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In this study switchable solvent liquid phase microextraction (SSLPME) followed by GC-MS detection has been developed for preconcentration and determination of total petroleum hydrocarbons (TPHs) in water samples. The extraction technique makes use of 100 μL of a water-immiscible solvent (dipropylamine) that can be solubilized in the aqueous phase in 1:1 ratio using HCl as a reagent. Afterwards, phases separation is induced by the addition of sodium hydroxide. Optimization of the variables affecting this method was carried out in order to achieve the best extraction efficiency. The optimized conditions included: volume of the sample 5 mL, volume of extraction solvent 100 μL, and pH of sample: 12.0. Under the optimum experimental conditions, good limits of detection (0.3–1.21 µg L−1), linearities (R2 > 0.996), and repeatability of extraction (RSDs below 5.6%, n = 5) were obtained. Finally, the developed method was successfully applied to the determination of the target analytes in different types of natural water samples and acceptable recoveries (>84%) were obtained.

Highlights • Experimental vapor pressures of pure DNM, PMDETA and their aqueous solutions are reported. • The investigated temperatures are 273 K through 363 K. • The DNM binary system exhibits negative deviations in GE values. • The PMDETA system exhibit sinusoidal and positive deviations in GE values. • The 3rd order Redlich–Kister, and NRTL or UNIQUAC models have been used to correlate the (P-x-y) data. Abstract The vapour pressures of the pure components 3,3-diamino-N-methyldipropylamine (DNM) and N,N,N′,N′′,N′′-pentamethyldiethylenetriamine (PMDETA) along with the binary mixtures (DNM + water) and (PMDETA + water) were measured by means of a static apparatus at temperatures between (283 and 363) K. The data were correlated with the Antoine equation. From these data, excess Gibbs functions (GE) were calculated for several constant temperatures and fitted to four order Redlich-Kister equation using the Barker method. The binary system (DNM + water) exhibits negative deviations in GE values calculated from the vapour pressure data for all investigated temperatures and over the whole composition range. The (PMDETA + water) binary mixture shows a sinusoidal shape for GE at 283.15 K < T < 303.15 K, and a positive deviation in GE for [313.15 - 363.15] K temperature range. Additionally, the NRTL, UNIQUAC models have been used for the correlation of prediction of the total pressure. [ABSTRACT FROM AUTHOR]

In this study, a new method based on homogeneous liquid–phase microextraction was developed for the determination of methamphetamine (MA) in urine samples. Dipropylamine (DPA), as a solvent with switchable hydrophilicity, was used as the extraction solvent and can be miscible/immiscible based on variable pH values of the aqueous sample solution. The effects of operational extraction parameters such as DPA volume, temperature, the amount of added acid and base solutions, and NaCl content of the sample were investigated. Under optimal conditions the preconcentration factor, limit of detection and linearity of the method were achieved in the ranges of 98.8, 1.5 µgL −1 and 5–1500 µgL −1 , respectively. Also, within-run precision, between-run precision and robustness of the method were investigated. Finally, the proposed method was successfully applied to the analysis of MA in urine sample. [ABSTRACT FROM AUTHOR]

Refractive indices (nD), viscosities (η) and densities (p) were deliberated for the binary mixtures created by dipropyl amine with 1-octanol, 1-heptanol, 1-hexanol, 1-pentanol and tert-pentyl alcohol at temperature 298.15 K over the perfect installation extent. The function of Redlich-Kister were used to calculate and renovated of the refractive index deviations (ΔnD), viscosity deviations (ηE), excess molar Gibbs free energy (ΔG*E) and excess molar volumes(VmE). The standard errors and coefficients were respected by this function. The values of ΔnD, ηE, VmE and ΔG*E were plotted against mole fraction of dipropyl amine. In all cases the obtained ηE, ΔG*E, VmE and ΔnD values were negative at 298.15K. Effect of carbon atoms number in the chain of alcohol and hydroxyl groups' position on molecular interactions in these mixtures has also been discussed. [ABSTRACT FROM AUTHOR]

