Kinds Of Amines Research Articles

Development of Iron‐Based Single Atom Materials for General and Efficient Synthesis of Amines

AbstractEarth abundant metal‐based heterogeneous catalysts with highly active and at the same time stable isolated metal sites constitute a key factor for the advancement of sustainable and cost‐effective chemical synthesis. In particular, the development of more practical, and durable iron‐based materials is of central interest for organic synthesis, especially for the preparation of chemical products related to life science applications. Here, we report the preparation of Fe‐single atom catalysts (Fe‐SACs) entrapped in N‐doped mesoporous carbon support with unprecedented potential in the preparation of different kinds of amines, which represent privileged class of organic compounds and find increasing application in daily life. The optimal Fe‐SACs allow for the reductive amination of a broad range of aldehydes and ketones with ammonia and amines to produce diverse primary, secondary, and tertiary amines including N‐methylated products as well as drugs, agrochemicals, and other biomolecules (amino acid esters and amides) utilizing green hydrogen.

Development of Iron-Based Single Atom Materials for General and Efficient Synthesis of Amines.

Earth abundant metal-based heterogeneous catalysts with highly active and at the same time stable isolated metal sites constitute a key factor for the advancement of sustainable and cost-effective chemical synthesis. In particular, the development of more practical, and durable iron-based materials is of central interest for organic synthesis, especially for the preparation of chemical products related to life science applications. Here, we report the preparation of Fe-single atom catalysts (Fe-SACs) entrapped in N-doped mesoporous carbon support with unprecedented potential in the preparation of different kinds of amines, which represent privileged class of organic compounds and find increasing application in daily life. The optimal Fe-SACs allow for the reductive amination of a broad range of aldehydes and ketones with ammonia and amines to produce diverse primary, secondary, and tertiary amines including N-methylated products as well as drugs, agrochemicals, and other biomolecules (amino acid esters and amides) utilizing green hydrogen.

Preparation of Naphthalenediimide-Decorated Electron-Deficient Photochromic Lanthanide (III)-MOF and Paper Strip as Multifunctional Recognition and Ratiometric Luminescent Turn-On Sensors for Amines and Pesticides.

Detecting toxic amine and pesticide contamination in the environment is one of the most pressing issues for environmental sustainability. In this work, two 3D Ln-BINDI complexes [Ln = Eu (1), Sm (2); H4BINDI (N, N'-bis(5-isophthalic acid)-1,4,5,8-naphthalenediimide)] have been designed and synthesized. Crystal structure of [Eu2(BINDI) (NO3)2(DMA)4]·2DMA (complex 1) featuring the lvt topology was determined by X-ray single-crystal diffraction. A multi-functional ratiometric luminescence sensor benefitting from π-electron-deficient NDI moieties and f-f transition characteristics of lanthanide Eu3+ ions for complex 1 has been investigated. Markedly, complex 1 exhibit completely different selective fluorescence ratiometric turn-on responses and pretty high sensitivity behaviors to aromatic amines (OPD), aliphatic amines (n-BA), and pesticides (TBZ), respectively, which are driven by interactions between the electron-donating amino group and acceptor NDI site, contributing to complex 1 as a potential ratiometric luminescent turn-on sensor for practical environmental applications. A PVA/1@paper strip can be used as a potential size selectivity sensor for the practical detection of aliphatic amine vapors in the environment through visual chromic fluorescence enhancement. Because NDIs can undergo one-electron reduction to form stable NDI· free radicals, solid complex 1 can visually distinguish different kinds of amines by selective amine-specific color changes and has the photochromic property of erasable inkless printing.

