SYNTHESIS OF HIGH MOLECULAR WEIGHT POLY(p-PHENYLENE SULFIDE) RESINS

This is a method of producing crystal linear high molecular weight poly p-phenylene sulfide (HMWPPS) resins by mixing hydrogen sulfide which is produced from the acid gas of desulphurization factory of natural gas, sodium hydroxide, p-dichlorobenzene and additive sodium phosphate, and carrying out the polycondensation in hexamethyl phosphoryl triamide (HPTA) solvent for 4 to 6 h under normal pressure. This method has obvious advantages as simple equipment, easy operation, high activity, stable solvent, high product yield, low cost and it is suitable for large-scale industrial production.     

A simple and controlled oxidative decontamination of sulfur mustard and its simulants using ozone gas

A simple and efficient oxidative decontamination method was developed for sulfur mustard (HD), a potential chemical warfare agent. The method involves treatment of chemical warfare agent HD and its simulants, i.e., dimethyl sulfide, diethyl sulfide, and 2-chloroethyl ethyl sulfide with ozone gas at ambient conditions in acetonitrile solvent. Ozone gas readily oxidizes sulfur mustard in a controlled manner to give its corresponding nontoxic sulfoxide. This transformation is selective and takes place even at subzero temperatures. The oxidation products of HD and its simulants were monitored and quantified by gas chromatography and gas chromatography–mass spectrometry.     

Generating gas flows with a constant trace concentration of hydrogen sulfide

The dynamic gas extraction of hydrogen sulfide from aqueous solutions of sodium sulfide was studied theoretically and experimentally. The effects of the number of bubblers, the concentration of sodium sulfide, and the pH of solution on the concentration of hydrogen sulfide in the generated gas flow were found. The proposed method for generating gas flows with a constant trace concentration of hydrogen sulfide can be used for calibrating the verifying instruments for gas analysis.     

无机钠离子电池固体电解质研究进展

地球上钠资源储量丰富、成本低廉,使得钠电池吸引了越来越多研究者的关注。传统的基于有机溶剂电解液体系的钠电池在安全方面存在不足。固态钠离子电池能够有效解决安全的问题,增加电池的安全性能。固态钠离子电池是一种很有前景的储能方式。钠离子固体电解质主要有Na-β-Al_2O_3、钠超离子导体(NASICON)、硫化物、聚合物以及硼氢化物这几类。无机固体电解质相对于聚合物固体电解质,离子电导率有优势。本文总结了三种常见的无机钠离子固体电解质:Na-β-Al_2O_3、NASICON、硫化物的研究进展,从离子电导率和界面稳定性等方面阐述了近年来的发展。     

有机磷化合物的研究(Ⅳ)——S-烷基S-(N-取代氨基羰甲基)乙基三硫代磷酸酯的合成

应用乙基二硫化磷可制取O-烷基乙基二硫代膦酸酯^[1];从而可以进行此类杀虫剂的合成^[2].G.Schrader先后合成S,S-(3,4二氯苯基)三硫代乙基膦酸酯及S-乙基S-乙硫乙基三硫代甲基膦酸酯,生物试验证明它们是很好的杀虫剂,且对温血动物毒性低^[3].我们对乙基三硫代膦酸酯的制备进行了一些试验,最后以乙基三硫代膦酸铵和N-取代α-氯代乙酰胺反应,制取S-烷基S-(N-取代氨基羰甲基)乙基三硫代膦酸酯.     

Determination of Low Level Sulfides in Environmental Waters by Automated Gas Dialysis/Methylene Blue Colorimetry

Abstract

A sensitive and rapid automated method has been developed for the selective analysis of acid extractable sulfide in environmental samples by combining gas dialysis separation techniques with methylene blue detection procedures. Acid extractable sulfide is separated from the sample matrix by the gas dialysis membrane and subsequently trapped in a dilute sodium hydroxide receiving stream. This stream is reacted with N, N-dimethyl-p-phenylenediamine and ferric chloride to produce methylene blue which is then quantitated colorimetrically at 660 nm. For standards and nonturbid environmental samples, there is good agreement between the results obtained by this procedure and the standard methylene blue method. The effect of interferences on the accurate determination of sulfide by both methods was also examined and it was found that cupric ions significantly interfered with sulfide estimation. To obtain adequate sulfide recoveries in tap water and environmental samples ascorbic acid must be added as an antioxidant. A detection limit of 2 μg/L of sulfide has been obtained using this procedure.     

