid extraction of phosphorus from sulfuric acid solution using benzyl dimethyl amine

This study addresses the liquid-liquid extraction behavior of phosphorus from a sulfuric acid solution using benzyl dimethyl amine (BDMA) in kerosene. The extraction equilibria investigated with varied BDMA concentrations could reveal the formation of $$\overline {3[{\rm MA }] \cdot [{{\rm{H}}_3}{\rm{P}}{{\rm{O}}_4}]} $$ complex in the organic phase. The thermodynamic properties determined at various temperatures indicated that the process was exothermic with a calculated enthalpy (ΔH⊖) of −24.0 kJ·mol−1. The organic-to-aqueous phase (O/A) volume ratio was varied to elucidate the quantitative extraction of phosphorus. The McCabe-Thiele diagram plotted for the extraction isotherm was validated for the requirement of three counter-current stages in the extraction at an O/A volume ratio of 2.0/3.5. The back-extraction of phosphorus from the loaded organic phase was quantitatively achieved by contacting 4.0 mol·L−1 H2SO4 solution in three stages of counter-current contact at an O/A volume ratio of 3/2. This study can be applied to remove phosphorus from the sulfuric acid leach solutions of monazite processing, and many other solutions.

Organic compounds in Weiyuan shale gas produced water: Identification, detection and rejection by ultrafiltration-reverse osmosis processes

Quantification of organic pollutants in flowback and produced water is essential to design appropriate treatment strategy and predict the potential environmental toxicity associated with unconventional energy production. Herein, we firstly characterized the important range chemicals of produced water (PW) collected from Weiyuan shale gas play, China. Ultra-high resolution (>10 M) electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry was used to gain insights into molecular compositions of mass range 170–1,000 Da. Oxygen-containing organic compounds (CHO) was the dominant type of compounds in the PW, and classes of O8 and O9 had the highest relative abundance. Highly unsaturated phenolic and aliphatic compounds were identified as the main compounds. Three low molecular weight (LMW, <170 Da) compounds, dimethylbenzylamine (DMBA), indoline, and 6-methyl-quinoline, were firstly revealed in the PW, with their concentrations of 137.11 μg/L, 5.48 μg/L, and 0.9 μg/L, respectively, as determined by liquid chromatography coupled to tandem mass spectrometry. An integrated process of ultrafiltration coupled with reverse osmosis was employed to treat the PW and achieved 78.3%, 96.3%, and 100% removal for these three chemicals. The concentration of DMBA in the effluent is 29.75 μg/L, which potentially cause environmental risks even after advanced membrane treatment, suggesting that LMW chemicals such as DMBA in PW deserves special attention.

Cleaner production of rare earth elements from phosphorus-bearing sulfuric acid solution of vein deposit monazite

In the present study, the recovery of rare earth elements (REEs; viz. cerium, lanthanum, and yttrium) from sulfate leach liquor of vein deposit Korean monazite has been investigated using the solvo-chemical techniques. The dissolved phosphorus (373 mg L−1), which may significantly affect the products’ purity, was selectively removed using the benzyl-di-methyl amine (BDMA). The logarithmic distribution vs. BDMA concentration along with spectral analysis of the organic phases revealed the formation of extracted species 3[BDMA].[H3PO4]¯. The quantitative removal of phosphorus was achieved in three stages of counter-current extraction (CCE) under the organic-to-aqueous (O:A) ratio of 1.0:1.5, leaving REEs’ into the raffinate. Subsequently, Cyanex 923 was employed to selectively extract cerium(IV) from P-depleted solution under the varying parameters of extractant and sulfuric acid concentration, temperature, and O:A ratio. The quantitative extraction of cerium (∼99% from 864 mg L−1 feed concentration) showing exothermic nature was achieved at an O:A of 1:2 under three stages of CCE while using 0.15 mg L−1 extractant into organic phase and 1.12 mol L−1 H2SO4 into aqueous phase. Further, the experimental results and spectral analysis of the organic phases could reveal that cerium solvates as [Ce(SO4)2].2[Cyanex 923].[HSO4−]¯ species. Cerium was successfully stripped from loaded organic by contacting with a higher concentration of H2SO4 solution (≥4.0 mol L−1) in presence of 0.1 mol L−1 H2O2, yielding an enriched high-purity solution of 2.54 g L−1 cerium. Lanthanum and yttrium were recovered from the Ce-depleted raffinate by co-precipitation with oxalic acid, forming a mixture of C6La2O12.10H2O and C6Y2O12.4H2O. The study approaches a cleaner production of high-purity REEs for clean energy programs under Sustainable Development Goals.

