1,2-环己二醇标准摩尔燃烧焓和定压热容测定

采用GR-3500型氧弹量热计实验测定了顺式-1,2-环己二醇和反式-1,2-环己二醇的标准燃烧焓,分别为-3507.043kJ/mol和-3497.8kJ/mol,并用萘作标准物验证测试仪器,其实验测定值与文献值相对误差为0.053%,同时推算出环己二醇的标准摩尔生成热,分别为568.997kJ/mol(顺式)和578.240kJ/mol(反式)。用NETZSCHDSC204型差示扫描量热仪测定了1,2-环己二醇的定压热容,拟合出环己二醇摩尔定压热容与温度之间的函数关系;同时还测定了1,2-环己二醇的熔点和熔化热,为该产品的新工艺开发、工程设计和工业化生产提供了基础数据。     

萘普生比热容和燃烧焓的测定

用XRY-1C氧弹式量热计测定了萘普生的标准摩尔燃烧焓,其值为-7 026.5 kJ/mol,并用萘作标准物检测了仪器的可靠性,标准摩尔燃烧焓测定值与文献值的绝对误差为4.53 kJ/mol,相对误差为0.088%。结合热力学原理,计算出萘普生的标准摩尔生成焓为-483.5 kJ/mol。用DSC-60差示扫描量热仪测定了萘普生和苯甲酸在不同温度范围内的比定压热容,并建立起比定压热容随温度的变化关系,为萘普生的工艺开发、工程设计以及工业化生产提供了热力学基础数据。     

碳酸甲苯酯标准摩尔燃烧焓的测定

以碳酸二甲酯和苯酚为原料通过酯交换反应合成了碳酸甲苯酯,经提纯得到纯度大于99.5%的产品,采用GR3500型弹式量热计测定了碳酸甲苯酯的标准摩尔燃烧焓为-3868.6 kJ/mol,与采用基团贡献法的理论计算值之间的绝对误差仅为1.4 kJ/mol,相对误差仅为0.04%,由此证明实验结果是可靠的,测定结果对于碳酸甲苯酯及相关下游产品的工艺开发、工程设计、工业化生产提供了重要的热力学数据。     

多羟基二苯并呋喃稳定性和摩尔定压热容研究

选取密度泛函理论(DFT)中的B3LYP计算方法,采用6-311G**基组,运用Gaussian 03程序对多羟基二苯并呋喃(PHODFs)羟基不同取向产生的不同构象的分子结构进行了全优化计算,得到了标准状态下各分子的热力学数据。通过对总能量ET的比较发现:在PHODFs中存在3类氢键,并采用电子密度拓扑分析验证了氢键的存在。在此基础上计算了135个分子对应的最稳定构象的分子结构,计算了从200—1 000 K的摩尔定压热容(C,p m),并用最小二乘法求得Cp,m与温度(T,T-1,T-2)之间的相关方程,相关系数R2均为1.000,所建模型可以用来预测相应参数。     

Determination of hydrogen content, gross heat of combustion, and net heat of combustion of diesel fuel using FTIR spectroscopy and multivariate calibration

The precise determination of the heat of combustion is of great importance for trading automotive diesel. The net heat of combustion (NHC) of fuel is related to the hydrogen elemental composition of fuel as obtained by elemental analysis. Heat of combustion expressed as gross heat of combustion (GHC) and net heat of combustion (NHC) have been predicted from data obtained by proximate analysis (density, ash, water and sulphur content) (ASTM D4868). GHC was obtained using bomb calorimetry (ASTM D240). The results of ASTM D4868 and ASTM D240 were found in good agreement. GHC and NHC fall within the relatively narrow range 45.24-46.08 and 41.91-43.27 MJ/kg, respectively. GHCs of tested diesel samples are, on average, about 7% greater than NHCs. The present paper also present a simple analytical method for determination of hydrogen content, GHC, and NHC of automotive diesel fuel using FTIR spectroscopy and partial-least squares calibration (PLS-1). PLS-1 had a high prediction power for prediction of hydrogen from FTIR spectra of diesel samples. The spectral ranges used in calibration were 400-670 and 2846-2970 cm⁻¹. On the other hand, classical least squares calibration (CLS) was found invalid for determination of hydrogen content in diesel. The results obtained by the proposed analytical method were almost to those obtained by ASTM D4868 and ASTM D240. PLS-1 method, offers a simple and reliable analytical method for quantification of hydrogen content in diesel samples without running expensive analysis like those carried out using carbon, hydrogen, and nitrogen (CHN) instruments.     