In this work, a new method based on homogeneous liquid-phase microextraction was developed for the determination of methadone and tramadol. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible/immiscible upon the addition or removal of CO2 as a reagent. The effects of operational parameters of the extraction such as volume of acceptor phase, volume of donor phase, pH of donor phase, and ionic strength of solution were investigated. Under optimal conditions, the preconcentration factors, the detection limits and the linearity of the method were achieved in the ranges of 135-138, 1.2 and 4-1000 µg L−1, respectively. Finally, the proposed method has been successfully applied to the analysis of methadone and tramadol in urine samples. In urine sample, the preconcentration factors were 118 and 122 for methadone and tramadol, respectively. Additionally, calibration curves were found to be linear in the concentration range of 8-1000 µg L−1 with the r2 values better than 0.998. In addition, limits of detection and quantification were 2.4 and 8 µg L−1, respectively, for both analytes. [ABSTRACT FROM AUTHOR]

An ionic liquid (IL) is a compound, composed of a cation, an anion and an alkyl, which has low volatility and good extraction properties. The combination of an ionic liquid and dispersive liquid-liquid microextraction with a GC-FID instrument, used for the determination of n-nitrosodipropylamine (NDPA), is an appropriate, accurate, easy and fast method. The following optimal parameters of the analysis have been established: ionic liquid [C6MIM] [PF6], dispersing solvent volume 6 µL, 6 µL volume of solvent extract and sample volume 8 ml. The correlation coefficient of this method for concentrations from 2.0 to 10.0 g/L was 0.999. The detection limit for this method is 123 g/mL with an average accuracy of 95.02 % and coefficient of variation of 0.03 % - 2.38 %. The method is developed to detect NDPA in salted fish samples of 1.12 g/L. [ABSTRACT FROM AUTHOR]

A simple, fast, sensitive, and low-cost method was developed for the quantification of nitroaromatic compounds in water samples based on CO2-assisted liquid-phase microextraction using a switchable-hydrophilicity solvent followed by gas chromatography detection. Dipropylamine was used as extraction solvent with switchable hydrophilicity that can be miscible or immiscible upon the addition or removal of CO2 as a reagent. Experimental parameters affecting the extraction efficiency such as the volume of acceptor phase, the volume of donor phase, pH of donor phase, ionic strength, and extraction time were investigated. Under the optimal conditions, detection limits and preconcentration factors were obtained in the ranges of 0.9-1.8 μg/L and 132-138, respectively. Also, the extraction recoveries of water samples were above 88%. Finally, the developed method was successfully applied to the determination of nitroaromatic compounds in real water samples. [ABSTRACT FROM AUTHOR]

Aluminophosphate and silicoaluminophosphate molecular sieves with both five (AFI) and eleven (AEL) type structures are synthesized by hydrothermal crystallization at 473 K, using tripropylamine and dipropylamine as a structure-directing template. The as-prepared AFI and AEL sieves are characterized and then assessed as sorbents for uranium (VI) from radioactive effluents. The sorption process is used to reduce the volumes of effluents and convert them into a stable solid waste. The batch experimental studies are carried out to evaluate the AEL and AFI structure effect on the removal of uranium. The AlPO 4 -5, SAPO-5, AlPO 4 -11 and SAPO-11 are applied to radioactive effluents with different activities obtained from Nuclear Research Center of Draria, Algeria. Important decontamination factor values are obtained for AFI sorbents. Thermodynamic parameters, namely, the enthalpy (Δ H ), entropy (Δ S ) and free energy (Δ G ) for each sorption process are calculated. The collected results indicated that sorbents are effective materials for the removal of uranium (VI) ions, the sorbent with AFI structure being a highly effective material for the removal of uranium (VI) ions from nuclear effluents. [ABSTRACT FROM AUTHOR]