Synthesis of a highly fluorescent N,N‐dimethyl benzylamine–palladium(II) curcuminate complex and its application for determination of trace amounts of water in organic solvents

In this work a new highly fluorescent N,N-dimethyl benzylamine-palladium(II) yu complex was synthesized by the reaction of [Pd2 {(C,N-C6 H4 CH2 N(CH3 )2 }2 (μ-OAc)]2 ] with curcumin. The structure of the synthesized complex was characterized using Fourier transform infra-red (FT-IR) spectroscopy, 1 H nuclear magnetic resonance spectroscopy, and elemental analysis. Fluorescence quantum yield (ΦF ) values of the synthesized complex in dimethyl sulfoxide (DMSO), acetonitrile, ethanol, and methanol were 0.160, 0.104, 0.068, and 0.061, respectively. The fluorescence signal of the complex in the organic solvents was very sensitive to the water content of the organic solvent. The quenching effect of water was used to determine trace amounts of water in the heteroatom-containing organic solvents (ethanol, methanol, acetonitrile) and redox-active solvents (DMSO). The linear ranges for determination of water (v/v %) in ethanol, DMSO and acetonitrile were found to be 0.03-14.5, 0.08-13.8, and 0.07-18.8, respectively. Two linear ranges were found for determination of water (v/v %) in methanol (0.1-1.2 and 4.7-25.0). Detection limit (DL) values were calculated to be 0.001, 0.05, 0.004, and 0.01 (v/v %) in ethanol, methanol, acetonitrile, and DMSO, respectively. The proposed method overcomes the problems of the standard Karl Fischer method for determination of water in DMSO. In addition, it gave the best DL value for determination of water in ethanol compared with all published papers to date.

On the Features of Sorption Concentration of Ru on Super-Crosslinked Polystyrenes during the Analysis of Rocks by the Method of Inductively Coupled Plasma Mass Spectrometry

New sorption systems based on a series of super-crosslinked polystyrenes of brands HP and Styrosorb for the concentration of Ru from the solutions obtained after decomposition of rocks are studied. To extract Ru according to a reversed-phase mechanism, aromatic amines (methylbenzylamine (MBA), dimethylbenzylamine (DMBA), dibenzylmethylamine (DBMA)), as well as aliphatic tributylamine (TBA), are used for the first time. It is shown that reverse 60% extraction of Ru from the standardized test solution can be reached in the Styrosorb-514–TBA–1M HCl sorption system in ethanol as a desorption agent. An important role of sample preparation of a solid sample is revealed by the analysis of the reference standards (RSs) of ultrabasic and basic rocks. It is found that, for the quantitative (100%) extraction of Ru in the selected sorption system, the only suitable way of transferring a solid sample to a solution is smelting to NiS matte followed by dissolving of the matte in aqua regia and transferring it to concentrated HCl. The influence of Ni during the mass spectrometric determination of Ru by 99Ru in a broad range of concentrations (20–2000 μg/L) is studied; it is shown that the presence of Ni does not make the Ru concentration too high. The conducted experiments have displayed the possibility for using the sorption system based on Styrosorb-514 when estimating the low content of Ru in rock samples, which is confirmed by the analysis of the reference standards of ultrabasic and basic rocks GPt-5, GPt-6, and SARM-7. The obtained data on Ru content in these objects coincide with the certified values within the confidence interval.

A Rieske-Type Oxygenase of Pseudomonas sp. BIOMIG1 Converts Benzalkonium Chlorides to Benzyldimethyl Amine.