A graphical approach for mixed ratio optimisation in the binary mixed amine solution

Chemical absorption method plays an important role in the process of CO2 separation. One major problem for chemical absorption is huge energy consumption, which is affected by the performance of absorbents. Developing a type of absorbent with high absorption capacity and low regenerative energy consumption is a research topic that attracts attention. The combination of two or more amines is one way to develop new solvents. However, the change of amine liquid ratio can cause a series of complex nonlinear changes in absorption capacity, absorption heat, the heat of vaporisation and sensible heat. It is of interest to visualise the amine solution mixing ratio optimisation to help reduce the energy consumption and increase the absorption capacity. Derivative analysis of standardised vs variables diagram (DSVD), a kind of graphical method based on maximum benefit and minimum consumption, is proposed to determine the optimal mixing ratio of binary amine solution. This novel approach helps to visualise what kind of amines are not suitable for compounding, what kind of amines have the best compounding ratio, and how to determine the optimal compounding ratio. The optimal mixing ratio of the Methyldiethanolamine (MDEA) - Piperazine (PZ) system and MDEA - Monoethanolamine (MEA) were optimised by this method. The optimal ratio of MDEA - PZ and MDEA - MEA are 0.6 (PZ: MDEA = 0.6:0.4, wt.%) and 0.8 (MEA: MDEA = 0.8:0.2, wt.%).

Investigation of Alkanol-Amine Solvents and their Blends for CO2 Removal from Natural Gas using Aspen-Hysys

The removal of carbon dioxide (CO2) from natural gas is vital towards meeting pipeline sales gas specifications and evading operational complications during the liquefaction of natural gas. Therefore, the removal of CO2 from natural gas is necessary for the efficient utilization of natural gas and for the reduction of global CO2 emission. It is also vital for the effective liquefaction process in the liquefied natural gas project A common and widespread technique used at natural gas plants in Nigeria is the removal of carbon dioxide (CO2) from natural gas through chemical absorption using alkanolamine solutions. In this research, an amine sweetening process is simulated using Aspen HYSYS V10 with a typical Nigerian natural gas composition. The simulation is used to investigate four different kinds of amines and their blends (mixed amines). The investigated amines are Monoethanolamine (MEA), Diethanolamine (DEA), Diglycolamine (DGA) and Methyldiethanolamine (MDEA) while the blends are MDEA + MEA, MDEA + DEA and MDEA + DGA. Results obtained from the simulation show that the mixed amine “MDEA + MEA” with lean amine strength of 11% MEA and 39% MDEA, absorbs 99.97% of CO2 present in the gas and hence, amine blends absorb carbon dioxide from natural gas better than the individual amines. It was also concluded that increasing the composition of the primary or secondary amine while decreasing the composition of the tertiary amine in the lean amine solution (amine blend) led to an increase in the amount of CO2 being absorbed. The study provides useful information on the absorption of CO2 using alkanolamine solvents and their blends in a standard amine sweetening plant.

Tri-probe fluorescent sensor array for a wide concentration range and high precision identification of aqueous organic amines

Aqueous organic amines are threatening to organisms and ecosystem balance. Although many techniques have been used for detection, the simultaneous identification of both its type and concentration is still challenging due to its structural similarity and low environmental concentration. Sensor array is a powerful sensing technology to identify analytes via unique fingerprint patterns. However, the information from general sensor array based on the weak interaction limited its discernibility ability to similar substances. Here, we propose to design molecules with various sensing units based on strong interactions and hence rich spectral change, then construct a tri-probe sensor array for efficient fluorescent differentiation of aqueous organic amine. Different fluorescence responses to different concentrations and types of organic amines were produced by this array. Varied interaction between the probes and the amines was proved by NMR spectra analysis. The combination of probes can produce rich and complementary fluorescence changes. These unique fluorescence response patterns can be well identified and processed using hierarchical analysis (HCA) and linear discriminant analysis (LDA), enabling the 99.35% accurate differentiation of 5 concentration orders (1 μM ~ 10 mM) of 6 kinds of amines. Blind detections for samples of diethylamine, diisopropylamine in tap water and propylamine, hexylamine, trimethylamine, triethylamine in other five domestic wastewater all can be classified and distinguished successfully. The influence of temperature, pH and mental ions are also considered. This sensing method, with the feature of facile preparation, fast response, and excellent discrimination accuracy, can provide a potential option for fast quality test of water.