黄磷燃烧热能的回收与利用综述

通过对国内磷酸需求的分析 ,从环境及经济的角度提出了黄磷燃烧热能的回收与利用的课题 ,并就该课题的国内、国外技术进行了综述与讨论     

Investigation on specific heat capacity and thermal behavior of sodium hydroxyethyl sulfonate

The thermal decomposition process was studied by the TG–DTA analyzer. The results show that the decomposition process of sodium hydroxyethyl sulfonate consisted of three stages: the mass loss for the first, the second and third stages may be about the groups of CH_3CH_2OH, CH_3CHO and SO_2 volatilized, respectively. The decomposition residuum of three stages was analyzed by FT-IR, and the results of FT-IR agreed with the decomposition process predicted by theoretical weight loss. The specific heat capacity of sodium hydroxyethyl sulfonate was determined by differential scanning calorimetry(DSC). The melting temperature and melting enthalpy were obtained to be 465.41 K and 25.69 kJ·mol~(-1), respectively. The molar specific heat capacity of sodium hydroxyethyl sulfonate was determinated from 310.15 K to 365.15 K and expressed as a function of temperature.     

Methane dry reformer by application of chemical looping combustion via Mn-based oxygen carrier for heat supplying and carbon dioxide providing

In this study, the production of H₂ utilizing chemical looping combustion (CLC) in a methane dry reformer assisted by H₂ perm-selective membranes in a CLC-DRM configuration has been investigated. CLC via employment of a Mn-based oxygen carrier generates large amounts of heat in addition to providing CO₂ as the raw material for the dry reforming (DR) reaction. The main advantage of the CLC-DRM configuration is the simultaneous capturing and consuming of CO₂ as a greenhouse gas for H₂ production.A steady state one dimensional heterogeneous catalytic reaction model is applied to analyze the performance and applicability of the proposed CLC-DRM configuration. Simulation results show that CH₄ is completely consumed in the fuel reactor (FR) of the CLC-DRM and pure CO₂ is captured by condensation of H₂O. Also, CH₄ conversion and H₂ yield reach 73.46% and 1.459 respectively at the outlet of the DR side in the CLC-DRM. Additionally, 4562 kmol h⁻¹ H₂ is produced in the DR side of the CLC-DRM.Finally, results indicate that by increasing the FR feed temperature up to 880 K, CH₄ conversion and H₂ production are enhanced to 81.15% and 4790 kmol h⁻¹ respectively.     

Effect of heat transfer on the distributions of OH and CH radicals in the boundary layer with ethanol combustion

The reasons for formation of superequilibrium concentrations of radicals are studied by means of joint consideration of experimental data on the distributions of CH and OH molecules formed during diffusion combustion of ethanol and data on heat transfer in the chemical reaction region. The air flow velocity near the stagnation point in experiments with combustion is 0.7 m/sec, and the flow velocity along a flat plate is 10 m/sec (the turbulence levels are 1 and 18%). Mutual locations of specific features in the distributions of the heat-release rate and temperature are analyzed and compared with the distributions of OH and CH radicals. For all turbulence levels and flow velocities considered, the maximum concentration of radicals is reached on the boundaries of the heat-release region, whose locations are determined by molecular transport mechanisms. It is demonstrated that this conclusion is applicable to experimental data on diffusion combustion of a submerged hydrogen jet in air. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 6, pp. 3–11, November–December, 2008.     