Recently, an array of eight genes involved in the biotransformation of benzalkonium chlorides (BACs)-an active ingredient of many disinfectants-to benzyldimethyl amine (BDMA) was identified in the genome of Pseudomonas sp. BIOMIG1, which is a bacterium present in various environments and mineralizes BACs. In this study, we showed that heterologous expression of an oxygenase gene (oxyBAC) present in this gene array in E. coli resulted in formation of BDMA from BACs at a rate of 14 μM h-1. oxyBAC is phylogenetically classified as a Rieske-type oxygenase (RO) and belongs to a group which catalyzes the cleavage of C-N+ bond between either methyl or alkyl ester and a quaternary nitrogen (N) of natural quaternary ammonium compounds such as stachydrine, carnitine, and trimethylglycine. Insertion of two glycines into the Rieske domain and substitution of tyrosine with leucine in the mononuclear iron center differentiate oxyBAC from other ROs that cleave C-N+, and presumably facilitate the cleavage of saturated alkyl chain from quaternary N via N-dealkylation reaction. In addition, unlike other ROs, oxyBAC did not require a specific reductase to function. Our results demonstrate that oxyBAC represents a new member of RO associated with BAC degradation, and have applications for controlling the fate of BACs in the environment.

Mechanism and toxicity research of benzalkonium chloride oxidation in aqueous solution by H2O2/Fe(2+) process.

As widely used disinfectants, the pollution caused by benzalkonium chloride (BAC) has attracted a lot of attention in recent years. Since it is not suitable for biodegradation, BAC was degraded firstly by Fenton advanced oxidation technologies (AOTs) in this research to enhance the biodegradability of the pollutions. The result revealed that the optimal molar ratio of H2O2/Fe(2+) for BAC degradation was 10:1, and the COD removal rate was 32%. To clarify the pathway of degradation, the technique of GC-MS was implemented herein to identify intermediates and the toxicity of those BAC intermediates were also novelty tested through microbial fuel cells (MFC). The findings indicated that ten transformation products including benzyl dimethyl amine and dodecane were formed during the H2O2/Fe(2+) processes, which means the degradation pathway of BAC was initiated both on the hydrophobic (alkyl chain) and hydrophilic (benzyl and ammonium moiety) region of the surfactant. The toxicity of BAC before and after treated by Fenton process was monitored through MFC system. The electricity generation was improved 337% after BAC was treated by H2O2/Fe(2+) oxidation processes which indicated that the toxicity of those intermediates were much lower than BAC. The mechanism and toxicity research in this paper could provide the in-depth understanding to the pathway of BAC degradation and proved the possibility of AOTs for the pretreatment of a biodegradation process.

Uranium(iii) and thorium(iv) alkyl complexes as potential starting materials.

The synthesis and characterisation of a rare U(iii) alkyl complex, U[η4-Me2NC(H)C6H5]3, using the dimethylbenzylamine (DMBA) ligand has been accomplished. While attempting to prepare the U(iv) compound, reduction to the U(iii) complex occurred. In the analogous Th(iv) system, C-H bond activation of a methyl group of one dimethylamine was observed yielding Th[η4-Me2NC(H)C6H5]2[η5-(CH2)MeNC(H)C6H5] with a dianionic DMBA ligand. The utility of these complexes as starting materials has been analyzed using a bulky dithiocarboxylate ligand to yield tetravalent actinide species.

PROBING THE POSTGELATION REACTIONS OF EPOXIDIZED NATURAL RUBBER CROSS-LINKED WITH DODECENYL SUCCINIC ANHYDRIDE

ABSTRACT Pregelled mixes of an epoxidized natural rubber, known as ENR50, containing dodecenyl succinic anhydride (DDSA) as cross-linking agent and dimethyl benzyl amine (DMBA) as catalyst, were cured isothermally at 160 °C, and the progress of the reactions was followed by both thermal analysis (differential scanning calorimetry and thermogravimetric analysis [TGA]) and infrared spectroscopy (Fourier transform near-infrared and attenuated total reflection). The curing reactions were found to be approximately first order for both heat of reaction associated with cross-linking and the disappearance of the epoxy groups, even though the reduction of epoxy group concentration was found to be substantially greater than the amount expected from reactions with the anhydride, because of the formation of large quantities of vicinal OH groups. The TGA data have indicated that the pregelled mixes undergo more extensive anaerobic degradation at higher temperatures than the un–cross-linked elastomer, which is accelerated by the presence of the DMBA catalyst.