Reusable Co-nanoparticles for general and selective N-alkylation of amines and ammonia with alcohols.

A general cobalt-catalyzed N-alkylation of amines with alcohols by borrowing hydrogen methodology to prepare different kinds of amines is reported. The optimal catalyst for this transformation is prepared by pyrolysis of a specific templated material, which is generated in situ by mixing cobalt salts, nitrogen ligands and colloidal silica, and subsequent removal of silica. Applying this novel Co-nanoparticle-based material, >100 primary, secondary, and tertiary amines including N-methylamines and selected drug molecules were conveniently prepared starting from inexpensive and easily accessible alcohols and amines or ammonia.

The Kinetics Investigation of CO2 Absorption into TEA and DEEA Amine Solutions Containing Carbonic Anhydrase

Tertiary amines have been used as alternative absorbents for traditional primary and secondary amines in the process of carbon capture. However, the carbon dioxide (CO2) absorption rates in these kinds of amine are relatively slow, which implies greater investment and construction costs and limits the large-scale application of carbon capture. Carbonic anhydrase (CA) is considered to be an ideal homogeneous catalyst for accelerating the rate of CO2 into aqueous amine solution. In this work, CO2 absorption combining CA with two single aqueous tertiary amines, namely triethanolamine (TEA) and 2-(diethylamino)ethanol (DEEA), was studied by use of the stopped-flow apparatus over temperature ranging from 293 to 313 K. The concentrations of selected aqueous amine solution and CA used in the experiment were ranging among 0.1–0.5 kmol/m3 and 0–50 g/m3 , respectively. Compared to the solution without the addition of CA, the pseudo first-order reaction rate in the presence of CA (k0,withCA) is significantly increased. The values of k0,withCA have been calculated by a new kinetics model. The results of experimental and calculated k0,amine and k0,withCA in CO2-amine-H2O solutions were also investigated,respectively.

Ethylenediamine and Pentaethylene Hexamine Modified Bamboo Sawdust by Radiation Grafting and Their Adsorption Behavior for Phosphate

Phosphate is an important component for the growth of plants and microorganisms; however, excess phosphate causes serious eutrophication in natural waters. New potential low-loss adsorbents from natural biomass for phosphate removal are desired. Bamboo is one of the most abundant renewable cellulose resources; however, the pure bamboo cellulose is poor to adsorb phosphate. To enhance the adsorption capacity, in this work, bamboo sawdust (BS) was chemically modified by two kinds of amines. First, glycidyl methacrylate (GMA) was grafted on BS using radiation induced graft polymerization. Then, the GMA-grafted BS was further modified by a ring-opening reaction with amines, including ethylenediamine (EDA) and pentaethylene hexamine (PEHA). The amine groups were then quaternized to prepare the BS-GMA-EDA-Q and BS-GMA-PEHA-Q adsorbents. The adsorbents were characterized by FTIR, SEM, TG, and XPS analysis. The adsorption performances of the adsorbents for phosphate were evaluated through batch experiments. The adsorption by BS-GMA-EDA-Q and BS-GMA-PEHA-Q both well obeyed the pseudo-second-order kinetic model and the Langmuir isotherm model, indicating that the adsorption process was chemical monomolecular layer adsorption. The maximum adsorption capacities for BS-GMA-EDA-Q and BS-GMA-PEHA-Q calculated by the Langmuir model were 85.25 and 152.21 mg/g, respectively. A total of 1 mol/L HCl was used to elute the saturated adsorbents. A negligible decrease in adsorption capacity was found after five adsorption–desorption cycles.