高温固硫矿物3CaO·3A12O3·CaSO4的热力学数据的计算与验证

Calcium sulfoaluminate,3CaO·3Al2O3·CaSO4,has been widely recognized in the realms of high-temperature combustion and cement chemistry.However,the lack of relevant thermodynamic data limits the progress of its research and development.Through comparative calculations using several different approaches,we obtain the thermochemical properties of 3CaO·3Al2O3·CaSO4 in this work,such as its standard formation enthalpy,Gibbs free en- ergy of formation,entropy,and molar heat capacity.With these fundamental data,thermodynamic calculations become possible for reactions involving this mineral.It is found that some reactions proposed in literature to generate this mineral may not proceed thermodynamically.     

热定型对嵌段聚醚酯弹性纤维结构与性能的影响

研究了热定型时间、温度和方式对嵌段聚醚酯弹性纤维的结构和性能的影响 ,采用 DSC、X-射线衍射测定了纤维热定型前后结晶结构及结晶度的变化 ,同时测定了纤维的断裂强度、断裂伸长、回弹率和热水收缩率的变化 ,结果表明 ,热定型处理使嵌段聚醚酯纤维的结晶结构发生了变化并使结晶度提高 ,从而提高了纤维的回弹性能和力学性能 ,纤维的热水收缩率与氨纶相当     

Effect of oxirane groups on curing behavior and thermal stability of vinyl ester resins

The effects of oxirane groups in vinyl ester (VE) resin and reactive diluent on curing characteristics and thermal behavior of cured resins are described. Stoichiometric (0.5:1, sample A) as well as nonstoichiometric (0.5:0.85, sample B) ratios of the diglycidyl ether of bisphenol-A (DGEBA) and methacrylic acid (MA) were used for the synthesis of VE resins. Resin sample B had more residual epoxy groups because of the stoichiometric imbalance of the reactants. VE resins thus obtained were diluted with methyl methacrylate (MMA; 1:1, w/w), and controlled quantities of epoxy groups were introduced by partial replacement of MMA with glycidyl methacrylate (GMA), keeping the overall ratio of resin and reactive diluent constant. Increase of GMA content in resin A or B resulted in a decrease in gel time, indicating that the curing reaction is facilitated by the presence of epoxy groups. An increase in initiator content also reduced the gel time. In the differential scanning calorimetry (DSC) scans, a sharp curing exotherm was observed in the temperature range 107 ± 3–150 ± 1 °C. The onset temperature (T_onset) and peak exotherm temperature (T_exo) decreased with increase in GMA content. Heat of curing (ΔH) also increased with increase in GMA content. A broad exotherm was observed after the initial sharp exotherm that was attributed to the etherification reaction. Cured VE resins were stable up to 250–260 °C, and started losing weight above this temperature. Rapid decomposition was observed in the temperature range 400–500 °C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 416–423, 2001     

Studies on the effect of epoxide equivalent weight of epoxy resins on thermal,mechanical, and chemical characteristics of vinyl ester resins

Three samples of vinyl ester resins (VERs) were synthesized using bisphenol‐A‐based epoxy resins of varying epoxide equivalent weights (EEW) and acrylic acid in presence of triphenylphosphine as a catalyst at 80 ± 2°C. The cresyl glycidyl ether was used as reactive diluent during the synthesis of VERs. A suitable reaction mechanism was proposed and discussed for the reactions involving epoxide group and acid groups. This was further confirmed by infrared spectroscopic analysis. The maximum peak temperature from DSC were at 106.05°C, 114.20°C, and 128.86°C for benzoyl peroxide initiated VERs viz. samples V₁C_V, V₂C_V, and V₃C_V, respectively, increased with the increase of EEW of the parent epoxy resin. It has also been found that the films of VER having highest EEW of bisphenol‐A epoxy resin showed best chemical resistance amongst all other VERs in this study. The mechanical properties such as hardness and flexibility also showed a similar trend. The thermal stability was found to decrease with the increase of EEW of bisphenol‐A epoxy resin in the VERs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and characterization of novel film adhesives based on cyanate ester resin for bonding advanced radome