Extracting polycyclic aromatic structures (PASs)-enriched portion from direct coal liquefaction residue (DCLR) with an energy-efficient way is significantly important for the effective utilization of DCLR. In the investigation, dipropylamine (DPA) with weak polarity was used to extract DCLR as a CO 2 -triggered switchable solvent. When the extract solution was triggered by CO 2 , the extract automatically precipitated with the yield of 22.8% of DCLR. Furthermore, adding proper amount of NaOH could successfully achieve the recovery of DPA, and the recovered solvent could be reused for extracting DCLR. According to the characterization results of the extract by multiple analytical tools, the extract mainly consisted of PASs with over 4 rings, and the average molecular model of aromatic cluster could be represented by the derivative of coronene with 8 substituent groups. The investigation proved that extraction of PASs-enriched portion using DPA from DCLR was feasible, and tremendous energetic and environmental benefits could be potentially gained given that the separation of extract and solvent as well as solvent recovery could be achieved by the non-thermal CO 2 -trigger. [ABSTRACT FROM AUTHOR]

Currently, rare earth elements (REEs) in the environmental objects are determined by neutron activation and ICP-MS methods. Capillary electrophoresis (CE) is not used for these purposes because the poor detection limits (LOD). This weakness can be overcome by multiple concentrating of the samples through the high effective sample stacking process of triply charged ions Ln 3 + . LOD for REEs were received ranged from 0.2 to 1.2 μg/l. The following composition of background electrolyte for CE determination of lanthanides was proposed: 12 mM benzimidazole, 8 mM dipropylglycolic acid, 10 mM glycolic acid, pH = 3.0. Using this background electrolyte the completely separation of REEs (Y + La + Ln without Pm) is possible for 12 min. The sample preparation procedure for CE determination of lanthanides in soil and natural water was improved and the analysis of these analytes was performed. The validity of experimental results was confirmed by AES and ICP-AES methods. [ABSTRACT FROM AUTHOR]

Curcumin is the bioactive compound of turmeric ( Curcuma longa L.) with wonderful therapeutic properties; however, is slight aqueous solubility has limited its biological applications. Advanced extraction techniques can help to overcome the low solubility of curcumin in water. In this study, extraction of curcumin from turmeric using a developed carbamate ionic liquid was investigated. N , N -Dipropyl ammonium N ′, N ′-dipropylcarbamate (DPCARB) was synthesized from dry ice and dipropylamine and used for extraction of curcumin from turmeric which resulted in extraction yield of 3.58%, at room temperature within 2 h. To enhance the curcumin extraction yield, a simple enzymatic pretreatment step was utilized. Use of a mixture of α-amylase and amyloglucosidase enzymes to destruct the turmeric cell wall prior to the extraction process remarkably improved the extraction yield to 5.73%. The superior performance of the synthesized DPCARB over conventional extraction solvents was confirmed when acetone was used for extraction of curcumin from pretreated turmeric at the same operation condition (25 °C and 2 h) which resulted in extraction yield of only 3.11%. The FTIR, UV–vis and HNMR analyses approved the selective extraction and dissolution of curcumin in DPCARB. A curcumin extract with high purity of 96% was obtained as determined by HPLC analysis. [ABSTRACT FROM AUTHOR]

Direct coal liquefaction residue (DCLR) could be extracted using dipropylamine (DPA) to afford extract with polycyclic aromatic structures, and the separation of extract and DPA as well as the recovery of DPA could be achieved by the nonthermal CO2-trigger at room temperature and atmosphere pressure, which would potentially gain huge energy savings. On the basis of preliminary single factor experiment, response surface methodology was used for optimizing DCLR extraction, and Box–Behnken experimental design was adopted, where extraction time, extraction temperature, and ratio of DPA to DCLR were chosen as the three independent variables, and extract yield was chosen as response variable. Among the three independent variables, DCLR extraction was mainly affected by extraction time and ratio of DPA to DCLR, and the two variables exhibited an interaction effect on the extract yield. The predicted extract yield would reach the peak under the optimized conditions, i.e., extraction time of 48 min, extraction temperature of 25°C, and DPA to DCLR ratio of 39 mL/g. In the practical experiment under the optimal conditions, the real extract yield was up to 29.42%, which was similar to the expected one. Response surface methodology proved to be applicable and useful for optimization of DCLR extraction. [ABSTRACT FROM PUBLISHER]