Multifunctional nucleating agents with simultaneous plasticizing, solubilizing, nucleating and their effect on polyvinyl alcohol foams

Currently, preparing microcellular polymer foams by supercritical CO2 (Sc-CO2) is a newly trend and challenge. The main limitation of Sc-CO2 used in microcellular foaming industry is its solubility. In this paper, four kinds of amines (formamide, ethylenediamine, polyamide dendrimer (PAMAM) and polyhedral oligomeric silsesquioxane (POSS)) were introduced into polyvinyl alcohol (PVA) to improve the foaming behaviors. The results of differential scanning calorimetry showed that formamide and POSS could plasticize PVA to a certain extent. Through SEM analysis, formamide and ethylenediamine has a nucleating effect and improves the foaming effect. Furthermore, the content of formamide has a great influence on the foaming behavior of PVA. TG-IR analysis showed that -NH2 can react with CO2 to form -HNCOO- at normal temperature and pressure, which contributed to the diffusion of CO2 and improved the uniformity of cell size. With increasing formamide content, the cell density increased from 3.22 × 109 cm−3 to 1.79 × 1010 cm−3.

Spiropyran based recognitions of amines: UV–Vis spectra and mechanisms

As one of the important photochromic molecules, spiropyran (SP) compounds are widely used as detectors and fluorescence probes in the environment and bio-imaging field. Although great achievements have been attained for various sophisticated spiropyrans in metal ion sensing, less success is achieved in sensing organic molecules due to the weak interaction between the spiropyran and the target of the organic molecule. In this study, a spiropyran derivative containing a hydroxyl group (SPOH) was employed for the recognition of four kinds of amines via ultraviolet–visible (UV–Vis) spectra. The aliphatic primary amines, aromatic primary amines, aliphatic secondary and tertiary amines, aromatic secondary and tertiary amines were successfully distinguished according to the shapes and trends of their UV–Vis absorption spectra. The chemical reaction between aliphatic, aromatic primary amines and SPOH as well as alkalinity are two vital interaction mechanisms for the recognition process which are testified by Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR). Although SP is generally water-insoluble, it is easy to achieve soluble by fixing SPOH inside micelle or vesicle and thus the results in this study is meaningful for amine recognition utility in environments and biological systems.

Reductive amination using cobalt-based nanoparticles for synthesis of amines.

Reductive aminations are an essential class of reactions widely applied for the preparation of different kinds of amines, as well as a number of pharmaceuticals and industrially relevant compounds. In such reactions, carbonyl compounds (aldehydes, ketones) react with ammonia or amines in the presence of a reducing agent and form corresponding amines. Common catalysts used for reductive aminations, especially for the synthesis of primary amines, are based on precious metals or Raney nickel. However, their drawbacks and limited applicability inspired us to look for alternative catalysts. The development of base-metal nanostructured catalysts is highly preferable and is crucial to the advancement of sustainable and cost-effective reductive amination processes. In this protocol, we describe the preparation of carbon-supported cobalt-based nanoparticles as efficient and practical catalysts for synthesis of different kinds of amines by reductive aminations. Template synthesis of a cobalt-triethylenediamine-terephthalic acid metal-organic framework on carbon and subsequent pyrolysis to remove the organic template resulted in the formation of supported single cobalt atoms and nanoparticles. Applying these catalysts, we have synthesized structurally diverse benzylic, aliphatic and heterocyclic primary, secondary and tertiary amines, including pharmaceutically relevant products, starting from inexpensive and easily accessible carbonyl compounds with ammonia, nitro compounds or amines and molecular hydrogen. To prepare this cobalt-based catalyst takes 26 h, and the reported catalytic reductive amination reactions can be carried out within 18-28 h.

Catalytic reductive aminations using molecular hydrogen for synthesis of different kinds of amines.