In this paper, the novel film adhesives based on phenolphthalein poly(ether sulfone) (PES-C) and epoxy (EP) modified cyanate ester resin (CE) were prepared for bonding an advanced radome. The film adhesives are convenient for applying to manufacture, possessing good adhesion strength, thermal durability and excellent dielectric property. The curing behaviors were confirmed by differential scanning calorimetry (DSC), showing that the main reaction pathways are not varied with adding PES-C but the reaction rates are evidently accelerated, and the film adhesives can be well cured at lower temperature of 177 °C. The adhesion strength was evaluated in lap shear strength and peel strength, indicating that the better adhesion strength is obtained with increasing in PES-C. The maximum value of lap shear strength is 33 MPa at room temperature. The thermal durability was determined by thermal aging tests of lap shear specimens, showing that the decrease in strength gets faster with adding PES-C, and the usability of film adhesives over 2000 h at 200 °C. The dielectric properties were measured by dielectric resonator methods, finding that the introduction of PES-C brings a positive effect on dielectric properties. The lowest value of determined dielectric loss is 0.0075 at 10 GHz.     

Excess molar enthalpies for the binary and ternary mixtures of ether compounds (di-isopropyl ether, di-butyl ether, propyl vinyl ether) with ethanol and isooctane at 298.15 K

Excess molar enthalpy (H ^E ) data at 298.15 K are reported for the binary systems di-isopropyl ether (1)+ethanol (2), di-isopropyl ether (1)+isooctane (2), ethanol (1)+isooctane (2), di-butyl ether (1)+ethanol (2), di-butyl ether (1)+isooctane (2), propyl vinyl ether (1)+ethanol (2) and propyl vinyl ether (1)+isooctane (2). These data were obtained by using an isothermal flow calorimeter. The experimental binary H ^E data were well correlated with the Redlich-Kister model, and infinitely dilute partial excess molar enthalpies for each binary were calculated with the fitted Redlich-Kister parameters. Additionally, the isoclines of H ^E for ternary systems di-isopropyl ether (1)+ethanol (2)+isooctane (3), di-butyl ether (1)+ethanol (2)+isooctane (3) and propyl vinyl ether (1)+ethanol (2)+isooctane (3) at 298.15 K were calculated by using the Radojkovič equation. H ^E for all the measured systems in this work shows that mixing is endothermic.     

Synthesis and characterization of an amphiphilic hyperbranched poly(amine‐ester)‐co‐D,L‐lactide (HPAE‐co‐PLA) copolymers and their nanoparticles for protein drug delivery

A series of hyperbranched poly(amine‐ester)‐co‐D ,L ‐lactide (HPAE‐co‐PLA) copolymer were synthesized by ring‐opening polymerization of D ,L ‐lactide with Sn(Oct)₂ as catalyst to a fourth generation branched poly(amine‐ester) (HPAE‐OHs4). The chemical structures of copolymers were determined by FTIR, ¹H‐NMR, ¹³C‐NMR, and TGA. Double emulsion (DE) and nanoprecipitation (NP) method were used to fabricate the nanoparticles of these copolymers encapsulating bovine serum albumin (BSA) as a model. DSC thermo‐grams indicated that the nanoparticles with BSA kept stable below 40°C. Different factors which influence on particular size and encapsulation efficiency (EE) were investigated. Their EE to BSA could reach 97.8% at an available condition. In vitro release behavior of NPs showed a continuous release after a burst release. The stability maintenance of BSA in the nanoparticle release in vitro was also measured via circular dichroism and fluorescence spectrometry. The results showed that the copolymer nanoparticles have a promising potential in protein delivery system. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of vitrification pressure on radius of gyration,specific heat and density of amorphous polymers

The effects of vitrification pressure (to 500 MPa) and temperature (to 180°C) on the radius of gyration (as determined by small-angle neutron scattering), specific heat, and density were measured for polystyrene and poly(methyl methacrylate). The radius of gyration increased slightly (5 × 10^?3/°C) in both polymers; this increase is near the experimental uncertainty in the measurements. The small observed values are due to either small intrinsic effects of temperature or pressure on the conformation or competing effects of temperature and pressure. Density and specific heat showed changes which have been observed before and are attributed to intermolecular factors.     