Gas-phase Ca+-dipropylamine complex has been subjected to photodissociation (400–690 nm). One reactive product, Ca+-NHC3H7, is detected only in the region of 450–528 nm, besides the evaporation fragment of Ca+, which is dominant throughout the whole spectral region we have studied. The photoreaction channel may be explained in terms of a metal insertion mechanism. The calculated results are in good agreement with the experimental observations. [ABSTRACT FROM AUTHOR]

A new gelling system based on the polymerization of hydantion epoxy resin and 3,3′-Diaminodipropylamine (DPTA) was successfully developed for fabricating silicon nitride (Si 3 N 4 ) ceramics. The effects of pH value, the dispersant content, solid volume fraction and hydantion epoxy resin amount on the rheological properties of the Si 3 N 4 slurries were investigated. The relative density of green body obtained from the solid loading of 52 vol% Si 3 N 4 slurry reached up to 62.7%. As the concentration of hydantion epoxy resin increased from 5 wt% to 20 wt%, the flexural strength of Si 3 N 4 green body enhanced from 5.3 MPa to 31.6 MPa. After pressureless sintering at 1780 °C for 80 min, the sintered samples exhibited the unique interlocking microstructure of elongated β-Si 3 N 4 grains, which was beneficial to improve the mechanical properties of Si 3 N 4 ceramics. The relative density, flexural strength and fracture toughness of Si 3 N 4 ceramics reached 97.8%, 687 MPa and 6.5 MPa m 1/2 , respectively. [ABSTRACT FROM AUTHOR]

In this work, a comprehensive study of the hydrothermal synthesis and catalytic performance of SAPO-34 templated by the isomeric dipropylamine (DPA) and diisopropylamine (DIPA) was carried out. SAPO-34 with a faster crystallization rate and lower Si content could be obtained with DIPA as the template, suggesting the better templating efficacy of DIPA than DPA. Theoretical calculations reveal that DIPA possesses more favourable non-bonding interactions with the CHA framework and the electronic configuration is of vital importance in determining the template efficacy. SAPO-34-DIPA with low silicon contents exhibits excellent performance, over which a maximum selectivity of ethylene plus propylene (87.2%) is observed. This value should be among the top ever reported. The surface Si enrichment on the crystals, which is both template- and condition-dependent, is revealed to be of significant influence in the catalytic performance. The relatively homogenous Si distribution in the crystals, lower acid concentration and weaker acid strength corporately make SAPO-34-DIPA an excellent MTO catalyst. [ABSTRACT FROM AUTHOR]

In this study, a ductile electroless Ni–P coating on the flexible printed circuit board (FPCB) was prepared in an acidic nickel plating bath. The addition of dipropylamine (DPA) in electroless plating not only improves the ductility of the Ni–P coating, but also enhances the corrosion resistance. The further analysis reveals that the ductility improvement and enhancement of corrosion resistance for the Ni–P coating may be due to the fact that the addition of DPA significantly refines the volume of columnar nodule and reduce the porosity, thus leading to the released internal stress. In addition, it was found that the nodule within the Ni–P coating grew into a columnar structure, which may be also contribute to the improvement of ductility. [ABSTRACT FROM AUTHOR]