阴离子表面活性剂聚二硫二丙烷磺酸钠的合成

利用硫化钠与硫磺反应制备二硫化钠,然后将二硫化钠与1,3-丙磺酸内酯反应,合成了一种可作为电镀添加剂的阴离子表面活性剂——聚二硫二丙烷磺酸钠(SPS)。采用核磁共振氢谱对合成产物进行结构表征,确认了产物结构及产率。通过正交试验研究了产物产率与反应物配比、反应温度、溶剂加入量等因素之间的关系,找出了最优合成条件:第一步合成二硫化钠的反应中,硫化钠/硫磺物质的量比为1∶1.3,温度55℃,加水量18 mL;第二步合成SPS的反应中,1,3-丙磺酸内酯/硫化钠物质的量比为1.7∶1,温度40℃,溶剂量75 mL,产物的最高产率可达到95.8%。     

金属钠—硫磺法合成聚苯硫醚

以金属钠和硫磺为原料,六磷胺作溶剂合成了聚苯硫醚。本工作表明,反应分为两个阶段,首先硫八元环断裂生成了由硫化钠和六磷胺组成的中间产物,中间产物再与对二氯苯反应生成聚苯硫醚。本工作还对钠与溶剂的反应及反应中微量水的影响作了研究。     

电感耦合等离子体原子发射光谱(ICP-AES)法测定气井产出液中金属元素

气井产出液中金属元素组成和含量的测定,对于集输系统缓蚀剂的配伍性研究和应用,以及判定下游天然气净化厂脱硫装置发泡、堵塞、腐蚀产生的原因均具有指导意义,因此建立了电感耦合等离子体原子发射光谱(ICP-AES)法测定气井产出液中钾、钠、钙、镁、铁、钡元素的含量。实验确定了最佳分析谱线、样品前处理步骤和酸度等分析条件。利用膜过滤、有机溶剂萃取分离油脂和酸处理3个步骤对工业样品进行前处理,实现了6种元素同时检测。各元素在1~100μg/mL内呈良好线性关系,检出限不高于0.08μg/L,加标回收率达到97.1%~105%,重现性相对标准偏差(RSD)<3.5%;和国家标准溶液比对,方法的相对误差<4%。方法重现性和准确度均满足分析要求。方法成功地检测了气田水、酸化返排液中钾、钠、钙、镁、铁、钡组分含量,具有良好的可靠性和实用性。     

阴离子交换色谱-脉冲安培法检测味精中的硫化物

建立了阴离子交换色谱柱分离、脉冲安培检测器测定味精中微量硫化物的方法。味精样品经2 g/L氢氧化钠溶液直接溶解并过滤后直接进样,硫离子与高浓度谷氨酸等阴离子在IonPac AS7阴离子色谱柱(250 mm×4 mm)上可实现较好的分离。以100 mmol/L氢氧化钠-500 mmol/L醋酸钠-0.5%乙二胺为淋洗液等度淋洗,6 min内可完成一次样品测定。脉冲安培检测器检测硫离子的检出限(25 μL进样,信噪比为3)为0.3 μg/L,并具有较宽的线性范围(0.001～1 mg/L),样品加标回收率为94.2%～99.0%。应用该方法检测99%味精、增鲜味精和加盐味精样品中的硫化物,结果表明该方法具有简便快捷、高选择性、高灵敏度等优点。     

Sodium Hydrogen Sulfate in Poly(ethylene glycol). An Efficient Recyclable System for the Deprotection of 1,1-Diacetates

Summary. Poly(ethylene glycol) was used as the solvent for selective deprotection of 1,1-diacetates (acylals) with easy recyclability of solvent and sodium hydrogen sulfate catalyst. This method is high yielding, fast, clean, safe, and therefore very suitable for practical organic synthesis.     

Multiresidue analysis of 18 organochlorine pesticides in traditional chinese medicine

A simple and efficient method for simultaneous gas chromatographic (GC) determination of 18 organochlorine pesticides [tecnazene, hexachlorobenzene, alpha-benzenehexachloride (BHC), pentachloronitrobenzene (PCNB), gamma-BHC, heptachlor, aldrin, methyl pentachlorophenyl sulfide, beta-BHC, delta-BHC, heptachlor epoxide, alpha-endosulfan, trans-chlorodane, cis-chlorodane, p,p'-dichlorodiphenyl dichloroethylene, o,p'-DDT, p,p'-DDD, and p,p'-DDT] in Traditional Chinese Medicine (TCM) is described. The procedure involves ultrasonic extraction and sulphuric acid treatment as the cleanup method. Detection of the sample is performed by GC-electron capture detection. A series of experiments are conducted to optimize the final pretreatment conditions [acetone-petroleum ether (1:1) as the extract solvent, ultrasonication for 15 min, three steps, concentrated sulphuric acid with 10% water for sulphuric acid treatment]. Recovery studies are performed at 10, 50, and 100 parts-per-billion (ppb) fortification levels of each organochlorine pesticide, except for alpha-endosulfan, which are 20, 100, and 200 ppb. The percentage recoveries range from 77.9% +/- 6.4% to 114.0% +/- 8.1% (average +/- standard deviation). The simple and rapid method may be used to routinely determine organochlorine pesticides in TCM.     

