Adsorption and correlation with their thermodynamic properties of triazine herbicides on soils

Adsorption of atrazine, prometryne and prometon was determined on six soils with different physical and chemical properties. The adsorption isotherms of three herbicides could well fit Freundlich equation. On all of six soils, adsorption of herbicides increased in the order: atrazine ≈prometon<prometryne. This order is quite the same to the calculation result of by means of excess thermodynamic properties of triazine. The Freundlich adsorption constants, K f, showed to have good correlation with organic matter(OM%) of soils for each of these herbicides, suggesting that OM is the main factor, which dominates in the adsorption process of these triazine herbicides.

Encapsulation of Co single sites in covalent triazine frameworks for photocatalytic production of syngas

The photocatalytic production of syngas using a noble-metal-free catalytic system is a promising approach for renewable energy and environmental sustainability.In this study,we demonstrate an efficient catalytic system formed by integrating Co single sites,which act as the active sites,in covalent triazine frameworks(CTFs),which act as the photoabsorber,for the photocatalytic production of syngas from CO2 in aqueous solution.The enhanced light absorption of the CTFs,which contain intramolecular heterojunctions,in conjunction with 0.8 mmol L^‒1 of the Co complex enables excellent syngas production with a yield of 3303μmol g‒1(CO:H2=1.4:1)in 10 h,which is about three times greater than that achieved using CTF without a heterojunction.In the photocatalytic reaction,the coordinated single Co centers accept the photogenerated electrons from the CTF,and serve as active sites for CO2 conversion through an adsorption-activation-reaction mechanism.Theoretical calculations further reveal that the intramolecular heterojunctions highly promote photogenerated charge separation,thus boosting photocatalytic syngas production.This work reveals the promising potential of CTFs for single-metal-site-based photocatalysis.

A new efficient route for the synthesis of 4,4′,6,6′-tetra-(azido)azo-1,3,5-triazine

A new method for the synthesis of 4,4′,6,6′-tetra(azido)azo-1,3,5-triazine (TAAT) is described. The key intermediate 4,4′,6,6′-tetra(azido)hydrazo-1,3,5-triazine (TAHT) was synthesized by nucleophilic substitution in the case of sodium azide as nucleophile. N-Bromosuccinide (NBS) was used as oxidant to oxidize TAHT by a tractable operation under mild reaction condition. The target compound TAAT was obtained with a facile process and high overall yield of 81%. The structures of TAAT and its intermediates were identified by spectroscopic methods.

2D metal‐free heterostructure of covalent triazine framework/g‐C_(3)N_(4) for enhanced photocatalytic CO_(2) reduction with high selectivity

Solar‐driven CO_(2)conversion to precious fossil fuels has been proved to become a potential way to decrease CO_(2)with producing renewable fuels,which mainly relies on photocatalysts with efficient charge separation.In this work,a metal free heterostructure of covalent triazine framework(CTF)and graphite carbon nitride(g‐C_(3)N_(4),abbreviated as CN)is applied in the CO_(2)photoreduction for the first time.Detailed characterization methods such as photoluminescence(PL)and time‐resolved PL(TR‐PL)decay are utilized to reveal the photo‐induced carries separating process on g‐C_(3)N_(4)/CTF(CN/CTF)heterostructure.The introduced CTF demonstrated a great boosting photocatalytic activity for CN,bringing about the transform rates of CO_(2)to CO reaching 151.1μmol/(g·h)with a 30 h stabilization time,while negligible CH_(4)was detected.The optimal CN/CTF heterostructure could more efficiently separate charges with a lower probability of recombination under visible light irradiation,which made the photoreduction efficiency of CO_(2)to CO be 25.5 and 2.5 times higher than that of CTF and CN,respectively.This investigation is expected to offer a new thought for fabricating high‐efficiency photocatalyst without metal in solar‐energy‐driven CO_(2)reduction.