Hierarchical SAPO-11 molecular sieve was synthesized via a seeded crystallization approach as reported in this paper. SAPO-11 molecular sieve was first synthesized in common Al 2 O 3 -P 2 O 5 -Dipropylamine-H 2 O system. Nitrogen adsorption test indicated that the synthesized SAPO-11 has additional mesoporosity with a mesopore volume being 0.09 cm 3 /g. SEM and TEM analysis indicated the formation of a core (microporous SAPO-11)/shell (mesoporous SAPO-11 aggregate) structure. With the purpose to improve the mesoporosity, SAPO-11 seed was added into the Al 2 O 3 -P 2 O 5 -Dipropylamine-H 2 O system. XRD, SEM, TEM, and nitrogen adsorption tests indicated hierarchical SAPO-11 molecular sieve with mesopore volume up to 0.40 cm 3 /g can be synthesized in Al 2 O 3 -P 2 O 5 -Dipropylamine-H 2 O system with 2–10% SAPO-11 molecular sieve as seed. SEM and TEM studies indicate the formation of SAPO-11 nanorods with ultra-small diameter (5 nm). A crystallization kinetic study indicated that 6 h is sufficient for the formation of highly crystalline hierarchical SAPO-11 molecular sieve. The texture and acidity of hierarchical SAPO-11 can be controlled by changing the crystallization time. Based on the experimental results, the formation of hierarchical SAPO-11 is an integrated effect of the burst nucleation and special rod shape of SAPO-11 nanocrystal and the role of SAPO-11 seed is promoted nucleation by increasing the surface area of the liquid–solid interface. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Alkylamines are associated with both natural and anthropogenic sources and have been detected in ambient aerosol in a variety of environments. However, little is known about the ubiquity or relative abundance of these species in Europe. In this work, ambient single-particle mass spectra collected at five sampling sites across Europe have been analysed for their alkylamine content. The aerosol time-of-flight mass spectrometer (ATOFMS) data used were collected in Ireland (Cork), France (Paris, Dunkirk and Corsica) and Switzerland (Zurich) between 2008 and 2013. Each dataset was queried for mass spectral marker ions associated with the following ambient alkylamines: dimethylamine (DMA), trimethylamine (TMA), diethylamine (DEA), triethylamine (TEA), dipropylamine (DPA) and tripropylamine (TPA). The fraction of ambient particles that contained detectable alkylamines ranged from 1 to 17 % depending on location, with the highest fractions observed in Paris and Zurich in the winter months. The lowest fractions were observed at coastal sites, where the influence of animal husbandry-related alkylamine emissions is also expected to be lowest. TMA was the most ubiquitous particle phase alkylamine detected and was observed at all locations. Alkylamines were found to be internally mixed with both sulphate and nitrate for each dataset, suggesting that aminium salt formation may be important at all sites investigated. Interestingly, in Corsica, all alkylamine particles detected were also found to be internally mixed with methanesulphonic acid (MSA), indicating that aminium methanesulphonate salts may represent a component of marine ambient aerosol in the summer months. Internal mixing of alkylamines with sea salt was not observed, however. Alkylamine-containing particle composition was found to be reasonably homogeneous at each location, with the exception of the Corsica and Dunkirk sites, where two and four distinct mixing states were observed, respectively. [ABSTRACT FROM AUTHOR]

C28H37N3O2, monoclinic, P21/c (no. 14), a=11.0454(4) Å, b=21.9125(8) Å, c=11.6544(4) Å, β=111.783(1)°, V=2619.33(16) ų, Z=4, Rgt(F)=0.0658, wRref(F²)=0.1940, T=293(2) K. [ABSTRACT FROM AUTHOR]

C28H37N3O2, monoclinic, P21/c (no. 14), a=11.0454(4) Å, b=21.9125(8) Å, c=11.6544(4) Å, β=111.783(1)°, V=2619.33(16) ų, Z=4, Rgt(F)=0.0658, wRref(F²)=0.1940, T=293(2) K. [ABSTRACT FROM AUTHOR]

Currently, in biomedicine and biotechnology fields, there is a growing need to develop and produce biomolecules with a high degree of purity. To accomplish this goal, new purification methods are being developed looking for higher performance, efficiency, selectivity, and cost-effectiveness. Affinity chromatography is considered one of the most highly selective methods for biomolecules purification. The purpose of this work is to explore a new type of a structurally simple ligand immobilized onto an agarose matrix to be used in affinity chromatography. The ligand in this study, 3,3′-diamino- N-methyldipropylamine has shown low toxicity and low cost of preparation. Moreover, the ability of the ligand to be used in affinity chromatography to purify proteins and nucleic acids was verified. An increasing sodium chloride gradient, using salt concentrations up to 500 mM, was suitable to accomplish the purification of these biomolecules, meaning that the new support allows the recovery of target biomolecules under mild conditions. Thus, the 3,3′-diamino- N-methyldipropylamine ligand is shown to be a useful and versatile tool in chromatographic experiments, with very good results either for proteins or supercoiled plasmid isoform purification. [ABSTRACT FROM AUTHOR]