Reductive aminations constitute an important class of reactions widely applied in research laboratories and industries for the synthesis of amines as well as pharmaceuticals, agrochemicals and biomolecules. In particular, catalytic reductive aminations using molecular hydrogen are highly valued and essential for the cost-effective and sustainable production of different kinds of amines and their functionalization. These reactions couple easily accessible carbonyl compounds (aldehydes or ketones) with ammonia, amines or nitro compounds in the presence of suitable catalysts and hydrogen that enable the preparation of linear and branched primary, secondary and tertiary amines including N-methylamines and molecules used in life science applications. In general, amines represent valuable fine and bulk chemicals, which serve as key precursors and central intermediates for the synthesis of advanced chemicals, life science molecules, dyes and polymers. Noteworthily, amine functionalities are present in a large number of pharmaceuticals, agrochemicals and biomolecules, and play vital roles in the function of these active compounds. In general, reductive aminations are challenging processes, especially for the syntheses of primary amines, which often are non-selective and suffer from over-alkylation and reduction of carbonyl compounds to the corresponding alcohols. Hence, the development of suitable catalysts to perform these reactions in a highly efficient and selective manner is crucial and continues to be important and attracts scientific interest. In this regard, both homogeneous and heterogeneous catalysts have successfully been developed for these reactions to access various amines. There is a need for a comprehensive review on catalytic reductive aminations to discuss the potential catalysts used and applicability of this methodology in the preparation of different kinds of amines, which are of commercial, industrial and medicinal importance. Consequently, in this review we discuss catalytic reductive aminations using molecular hydrogen and their applications in the synthesis of functionalized and structurally diverse benzylic, heterocyclic and aliphatic primary, secondary and tertiary amines as well as N-methylamines and more complex drug targets. In addition, mechanisms of reductive aminations including selective formation of desired amine products as well as possible side reactions are emphasized. This review aims at the scientific communities working in the fields of organic synthesis, catalysis, and medicinal and biological chemistry.

New insights into the role of nitrogen-bonding configurations in enhancing the photocatalytic activity of nitrogen-doped graphene aerogels

Nitrogen (N)-doped graphene aerogels (GAs) have recently emerged as a promising class of photocatalytic materials for a multitude of environmental applications. Their photocatalytic activity depends strongly on the type of N bonding configurations created in the host lattice, which in turn relies on the choice of nitrogen sources employed as molecular precursors. However, there is still no systematic assessment of the photocatalytic activity of N-doped GAs (NGAs) synthesized using different nitrogen containing precursors. Herein, we developed a series of NGAs using different kinds of amine, such as primary and secondary amines, as nitrogen precursors and rigorously evaluated their photocatalytic activity toward degradation of acridine orange under visible light irradiation. The bonding state of N atoms in the NGAs could indeed be effectively modulated by a judicious selection of an appropriate nitrogen precursor. Primary amines resulted mainly in pyridinic N structures whereas pyrrolic N was predominantly obtained from secondary amines. Irrespective of the source of nitrogen, the photocatalytic efficiency of the NGAs was directly correlated to the concentration of pyrrolic N defects in their constituent graphene building blocks. Further, the photodegradation byproducts did not present any significant antibacterial activity, reflecting the ecofriendly nature of the as-prepared novel photocatalysts.

A simple one-step ultrasonic-assisted extraction and derivatization method coupling to high-performance liquid chromatographyfor the determination of ε-aminocaproic acid and amino acids in cosmetics