Imidazole linker‐induced covalent triazine framework-ZIF hybrids for confined hollow carbon super‐heterostructures toward a long‐life supercapacitor

Carbon super-heterostructures with high nitrogen contents from the covalent hybrid precursors of covalent triazine frameworks(CTFs)and zeolitic imidazolic frameworks(ZIFs)are scarcely explored because of CTF's ordered structure and toxic superacid that dissolves or destabilizes the metal nodes.To solve this problem,herein,we report a straightforward two-step pathway for the covalent hybridization of disordered CTF(d–CTF)–ZIF composites via preincorporation of an imidazole(IM)linker into ordered CTFs,followed by the imidazole-site-specific covalent growth of ZIFs.Direct carbonization of these synthesized d–CTF−IM−ZIF hybrids results in unique hollow carbon super-heterostructures with ultrahigh nitrogen content(>18.6%),high specific surface area(1663m^(2)g^(−1)),and beneficial trace metal(Co/Zn NPs)contents for promoting the redox pseudocapacitance.As proof of concept,the obtained carbon super-heterostructure(Co–Zn–NC_(SNH)–800)is used as a positive electrode in an asymmetric supercapacitor,demonstrating a remarkable energy density of 61Wh kg^(−1)and extraordinary cyclic stability of 97%retention after 30,000 cycles at the cell level.Our presynthetic modifications of CTF and their covalent hybridization with ZIF crystals pave the way toward new design strategies for synthesizing functional porous carbon materials for promising energy applications.

Facile synthesis of microporous carbonaceous materials derived from a covalent triazine polymer for CO2 capture

Highly porous nitrogen-doped carbon materials were synthesized by the carbonization of a low-cost porous covalent triazine polymer, PCTP-3, which had been synthesized by the AlClcatalyzed FriedelCrafts reaction of readily available monomers. The nature of the bond and structure of the resulting materials were confirmed using various spectroscopic methods, and the effects of KOH activation on the textural properties of the porous carbon materials were also examined. The KOH-activated porous carbon（aPCTP-3c） materials possessed a high surface area of 2271 mgand large micro/total pore volumes of 0.87/0.95 cmg, respectively, with narrower micropore size distributions than the porous carbon prepared without activation（PCTP-3c）. The aPCTP-3c exhibited the best COuptakes of 284.5 and 162.3 mg gand CHuptakes of 39.6 and 25.9 mg gat 273 and 298 K/1 bar, respectively, which are comparable to the performance of some benchmark carbon materials under the same conditions. The prepared materials exhibited high CO/Nselectivity and could be regenerated easily.

Determination of triazine herbicide residues in water samples by on-line sweeping concentration in micellar electrokinetic chromatography

A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography （MEKC） was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improvement in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection （S/ N = 3：1） for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.

Clean Production for Chrome Free Leather by Using a Novel Triazine Compound

Based on a novel triazine compound,the properties of tanned leather and commercial feasibility in pilot scale have been investigated.Then this novel approach tanning was compared with conventional chrome tanning:in the condition of less-salt pickling and chrome free,the physicochemical properties including thermal stability and mechanical strength were analyzed.Meanwhile,the surface roughness and fiber dispersion were evaluated as well.The results show that the thermal stability and mechanical strength of the triazine compound tanned leather are similar to conventional chrome tanned leather,the fiber bundle is well-dispersed and much evener than that of chrome treating.The optimized tanning approach has obvious reduction in environmental impact and leads an excellent biodegradability of tanning liquor.In industrial application,the cost of materials and water treatment are reduced effectively.The production of chrome free leather can encourage the sustainable development of leather industry and protects ecological environment in some extent.

Effects of Four Kinds of Triazine Herbicides on the Photoquenching Degradation of Acetochlor

Effects of four kinds of triazine herbicides on the photodegradation of acetochlor were studied on glass surface and in aqueous solution under three kinds of light sources, i.e., xenon lamp, high pressure mercury lamp and natural sunlight. The results indicated that atrazine, simetryne, prometryne and ametryne exhibited significant effects on the photoquenching degradation of acetochlor, and there was an obvious positive correlation between their effects and the dosage of four kinds of triazine herbicides.