We investigated the effects of gel composition and crystallization conditions on the hydrothermal synthesis of ZAPSO-43 single crystals in detail. Large single crystals of ZAPSO-43 (around 250 -c;m) with high quality were synthesized by optimizing the following synthesis conditions: crystallization temperature and duration, molar ratio of SiO 2 /Al 2 O 3 and ZnO/Al 2 O 3 , content of HF acid and organic template dipropylamine (DPA). Single-crystal X-ray diffraction measurement show that the as-synthesized ZAPSO-43 are of Fddd symmetry with lattice constants a = 9.9985 Å, b = 14.2565 Å and c = 14.5726 Å, -1; = -2; = Å3; = 90° and their unit volume is V = 2077.22 Å 3 . [ABSTRACT FROM AUTHOR]

Abstract: The functional resins containing guanylthiourea, 1-methylimidazole, 2-mercapto-1-methylimidazole, dipropylamine, 1,2-dimethylimidazole and 1-(3-aminopropyl)imidazole ligands were highly selective for the gold(I) and silver(I) from ammonia solution and they did not sorb ammine complexes of copper(II). The kinetics of gold(I) sorption on these resins was improved by immobilization of N,N-dimethylethanolamine ligands, which were responsible for increasing the hydrophilicity of the polymeric material. 1-Methylimidazole resins retained their capacity towards gold in five consecutive sorption/desorption cycles. All resins in cyanide form displayed high affinity towards gold(I) from ammoniacal solution (100g/L NH3·H2O, 5.00g/L (NH4)2SO4). The sorption degrees of gold were 99.5%. [Copyright &y& Elsevier]

Abstract: Densities, ρ, and speeds of sound, u, of {2-heptanone+dipropylamine (DPA), +dibutylamine (DBA), or +triethylamine (TEA)} systems have been measured at (293.15, 298.15, and 303.15)K and atmospheric pressure using a vibrating tube densimeter and sound analyzer Anton Paar model DSA-5000. The ρ and u values were used to calculate excess molar volumes, , and the excess functions at 298.15K for the speed of sound, u E, the thermal expansion coefficient, , and for the isentropic compressibility, . Structural effects increase with the ketone size in mixtures with a fixed amine. , , and increase when DPA is replaced by DBA in systems with a given ketone as: (i) interactions between unlike molecules are more easily created in solutions containing the shorter amines; (ii) this effect predominates over that related to the disruption of the amine–amine interactions. Contributions to from the creation of interactions between unlike molecules and from the breaking of the amine–amine interactions are both lower in absolute value for TEA systems when are compared to those of DPA solutions. The increasing positive values observed when DPA is replaced by TEA in solutions with propanone or 2-butanone reveal that the former contribution is less relevant, and more important for the DPA mixtures. The opposite behavior for 2-heptanone systems is attributed to the existence of structural effects when this ketone is mixed with TEA. These general trends are confirmed by the treatment of the mixtures using the PFP theory, and the internal pressure concept. [Copyright &y& Elsevier]

We performed scanning tunneling microscope (STM) studies to observe the surface electronic structure of the following semiconducting charge-transfer complexes: dipropylamine-tetracyanoquinodimethane [DPA(TCNQ)2], triethylammonium [TEA (TCNQ)2], and N-ethylmorpholinium [HEM(TCNQ)2], which all possess the molecularly flat bc surface terminated predominately with the quasi-one-dimensional (1D) TCNQ-0.5 anion chains or the corresponding DPA+, TEA+, and HEM+ cations contributing a lesser fraction. On the bc surfaces terminated with TCNQ-0.5 anions for all crystals, the 4kF[DPA(TCNQ)s] or 2kF [TEA(TCNQ)2 and HEM(TCNQ)2] charge density wave (CDW) driven by the spin-Peierls or Peierls instability for the quasi-1D TCNQ-0.5 chains, respectively, which occur already within the bulk, were probed by use of STM on the crystal surfaces. In that the surface lattice constants obtained from CDW are in good agreement with the bulk ones obtained by x-ray diffraction, such CDWs are commensurate. This modulation of the electric structure is so distinct that the geometric corrugation of individual TCNQ anions was hardly traced during our STM measurements. On the bc surfaces terminated with DPA+, TEA+, and HEM+ cations, the STM images with submolecular resolution represent the geometric corrugation of individual molecular cations, and the surface lattice constants obtained deviate greatly from that of the x-ray crystal structures, indicating self-reassembling of the surface cations. [ABSTRACT FROM AUTHOR]