Kinetics of the epoxy–thiol click reaction initiated by a tertiary amine: Calorimetric study using monofunctional components

An analysis of the kinetics of the epoxy–thiol reaction in a model stoichiometric system of monofunctional reagents, 3-mercaptopropionate (BMP) and phenylglycidylether (PGE) is reported. Benzyldimethylamine (BDMA) was employed as initiator in amounts ranging from 0.5 to 2wt%. These formulations showed a kinetic behavior qualitatively similar to that of commercial adhesives and coatings formulated for a room-temperature cure. Isothermal DSC scans revealed the existence of a relatively long induction period preceding a fast autocatalytic reaction step. Dynamic DSC scans showed that the reaction was shifted to a lower temperature range by increasing the storage period of the initial formulation at 20°C. This unusual kinetic behavior could be modeled assuming that thiolate anions, slowly generated during the induction period, initiated a fast autocatalytic propagation/proton transfer reaction. The kinetic model included a pseudo-steady state for the initiator concentration and an equilibrium reaction between epoxy and OH groups generated by reaction. A reasonable fitting of isothermal and dynamic DSC runs was achieved in a broad range of temperatures and amine concentrations. In particular, both the length of the induction time and the effect of the storage period were correctly predicted.

Confocal Raman Microscopy for pH-Gradient Preconcentration and Quantitative Analyte Detection in Optically Trapped Phospholipid Vesicles

The ability of a vesicle membrane to preserve a pH gradient, while allowing for diffusion of neutral molecules across the phospholipid bilayer, can provide the isolation and preconcentration of ionizable compounds within the vesicle interior. In this work, confocal Raman microscopy is used to observe (in situ) the pH-gradient preconcentration of compounds into individual optically trapped vesicles that provide sub-femtoliter collectors for small-volume samples. The concentration of analyte accumulated in the vesicle interior is determined relative to a perchlorate-ion internal standard, preloaded into the vesicle along with a high-concentration buffer. As a guide to the experiments, a model for the transfer of analyte into the vesicle based on acid-base equilibria is developed to predict the concentration enrichment as a function of source-phase pH and analyte concentration. To test the concept, the accumulation of benzyldimethylamine (BDMA) was measured within individual 1 μm phospholipid vesicles having a stable initial pH that is 7 units lower than the source phase. For low analyte concentrations in the source phase (100 nM), a concentration enrichment into the vesicle interior of (5.2 ± 0.4) × 10(5) was observed, in agreement with the model predictions. Detection of BDMA from a 25 nM source-phase sample was demonstrated, a noteworthy result for an unenhanced Raman scattering measurement. The developed model accurately predicts the falloff of enrichment (and measurement sensitivity) at higher analyte concentrations, where the transfer of greater amounts of BDMA into the vesicle titrates the internal buffer and decreases the pH gradient. The predictable calibration response over 4 orders of magnitude in source-phase concentration makes it suitable for quantitative analysis of ionizable compounds from small-volume samples. The kinetics of analyte accumulation are relatively fast (∼15 min) and are consistent with the rate of transfer of a polar aromatic molecule across a gel-phase phospholipid membrane.

New catalysts for diglycidyl ether of bisphenol A curing based on thiol–epoxy click reaction

The thiol–epoxy click reaction has been employed in the curing of diglycidyl ether of bisphenol A (DGEBA) using latent amine precursors in ratios of 0.5 and 2phr. The kinetics of the curing of mixtures of DGEBA/thiol/amine precursor was studied by calorimetry under isothermal and non-isothermal conditions. The latent characteristics of the formulations containing amine precursors were investigated by rheometry and calorimetry. The thermal stability of the thermosets and their thermomechanical characteristics were evaluated by thermogravimetry and dynamomechanical analysis. The new formulations were compared with those containing benzyl dimethyl amine or 1-methylimidazole as catalysts. The use of amine precursors in these systems extended the pot-life of the formulations and permitted a better control of the curing process.

The influence of tertiary amine accelerators on the curing behaviors of epoxy/anhydride systems

Accelerators have significant effects on the curing behaviors of epoxy/anhydride (diglycidyl ether of bisphenol-F/methylhexahydrophthalic anhydride, DGEBF/MeHHPA) systems. Non-isothermal DSC was used to investigate the influence of dimethyl benzylamine (BDMA, 0.2phr/0.5phr) and Tris-(dimethyl aminomethyl) phenol (DMP-30, 0.2phr/0.5phr) on the curing behaviors of DGEBF/MeHHPA systems, respectively. When the amount of accelerators was kept constant, the activation energy calculated by Kissinger method changed slightly in the presence of either BDMA or DMP-30. And, with increasing the accelerator content from 0.2phr to 0.5phr, the value of activation energy decreased from 115kJ/mol to 85kJ/mol. Furthermore, the calculation results of Málek method identified that all systems in this study fitted Sesták–Berggren (SB) model and the corresponding model parameters, m and n, were obtained. It was found that the contribution of autocatalytic reaction with low accelerator content (0.2phr) was far less than that with high accelerator content (0.5phr).