Nowadays, the safety of cosmetics is a widespread concern. Amines are common cosmetic additives. Some of them such as amino acids are beneficial. Another kind of amines, however, ε-aminocaproic acid (EACA) is prohibited to add into cosmetics for its adverse reactions. In this study, a simple, rapid, sensitive and eco-friendly one-step ultrasonic-assisted extraction and derivatization (UAE-D) method was developed for determination of EACA and amino acids in cosmetics by coupling with high-performance liquid chromatography (HPLC). By using this sample preparation method, extraction and derivatization of EACA and amino acids were finished in one step in ultrasound field. During this procedure, 4-fluoro-7-nitrobenzofurazan (NBD-F)was applied as derivatization reagent. The extraction conditions including the amount of NBD-F, extraction and derivatization temperature, the ultrasonic vibration time and pH value of the aqueous phase were evaluated. Meanwhile, the extraction mechanism was investigated. Under optimized conditions, the method detection limits were 0.086–0.15 μg/L, and method quantitation limits were 0.29–0.47 μg/L with RSDs less than 3.7% (n = 3). The recoveries of EACA and amino acids obtained from cosmetic samples were in range from 76.9% to 122.3%. Amino acids were found in all selected samples and quantified in range from 1.9 ± 0.9 to 677.2 ± 17.9 μg/kg. And EACA was found and quantified with the contents of 1284.3 ± 22.1 μg/kg in a toner sample. This UAE-D-HPLC method shortened and simplified the sample pretreatment as well as enhanced the sensitivity of analytical method. In our record, only 10 min was needed for the total sample preparation process. And the method detection limits were two orders of magnitude less than literature reports. Furthermore, we reduced the consumption of solvent and minimized the usage of organic solvents, which made our method moving towards green analytical chemistry. In brief, our UAE-D-HPLC method is a simple, rapid, sensitive and eco-friendly analytical method for the determination of EACA and amino acids in cosmetics.

Composite manhole covers prepared with recycled printed circuit boards as a reinforcing filler

Waste circuit boards particles (CBPs) were utilized as a reinforcing filler to prepare bulk molding composites (BMCs) for the manufacture of composite manhole covers (CMCs) without reinforcing ribs. The effects of CBPs and conventional CaCO3 on the mechanical properties of the BMCs were comparatively determined. Compared to CaCO3, CBPs showed a higher compatibility with unsaturated polyester resin (UPR) while effectively improving the fluidity of premix and the mechanical properties of the BMC. To enhance the interfacial adhesion between the glass fiber (GF) and UPR, three kinds of amine, epoxy, and vinyl modified silanes (namely KH‐550, KH‐560, and KH‐570, respectively) were used. The surface tension (γ) of the GF significantly decreased upon modification with the coupling agents. Fourier transform infrared spectroscopy (FT‐IR) and scanning electron microscopy (SEM) characterizations revealed a strong adhesion between the GF and UPR, thereby enhancing the mechanical properties of the composite material. The BMC material showed optimal flexural strengths upon addition of KH‐560 and KH‐570 coupling agents at 4 wt%. With the aim of evaluating its mechanical performance, a constant loading test combined with an ANSYS finite element analysis was performed over the prepared CMC. According to the constant loading test, the CMC material showed a stress loading of 7.8 tons, which was close to the value obtained by ANSYS simulation. POLYM. COMPOS., 39:4532–4541, 2018. © 2017 Society of Plastics Engineers

Dual Alkali Solvent System for CO2 Capture from Flue Gas.

A novel two-aqueous-phase CO2 capture system, namely the dual alkali solvent (DAS) system, has been developed. Unlike traditional solvent-based CO2 capture systems in which the same solvent is used for both CO2 absorption and stripping, the solvent of the DAS system consists of two aqueous phases. The upper phase, which contains an organic alkali 1-(2-hydroxyethyl) piperazine (HEP), is used for CO2 absorption. The lower phase, which consists of a mixture of K2CO3/KHCO3 aqueous solution and KHCO3 precipitate, is used for CO2 stripping. Only a certain kind of amine (such as HEP) is able to ensure the phase separation, satisfactory absorption efficiency, effective CO2 transfer from the upper phase to the lower phase, and regeneration of the upper phase. In the meantime, due to the presence of K2CO3/KHCO3 in the lower phase, HEP in the upper phase is capable of being regenerated from its sulfite/sulfate heat stable salt, which enables the simultaneous absorption of CO2 and SO2/SO3 from the flue gas. Preliminary experiments and simulations indicate that the implementation of the DAS system can lead to 24.0% stripping energy savings compared to the Econamine process, without significantly lowering the CO2 absorption efficiency (∼90%).