Abstract: We report the effects of gel composition and crystallization conditions on the hydrothermal synthesis of large silicon substituted AlPO4-11 single crystals (SAPO-11). Perfect large SAPO-11 single crystals with a typical dimension of 40×80×180μm3 were synthesized by optimizing the following synthesis conditions: crystallization temperature and duration, molar ratio SiO2/Al2O3, amount of the organic template dipropylamine (DPA) and HF. Single-crystal X-ray diffraction measurement showed that the as-synthesized SAPO-11 single crystals are of space group Icm2 symmetry with lattice constants a =13.384Å, b =18.60Å and c =8.414Å, and their unit cell volume is V =2094Å3. [ABSTRACT FROM AUTHOR]

Abstract: Densities, ρ, and speeds of sound, u, of 2-propanone+dipropylamine, + dibutylamine or + triethylamine systems have been measured at (293.15, 298.15 and 303.15) K and atmospheric pressure using a vibrating tube densimeter and sound analyser Anton Paar model DSA-5000. The ρ and u values were used to calculate excess molar volumes, V E, and the excess functions at 298.15K for the thermal expansion coefficient, α P E, and for the isentropic compressibility, K S E at 298.15K. V E, K S E and α P E are positive magnitudes. When replacing dipropylamine by dibutylamine or triethylamine in the studied mixtures, the excess functions increase. This may be ascribed to the interactions between unlike molecules which are more important in the former solutions. From the comparison with similar data obtained for 2-propanone+aniline, + N-methylaniline, or + pyridine systems, it is concluded that interactions between unlike molecules are stronger in mixtures containing aromatic amines. Free volume effects are present in solutions with dipropyl or dibutylamine as the V E curves are shifted towards higher mole fractions of 2-propanone. [Copyright &y& Elsevier]

Abstract: Decomposition mechanism of dipropylamine (DPA) molecules in the channels of AlPO4-11 and Si-incorporated AlPO4-11 (SAPO-11) zeolite crystals was investigated by mass spectrometry, with the aim to fabricate high-density 0.3-nm single-walled carbon nanotubes (SWNTs). In comparison with neutral AlPO4-11, the organic template DPA is bonded to SAPO-11 framework by strong chemical interaction. As a result, a significant amount of hydrocarbon molecules are trapped in the channels during carbonization process. In addition, the SAPO-11 framework plays an important catalytic role in the pyrolysis and conversion of the organic molecules to SWNTs within the crystal channels, owing to the Bønsted acid sites. The resulting SWNTs have higher density than those fabricated without Si doping, evidenced by the clear and strong radial-breathing modes in Raman spectra. [Copyright &y& Elsevier]

Complex formation in systems iron phthalocyanine — aliphatic amines was studied and stability constants for these complexes were calculated. It was shown that stability constant depends on the steric factor, when basicity of amine slightly affect on the complex formation. Stability constant values for the complexes increase in the row t-BuNH2, i-PrNH2, Pip=Mf, n-C5?11NH2. The correlation between lgK values as well as metal-to-ligand charge transfer (MLCT) position in absorption spectra and steric characteristics of axial ligand was ascertained. Complex formation was not observed in the systems of iron phthalocyanine with diethyl or dipropyl amine. [ABSTRACT FROM AUTHOR]