Thermal performance and entropy generation for nanofluid jet injection on a ribbed microchannel with oscillating heat flux: Investigation of the first and second laws of thermodynamics

In current numerical study, forced flow and heat transfer of water/NDG (Nitrogen-doped graphene) nanofluid in nanoparticles mass fractions (φ) of 0, 2% and 4% at Reynolds numbers (Re) of 10, 50, 100 and 150 are simulated in steady states. Studied geometry is a two-dimensional microchannel under the influence of nanofluid jet injection. Temperature of inlet fluid equals with T_c=293 K and hot source of microchannel is under the influence of oscillating heat flux. Also, in this research, the effect of the variations of attack angle of triangular rib (15°, 30°, 45° and 60°) on laminar nanofluid flow behavior inside the studied rectangular geometry with the ratio of L/H=28 and nanofluid jet injection is investigated. Obtained results indicate that the increase of Reynolds number, nanoparticles mass fraction and attack angle of rib leads to the increase of pressure drop. By increasing fluid viscosity, momentum depreciation of fluid in collusion with microchannel surfaces enhances. Also, the increase of attack angle of rib at higher Reynolds numbers has a great effect on this coefficient. At low Reynolds numbers, due to slow motion of fluid, variations of attack angle of rib, especially in angles of 30°, 45° and 60° are almost similar. By increasing fluid velocity, the effect of the variations of attack angle on pressure drop becomes significant and pressure drop figures act differently. In general, by using heat transfer enhancement methods in studied geometry, heat transfer increases almost 25%.     

Biodegradable polymers based on renewable resources. V. Synthesis and biodegradation behavior of poly(ester amide)s composed of 1,4:3,6‐dianhydro‐D‐glucitol, α‐amino acid,and aliphatic dicarboxylic acid units

A series of poly(ester amide)s were synthesized by solution polycondensations of various combinations of p‐toluenesulfonic acid salts of O,O′‐bis(α‐aminoacyl)‐1,4:3,6‐dianhydro‐D ‐glucitol and bis(p‐nitrophenyl) esters of aliphatic dicarboxylic acids with the methylene chain lengths of 4–10. The p‐toluenesulfonic acid salts were obtained by the reactions of 1,4:3,6‐dianhydro‐D ‐glucitol with alanine, glycine, and glycylglycine, respectively, in the presence of p‐toluenesulfonic acid. The polycondensations were carried out in N‐methylpyrrolidone at 40°C in the presence of triethylamine, giving poly(ester amide)s having number‐average molecular weights up to 3.8 × 10⁴. Their structures were confirmed by FTIR, ¹H‐NMR, and ¹³C‐NMR spectroscopy. Most of these poly(ester amide)s are amorphous, except those containing sebacic acid and glycine or glycylglycine units, which are semicrystalline. All these poly(ester amide)s are soluble in a variety of polar solvents such as dimethyl sulfoxide, N,N‐dimethylformamide, 2,2,2‐trifluoroethanol, m‐cresol, pyridine, and trifluoroacetic acid. Soil burial degradation tests, BOD measurements in an activated sludge, and enzymatic degradation tests using Porcine pancreas lipase and papain indicated that these poly(ester amide)s are biodegradable, and that their biodegradability markedly depends on the molecular structure. The poly(ester amide)s were, in general, degraded more slowly than the corresponding polyesters having the same aliphatic dicarboxylic acid units, both in composted soil and in an activated sludge. In the enzymatic degradation, some poly(ester amide)s containing dicarboxylic acid components with shorter methylene chain lengths were degraded more readily than the corresponding polyesters with Porcine pancreas lipase, whereas most of the poly(ester amide)s were degraded more rapidly than the corresponding polyesters with papain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2721–2734, 2001