Styrene Epoxidation in Aqueous over Triazine-Based Microporous Polymeric Network as a Metal-Free Catalyst

Tirazine based microporous polymeric (TMP) network was found to be an efficient metal-free catalyst for the epoxidation of styrene. The reactions were performed in water as an environmentally benign medium using H2O2 as a green oxidant at ambient temperature. The reaction afforded higher yield with 90% conversion of styrene and 98% selectivity to styrene oxide in 6 h. The triazine based microporous polymeric network can be readily recovered and reused up to 4 cycles without significant loss in catalytic activity and selectivity.

Assessment of Triazine Herbicides in Soil by Microwave-assisted Extraction Followed by Gas Chromatography Coupled to Mass Spectrometry Detection

An alternative and fast method for the analysis of a mixture of nine triazines herbicides in soil is presented. The method is based on MAE （microwave-assisted extraction） of herbicides using ethyl acetate as extractant. The economy in the use of solvents coupled with the decrease in extraction time and lower power consumption make MAE a technique that meets the principles of green chemistry. MAE operational parameters, extraction time, mass of the sample and extraction temperature, were optimized by RSM （response surface methodology）. Determination of analytes was completed using gas chromatograph coupled to mass spectrometry detection. The selected triazines could be efficiently extracted by the solvent at 80 ℃ for 10 min, with 80% output of maximum power. When the optimized method was applied to analysis samples, the recoveries of analytes ranged from 81.8 to 106.0% and relative standard deviations were lower than 8.41%. The method is stable and reasonable, which can be used for the determination of ninetriazine herbicides residues in soil.

Synthesis and Photo-acid Generation of a Novel Bis(trichloromethyl)-1,3,5-triazine

A new environmentally friendly photo-acid generator（PAG）, 1-{4＇-[4,6-bis（trichloromethyl）-1,3,5-triazin- 2-yl] [ 1, 1＇-biphenyl]-4-yl}-O-acetyloxime ethanone（TZ4） consisting of both an oxime ester group and a triazine group was designed and synthesized. From the measurements of absorption, fluorescence and the photo-acid generation, it was found that the novel PAG has an excellent radical-generating efficiency. And the other three bis-（trichloromethyl） triazine derivatives 2-[2-（4-methoxyphenyl）ethenyl]-4,6-bis（trichloromethyl）-l,3,5-triazine（TZ1）, 2-[2-（3,4-dimethoxyphenyl）ethenyl]-4,6-bis（trichloromethyl）-1,3,5-triazine（TZ2） and 2-（1,3-benzodioxol-5-yl）-4,6-bis（trichloromethyl）-1,3,5-triazine（TZ3） were synthesized and studied in this work. In the acid measurement, the acid-forming performance of S-triazinyl derivatives was evaluated by the method ascertained in our laboratory. The results indicate that the novel triazine has the better acid-forming performance that subsequently catalyzes the deblocking of a protecting group in copolymers.

Cyanided Covalent Triazine Frameworks with Enhanced Adsorption Capability Toward Chloranil

Porous polymer(pyrrolopyrrole)was successfully prepared via domino-ring-formation reaction.The chemical-physical properties of cyanided covalent triazine frameworks(CTF-CN)were characteriazed by fourier transform infrared spectra(FT-IR),scanning electron microscopy(SEM),nuclear magnetic resonance(NMR),specific surface area analyzer(BET)and thermogravimetric analysis(TGA),respectively.The experimental results of adsorption of chloranil(TCBQ)in aqueous solution indicated that CTF-CN exhibited distinctive adsorption capacity toward TCBQ owing to its large specific surface area.Specifically,the adsorption equilibrium of as-prepared polymer was executed within 5 h and the calculated adsorption capacity was 499.76 mg/g.Furthermore,the adsorption kinetics could be well defined with the linear pseudo-second-order model,which implies that the chemical interaction are relative important in the course of TCBQ removal.Finally,the current studies verify that CTF-CN has unique rigid and nano-porous framework structure,which can be employed for the treatment of a series of harmful aromatic substances.