The respiratory effects resulting from stimulation of 5-HT1A receptors were studied in spontaneously breathing rats that were: (i) neurally intact and subsequently bilaterally vagotomized; (ii) subjected to bilateral midcervical vagotomy followed by supranodosal vagotomy; (iii) midcervically vagotomized and treated by carotid sinus/body denervation; or (iv) subjected to infra- and supranodosal vagotomy followed by pharmacological blockade of 5-HT1A receptors. An intravenous bolus of the 5-HT1A receptor agonist 8-hydroxy-dipropylaminotetralin (8-OH-DPAT, 10 μg kg−1) evoked increases in both breathing rate and tidal volume. After section of the midcervical and supranodosal vagi, 8-OH-DPAT challenge still increased the respiratory rate and tidal volume. Carotid sinus/body denervation did not reduce the augmentation of the tidal volume, but prevented the increase in breathing rate. Blockade of 5-HT1A receptors with intravenous doses of 1-(2-metoxyphenyl)-4-[4-(2-phthalimido) butyl] piperazine (NAN 190; 20 μg kg−1) abolished all respiratory effects of 8-OH-DPAT challenge. In all the neural states, 8-OH-DPAT evoked a significant fall in mean arterial blood pressure. Pretreatment with NAN 190 reduced baseline values of mean arterial pressure and prevented 8-OH-DPAT-induced hypotension. These results indicate that: (i) 8-OH-DPAT-evoked activation of 5-HT1A receptors increases breathing rate and tidal volume, which persists after section of the lung vagi and the nodose ganglia, but only the increase in breathing rate was abolished by carotid sinus/body denervation; and (ii) 8-OH-DPAT hyperventilatory and hypotensive responses result from the excitation of presumed 5-HT1A carotid receptors and the central 5-HT1A-expressing neurones. [ABSTRACT FROM AUTHOR]

Abstract: The spun film of zinc(II) 1,4,8,11,15,18,22,25-octabutoxy-phthalocyanine was investigated as optical sensor for amine vapors. The enhancement of the Q band absorbance at 750nm was attributed to the coordination of amine to the central zinc ion. Effects of the amine structure on the sensing properties were investigated to elucidate the sensing mechanism. Sensitivity and response speed of the sensor are influenced by the gas phase basicity and the steric hindrance effect of the amine. Among the six-carbon amines studied, n-hexylamine shows the highest sensitivity and the fastest response, followed by dipropylamine, and then the tertiary triethylamine. For primary amines, the sensitivity and the response speed increase as length of the alkyl chain increases. The response time for 1000ppm n-hexylamine is 11s, and that for methylamine is 440s. The response signal ΔA 750 is found to be proportional to the amine concentration for n-butylamine in the 5–40ppm range, with the sensitivity S =0.0009/ppm. [Copyright &y& Elsevier]

Even though trifluralin (α,α,α-2,6-dinitro-N-N-dipropyl-p-toluidine) is effective for the treatment of experimental Chagas disease, more preclinical toxicity studies need to be performed. Cell toxicity of trifluralin was studied in Hep-G2 and Vero C76 cells treated with 50 and 150 µM trifluralin. The results show that duplication time, amount of cellular protein and cell protein/DNA values were normal. Histological, haematological and chemical parameters were measured in CF1 mice after oral trifluralin administration. Acute toxic effects were assayed by administration of 50 or 200 mg/kg body weight daily for 30 days, and chronic effects by administration of 200 mg/kg body weight once a week for 90 days (n = 20). In the acute scheme treatment, hepatic (glutamic-pyruvic, glutamic-oxalacetic and alkaline phosphatase activities; proteins and albumin plasma concentrations) and pancreatic (amylase, glycaemia) functions were normal. Mean corpuscular volume, haemoglobin and haematocrit decreased. Creatine phosphokinase, lactate dehydrogenase and glutamic-oxalacetic activity increased, suggesting lesion in myocardial tissue. Histology was normal, excepting for the heart (mild myocarditis). Similar results were observed in acutely treated animals. There were no differences in body weight gain for treated mice compared to controls. In view of the published therapeutic effects of trifluralin on CF1 Chagas disease model and considering the present results, trifluralin seems to be a moderately toxic drug with a potential selective effect on the myocardium. [ABSTRACT FROM AUTHOR]