Derivatization-Gas Chromatographic Determination Of Mercaptans

Abstract

After being precipitated as silver mercaptides, mercaptans were converted into their pentafluorobenzyl derivatives in high yields by reaction with sodium sulfide and then with pentafluorobenzyl bromide. The derivatives were analyzed down to sub-ppm levels by gas chromatography with a flame ionization detector. It is possible that the above method is developed for the trace analysis of mercaptans in environmental matrices.     

1H NMR for quantifying sulfide trapping efficiency by using 1,3,5‐tris(2‐hydroxyethyl)‐1,3,5‐triazinane

Hydrogen sulfide (H₂S) is an extremely toxic colourless gas; it is corrosive and denser than air. It usually happens in oil and natural gas fields, refineries, coal mines, and in some industrial effluent treatment systems. This work presents an alternative method of monitoring and quantifying H₂S trapping efficiency by using 1,3,5‐tris(2‐hydroxyethyl)‐1,3,5‐triazinane as a sequestering agent, and sodium sulfide as a source of sulfide ion, through ¹H NMR spectroscopy. The results proved that the reaction occurs very quickly at 20 °C at pH 7 and 10. 3,5‐di(2‐hydroxyethyl)‐1,3,5‐thiodiazinane and 5‐(2‐hydroxyethyl)‐1,3,5‐dithiozinane were observed and quantified; it was evidenced that ¹H NMR spectroscopy can be applied as a fast and effective method to quantify H₂S trapping efficiency. Copyright © 2014 John Wiley & Sons, Ltd.     

S-oxidation of thiazolidinedione with hydrogen peroxide, peroxynitrous acid, and C4a-hydroperoxyflavin: a theoretical study

Quantum chemical analysis was carried out to model metabolism of glitazone class of drugs through oxygen transfer process to the sulfur atom of thiazolidinedione ring with different oxidants such as H(2)O(2), HOONO, and C4a-hydroperoxyflavin. Complete optimization (geometric and energy parameters) of all the required structures and transition states on the reaction path was carried out using MP2(full)/6-31+G(d,p). Charge and second-order delocalization analyses of important structures were carried out using the NBO method. The effect of solvent on the oxygen transfer to sulfur of thiazolidinedione was studied by including one, two, or three explicit water molecules. These calculations revealed that explicit solvent (water) effectively contributed in the sulfoxidation of thiazolidinedione and led to remarkable reduction in the energy barrier by ～10 kcal/mol as compared to the gas phase. These results were found to be consistent with previously reported S-oxidation of dimethyl sulfide. When explicit water molecules were included, solvent molecules stabilize the charge separation at the transition state via specific interactions, and oxidation occurs via stretching of the O-O bond of oxidants and gradual formation of S-O bond. This study is helpful in understanding the metabolite generation due to the S-oxidation process in the glitazone series of antidiabetic drugs under physiological conditions.     

聚间苯硫醚和聚对苯硫醚的对比表征

聚对苯硫醚[poly(pphenylenesulfide),简称pPPS]的分子链是由对苯撑基和硫原子交替连接构成而使制品抗冲击能力差[1](有些研究者用共聚或共混的方法在pPPS中引入间位结构来达到减少其结晶度,增强韧性的目的)。余自力等[2]用硫磺溶液法合成了mPPS、pPPS及其共聚物,认为在pP...     

o-Quinone methide as alkylating agent of nitrogen, oxygen, and sulfur nucleophiles. The role of H-bonding and solvent effects on the reactivity through a DFT computational study

The reactivity of the alkylating agent o-quinone methide (o-QM) toward NH(3), H(2)O, and H(2)S, prototypes of nitrogen-, oxygen-, and sulfur-centered nucleophiles, has been studied by quantum chemical methods in the frame of DF theory (B3LYP) in reactions modeling its reactivity in water with biological nucleophiles. The computational analysis explores the reaction of NH(3), H(2)O, and H(2)S with o-QM, both free and H-bonded to a discrete water molecule, with the aim to rationalize the specific and general effect of the solvent on o-QM reactivity. Optimizations of stationary points were done at the B3LYP level using several basis sets [6-31G(d), 6-311+G(d,p), adding d and f functions to the S atom, 6-311+G(d,p),S(2df), and AUG-cc-pVTZ]. The activation energies calculated for the addition reactions were found to be reduced by the assistance of a water molecule, which makes easier the proton-transfer process in these alkylation reactions by at least 12.9, 10.5, and 6.0 kcal mol(-1) [at the B3LYP/AUG-cc-pVTZ//B3LYP/6-311+G(d,p) level], for ammonia, water, and hydrogen sulfide, respectively. A proper comparison of an uncatalyzed with a water-catalyzed reaction mechanism has been made on the basis of activation Gibbs free energies. In gas-phase alkylation of ammonia and water by o-QM, reactions assisted by an additional water molecule H-bonded to o-QM (water-catalyzed mechanism) are favored over their uncatalyzed counterparts by 5.6 and 4.0 kcal mol(-1) [at the B3LYP/6-311+G(d,p) level], respectively. In contrast, the hydrogen sulfide alkylation reaction in the gas phase shows a slight preference for a direct alkylation without water assistance, even though the free energy difference (DeltaDeltaG(#)) between the two reaction mechanisms is very small (by 1.0 kcal mol(-1) at the B3LYP/6-311+G(d,p),S(2df) level of theory). The bulk solvent effect, evaluated by the C-PCM model, significantly modifies the relative importance of the uncatalyzed and water-assisted alkylation mechanism by o-QM in comparison to the case in the gas phase. Unexpectedly, the uncatalyzed mechanism becomes highly favored over the catalyzed one in the alkylation reaction of ammonia (by 7.0 kcal mol(-1)) and hydrogen sulfide (by 4.0 kcal mol(-1)). In contrast, activation induced by water complexation still plays an important role in the o-QM hydration reaction in water as solvent.     