Syntheses and Crystal Structures of 1,5-Disubstituted 1,3,5-Hexahydro-triazine-2-(N-nitro)imines

The title compounds,C9H13ClN6O2S 1 and C15H17ClN6O2S 2,were synthesized and structurally characterized by elemental analysis,IR,1H NMR spectra and single-crystal X-ray diffraction.Compound 1 is in the monoclinic system,space group P21/c with a=13.7711（5）,b=10.3883（4）,c=9.7623（2）,V=1344.47（8）3,Dc=1.506 g/cm3,C9H13ClN6O2S,Mr=304.76,F（000）=632,μ=0.448 mm-1,Z=4,S=1.084,R=0.0497 and wR=0.1328 for 2640 unique reflections（Rint=0.0787） with 2089 observed ones（I2σ（I））.Compound 2 belongs to the monoclinic system,space group P21/n with a=8.3828（5）,b=14.5285（7）,c=14.2456（4）,V=1729.74（14）3,Dc=1.462 g/cm3,C15H17ClN6O2S,Mr=380.86,F（000）=792,μ=0.364 mm-1,Z=4,S=1.057,R=0.0598 and wR=0.1582 for 3384 unique reflections（Rint=0.0469） with 2833 observed ones（I2σ（I））.Compounds 1 and 2 are homologues and stabilized by intermolecular and intramolecular hydrogen bonds.Moreover,compound 2 containing C（2）–H（2）…π（thiazole） interaction is more stable than 1.

Evaluation of Commercial Active Carbons for the Removal of s-Triazine Herbicides from Waters

The adsorption capacity of powdered active carbons, used in a water treatment facility, for the removal of the triazine herbicides propazine, prometryn and prometon, was evaluated. Kinetic studies showed that some of the carbon samples used could be suitable in the practice for the treatment of moderate contents of the herbicides in contaminated waters. Equilibrium studies showed that the data fit the Frumkin isotherm. The results show that in the adsorption process there are repulsive lateral interactions that depend mainly of the adsorbate molecules rather than the nature or distribution of adsorption sites. Such lateral interactions seem to be established mainly between the isopropyl groups of adjacent molecules, being of the same order for the three molecules. The effectiveness of the active carbons was evaluated by determining the percentage of reduction achieved by each product.

Gas-phase Thermolysis of 1,2,3-triazole and 1,2,3-triazine Derivatives

Gas-phase thermolysis of 1-ethoxycarbonyl-benzotriazole under static, FVP and microwaves condition yielded N^1 and NZ-ethylbenzotriazole, 2-ethoxy-1,3-benzooxazole, biphenylene and oxazolidin-2-one. On the other hand, direct condensation and pyrolysis of naphtho[1,8-de][1,2,3]triazine with ethylisocyanate, phenylisocyanate and their isothiocayanates, benzoylisothiocyanate and thiourea at 150-160 ℃ or under microwaves irradiation produced the corresponding naphthopyrimidin-2-one derivatives.

CHEMISTRY OF 1,2,4—TRIAZINES XIX THE ANOMALOUS SUBSTITUTED BENZENE SULFONATION AND PROPERTIES OF NUCLEOPHILIC ATTACK ON 6-CARBON OF 3-METHYLTHIO-5-HYDROXY-1,2,4-TRIAZINE

3-Methylthio-5-hydroxy-1,2,4-triazine(1c)reacted with substituted benzenesulfonyl chloride to give 3-methylthio-5-oxy-1,2,4-triazin-6-yl pyridinium betaine(4)in anhydrous pyridine.But when NaOH/H_2O/CH_3COCH_3 or NaOH/CH_3OH were used as reactant and solvent,3-methylthio-4-substituted benzenesulfonyl-5-oxo-6-hydroxy-1,4,5,6-tetrahydro-1,2,4-triazine(6)or 1-tosyl-3-methylthio-5-oxo-6-methyloxy-1,4,5,6-tetrahydro-1,2,4-triazine(7)was obtained respectively.The above reactions show anomalous properties of nucleophilic attack on 6-carbon in 1,2,4-triazine ring.