Curing behavior of dicyandiamide/epoxy resin system using different accelerators

Various amounts of dicyandiamide (Dicy), two grades of epoxy resins, i.e. Epiran 06 and Epikote 828, and three different accelerators including benzyl dimethyl amine (BDMA), 3-(4-chlorophenyl)-1,1-dimethyl urea (Monuron) and 2-methyl imidazole (Im) were used in curing of Dicy/epoxy resin system. Both of the used epoxy resins were based on diglycidyl ether of bisphenol A (DGEBA). The effects of type and concentration of accelerators on curing behavior were studied by differential scanning calorimetry (DSC) method in dynamic or non-isothermal mode. The optimum concentration of Dicy for curing of epoxy resins was obtained based on the glass transition temperature of the cured epoxy/Dicy formulations. The maximum glass transition temperature of 139 °C was obtained at the stoichiometric ratio of Dicy to epoxy of 0.65. The results showed that BDMA has a broader curing peak in DSC and starts the cure reaction earlier than the others. However, Monuron has a narrow curing reaction peak with good cure latency. The tensile properties of Dicy-cured Epiran 06 and Epikote 828 epoxy resins reinforced with chopped strand mat showed that these two epoxy resins have similar mechanical properties. For composites based on the Epiran 06 and Epikote 828 reinforced with 40 wt % glass chopped strand mat, tensile strength and modulus were 156 and 153.4 MPa and 11.6 and 12.4 GPa, respectively.

Aerobic Biotransformation of n-Tetradecylbenzyldimethylammonium Chloride by an Enriched Pseudomonas spp. Community

The biotransformation of n-tetradecylbenzyldimethylammonium chloride (C(14)BDMA-Cl), a quaternary ammonium compound (QAC), under aerobic conditions by an enriched microbial community growing on benzalkonium chlorides (BACs) was investigated. Biotransformation of C(14)BDMA-Cl commenced with cleavage of the C(alkyl)-N bond and formation of benzyldimethylamine (BDMA). BDMA was further degraded, but in contrast to a previously reported BAC biotransformation pathway, neither benzylmethylamine (BMA) nor benzylamine (BA) was detected as a BDMA biotransformation product. Kinetic assays further confirmed that BMA and BA were not intermediates of C(14)BDMA-Cl transformation by the enriched community. Thus, BDMA is thought to be transformed to dimethylamine and benzoic acid via debenzylation. The biomass-normalized rate of C(14)BDMA-Cl biotransformation was 0.09 μmol/[mg of volatile suspended solids (VSS)·h]. The Microtox acute toxicity EC(50) value of BDMA was 500 times higher than that of C(14)BDMA-Cl. Thus, the aerobic biotransformation of C(14)BDMA-Cl to BDMA results in substantial toxicity reduction. Phylogenetic analysis of Bacteria diversity indicated that the majority of the sequenced clones (98% of the clone library) belonged to the genus Pseudomonas.

Preparation of high‐substituted cationic starch in presence of organic bases

AbstractCross‐linked N‐(hydroxypropyl)–N,N,N–trimethylammonium starch chlorides (CQS) with preserved microgranules, degree of substitution (DS) from 0.18 to 1.05 are prepared by reaction of starch with glycidyltrimethylammonium chloride (GTAC) accelerated by benzyltrimethylammonium hydroxide (BTMAOH) or tertiary amines–triethylamine (TEA) and dimethylbenzylamine (DMBA). When BTMAOH instead of NaOH is used as a catalyst, the reaction of cross‐linked starch (CS) with GTAC proceeds slightly slower and with a lower efficiency (RE). DMBA unexpectedly showed similar catalyst efficiency as BTMAOH. It is suggested that the reason for such phenomena is the reaction of GTAC with tertiary amines and the formation of strong bases – quaternary ammonium hydroxides. They actually catalyse starch cationization. DMBA is more active in this reaction in comparison with TEA. It is shown that, due to a higher amount of quaternary ammonium hydroxides in the liquid phase of the reaction mixture, the yield of starch cationization decreases. Cationization in the presence of organic bases provides higher sorption capabilities to the modified polysaccharide.