Efficient Microwave-Assisted Functionalization of the Aurivillius-Phase Bi2SrTa2O9.

A new method of acidification and subsequent functionalization of the Aurivillius-phase Bi2SrTa2O9 (BST), using microwave irradiation, was developed. This method enables to obtain hybridized phases from layered BST. Functionalization of BST by various kinds of amines and diamines can be achieved in a few hours only, compared to much longer time (over a week) using conventional heating. Good crystallinity of the compounds is kept. In addition, a microwave-assisted preintercalation strategy was developed, allowing inserting new amines (bearing cyclic or aromatic groups) between the oxide layers previously unseen in this type of compound. This work opens new perspectives for the fast and easy functionalization of layered oxides with more elaborated molecules.

The Study of Analytical Identification on Main Monomer Compounds of Spoiled Grass Carp by High Performance Liquid Chromatography of Quadrupole Time of Flight Mass Spectrometry

Background: The change of monomer compounds of materials during preservation is becoming increasingly important in the background of food preservation. It can help to understand underlying causes of quality change of materials in preservation substantially. The objective of this study was to infer and analyze the change of main monomer compounds during spoiled Grass carp (Ctenopharyngodon Idellus), and in favor of understanding the quality change of Grass carp in preservation. Methods and materials: The spoiled Grass carp was studied as materials by High Performance Liquid Chromatography of Quadrupole Time of Flight Mass Spectrometry (HPLC-Q-TOF-MS). HPLC-Q-TOF-MS has two scan modes, positive one and negative one. Special related substances and molecular components of this characteristic fragment ion were identified by quasimolecular ion peaks and accurate molecular weight of fragment ion from high-resolution mass spectrometry. Results: 46 kinds of monomer compounds were determined in spoiled Grass carp, which have 3 kinds of non-nitrogenous compounds and 43 nitrogenous compounds. 43 nitrogenous compounds including 6 kinds of amino acids (2 kinds of α-amino acids), 10 kinds of amines, 12 kinds of amide compounds, 2 kinds of nitro compounds, 12 kinds of heterocyclic nitrogenous compounds, and 1 kinds of nitriles compound. Conclusion and suggestion: Structure of monomer compounds in fresh and perishable materials can be inferred and identificated by HPLC-Q-TOF-MS. They can be used to increase efficiency in identification and analysis of chemical component. It will be benefit for identification, evolution, and deduction of active ingredients and new compounds of fresh material in preservation.

Synthesis of hollow silica nanoparticles using poly (acrylic acid)-3,3’-diaminodipropylamine template

Abstract Synthesis of hollow silica nanoparticles using poly (acrylic acid) (PAA)-amine aggregates as nano-sized template was proposed. The PAA-amine mixtures dissolve in water, but not in ethanol, therefore the mixtures can be a template for hollow particle in ethanol and can be removed from the core–shell particle by addition of water. In order to investigate effect of amines on hollow particle formation, four kinds of amines; ethylenediamine (EDA), N,N,N’,N’-tetramethylethylenediamine (TED), 3,3’-diaminodipropylamine (DDA), triethylenetetramine (TTA), which interact with carboxylic acid of PAA were chosen. The PAA-each amine nanoparticles were formed with around 200 nm by dropping of PAA/amine mixtures in ethanol under the optimum conditions. Using the PAA-DDA template, hollow silica nanoparticles with spherical form were successfully prepared for the shortest reaction time in four hours. The primary amines and secondary amine of DDA work as not only cross-linker for PAA, but also sol–gel reacting catalyst. It can be clear from that the EDA with two primary amines also worked as sol–gel catalyst while the TED with two tertiary amines didn't. On the other hands, TTA with two primary and secondary amines also provided hollow silica nanoparticles, however, the silica shell of particles were mostly collapsed. It could be thought that the four amines of TTA promote sol–gel reaction, at the same time, high water content in the template induces molecular motion.