Direct Synthesis of Ultrathin Crystalline Two-Dimensional Triazine Polymers from Aldoximes

The efficient synthesis of ultrathin crystalline twodimensional(2D)polymers with well-defined repeating units is essential to realize their broad applications but remains a great challenge.Herein,we report a new strategy to directly synthesize a series of few-layer 2D triazine-based polymers(2DTPs)via trimerization reaction of aromatic aldoximes in one step with a high yield of 85%using AlCl3 as catalyst under solvent-free conditions.The obtained 2D-TPs show high crystallinity,a lateral size of several micrometers,an ultrathin thickness less than 2 nm,and good dispersibility and processability.Through semi-in situ and detailed control experiments,we reveal that the 2D polymerization reaction is a two-step process of dehydration and then cyclotrimerization,and AlCl3 acts as not only catalyst but also an in situ generated template for promoting the formation of 2D-TPs.When explored as a new polymeric anode for potassium-ion batteries,the 2D-TP displayed an extraordinary reversible specific capacity of 356 mAh g^(−1)at 0.05 A g^(−1),which is among the best performances ever reported,outstanding rate capability(153 mAh g^(−1)at 1 A g^(−1)),and excellent cycling stability with 95.1%capacity retention after 1000 cycles at 1 A g^(−1).

Covalent Triazine Framework Nanosheets:Synthesis and Energy Conversion and Storage

Covalent triazine framework nanosheets (CTF NSs),an emerging class of two-dimensional nanomaterials,have received great attention due to their abundant active sites,permanent porosity,molecular structural diversity,superior chemical/thermal stability,and short charge diffusion path,enabling technological breakthroughs in a myriad of applications. The forefront developments and applications of CTF NSs as photocatalysts and electrochemical electrodes have conferred superior performance and made great impact in the field of energy and advanced catalysis. This forward-looking review aims to summarize the research trends,synthesis,properties of CTF NSs and their CTF counterpart,and highlight their progress in applications with respect to energy storage and conversion devices. Finally,the current challenges and future perspectives for CTF NSs are also presented.

Advances in poly(heptazine imide)/poly(triazine imide) photocatalyst

Polymeric carbon nitride(PCN)has garnered increasing attention as a metal-free photocatalyst with a suitable band gap.In efforts to enhance its photocatalytic performance,researchers have examined various PCN materials,including poly(heptazine imide)(PHI)and poly(triazine imide)(PTI),two isomers within the PCN family that exhibit distinct and superior photocatalytic activity compared to other forms.The challenge,however,lies in the common practice among researchers to categorize PHI and PTI along with other PCN types under the overarching term“g-C_(3)N_(4),”which significantly impedes optimization efforts.The objective of this review is to provide comprehensive insights into the structural features,photoelectrochemical properties,and effective characterization methods employed for distinguishing between PHI and PTI materials.The review also summarizes various optimization strategies,such as crystallinity adjustments,defect engineering,morphology control,constructing heterojunction,and atomic-level metal loading dispersion,to elevate the photocatalytic activity of PHI and PTI,in addition to summarizing the history of carbon nitride development.Furthermore,this review highlights the primary applications of PHI and PTI,encompassing nitrogen fixation,biomass conversion,organic synthesis,CO_(2)reduction,pollutant degradation,H_(2)O_(2)production,and photocatalytic water splitting.Lastly,the prospects and challenges associated with further advancing PHI and PTI are thoroughly examined.