Synthesis of polyphenylene ether and thioether ketones

The known polymerization of 4,4′-difluorobenzophenone (DFB) with the dianion of hydroquinone to poly(phenylene ether ether ketone) (PEEK) and polymerization of either DFB with the dianion of 4,4′-dihydroxybenzophenone or self polycondensation of the anion of 4-hydroxy-4′-fluoro-benzophenone to poly(phenylene ether ketone) (PEK) were studied in N-cyclohexyl-2-pyrrolidone (CHP), which is a high-boiling aprotic polar solvent. The formation of high-molecular weight PEEK and PEK in this solvent was very efficient. The reactivity in CHP can be ascribed to effective solvation of metal ions rendering the anion very reactive toward nucleophilic substitution. The polymerization was extended to 4,4′-bis(4-fluorobenzoyl)diphenyl ether and 1,4-bis[4-(4-fluorobenzoyl)phenoxy]benzene to give a high molecular weight polymer with PEK and PEEK repeating units and PEEK respectively. The polymerization of DFB with purified anhydrous sodium sulfide in CHP gave rapidly a high molecular weight poly(phenylene ketone sulfide) (PKS). In contrast, diphenyl sulfone (DPS) was not very effective in obtaining such a high molecular weight PKS even with prolonged heating, which suggests the uniqueness of CHP in promoting a high degree of polymerization.     

Development of a simultaneous liquid-liquid extraction and chiral derivatization method for stereospecific GC-MS analysis of amphetamine-type stimulants in human urine using fractional factorial design

A stereospecific gas chromatography-mass spectrometry analysis method for amphetamine-type stimulants in human urine was recently developed. For maximum efficiency, liquid-liquid extraction and chiral derivatization of the analytes using (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride were performed simultaneously. The effects of (1) use of saturated sodium chloride in 2.0 m sodium hydroxide, (2) extraction solvent volume, (3) percentage of triethylamine, (4) derivatization reagent volume, (5) sample mixing time, (6) incubation temperature and (7) incubation time on method sensitivity and variability were assessed using a two-level, eight-run Plackett-Burman design followed by a fold-over design. The use of saturated sodium chloride solution and the derivatization reagent volume were significant factors (ANOVA, p < 0.01). The saturated sodium chloride solution decreased sensitivity whereas an increased volume of derivatization reagent increased sensitivity. Calibration curves for all analytes were linear between 5 and 500 microg/L, with correlation coefficients of >0.99. Detection limits were 相似文献   

The Synthesis of Sodium Sulfide Pentahydrate,Na2S·5H2O,Through a Solid-Gas Reaction of Sulfidizing Gas Mixture with Sodium Carbonate,Na2CO3

In this study, the sulfidization of Na₂CO₃ was investigated by using a solid-gas reaction under a sulfidizing gas mixture, which consisted of COS, CS₂, and S₂ gases.

Sodium sulfide pentahydrate, Na₂S·5H₂O, was prepared from sodium carbonate, Na₂CO₃, via a sulfidizing gas mixture by a solid-gas reaction under the cooling of a nitrogen atmosphere. The observed phase was found to be the pentahydrated form of sodium sulfide. This crystalline form was determined by X-ray powder diffraction (XRD) technique. Since sodium sulfide is strongly hygroscopic, the pentahydrated crystalline form was observed in XRD measurements for all repeated experiments. The crystal unit cell parameters of the synthesized product were in excellent agreement with values given in the JCPDS card number 18-1249. The sodium sulfide pentahydrate has an orthorhombic crystal structure with the unit cell parameters of a = 6.475, b = 12.55, C = 8.655 Å, space group, Cmcm and Z = 4.