Direct polyesterification promoted by a complex of phosphorus oxychloride with LiCl monohydrate

The reaction of benzoic acid and p-chlorophenol with phosphorus oxychloride (POC) was significantly affected by the presence of metal salt hydrates or a mixture of metal salts and water sufficiently aged. Among metal salts examined, LiCl was most effective for the reaction to give quantitative yield of the benzoate. The reaction was assumed to proceed via a complexation of POC with LiCl monohydrate followed by selective hydrolysis of POC by water bound to LiCl. The reaction promoted by a complex derived from POC and LiCl monohydrate in pyridine was successfully used as a new condensing agent for the synthesis of aromatic polyesters by the direct polycondensation or aromatic dicarboxylic acids and bisphenols. Under favorable conditions for aging of POC with LiCl monohydrate and for addition of bisphenols, polymers of moderate to high molecular weights were obtained in quantitative yield. The reaction was applied with limited success to the preparation of a copolymer of high molecular weight from hydroxybenzoic acids.     

Investigation of polycondensation through the copolycondensation of preformed oligomers and bisphenols by a two‐stage solution reaction with tosyl chloride,dimethylformamide, and pyridine

A two‐stage copolycondensation of an equimolar mixture of isophthalic acid and terephthalic acid first with a bisphenol (BP) and then with another BP was carried out with a tosyl chloride/dimethylformamide/pyridine condensing agent. When the preformed oligomers from a BP with no substituent or a methyl substituent were allowed to react with another BP comonomer containing polar SO₂, CO, or Cl groups, the copolycondensation was significantly promoted. Such effects were absent with the unsubstituted BP and the methyl derivative. In addition, during the reaction of oligomers from BPs with polar groups, a similarly polar BP did not react so effectively, and the unsubstituted BP did not have any effect on the copolycondensation. On the basis of the sequence distributions for the resultant copolymers determined by ¹H NMR, it was likely that the copolycondensation could be promoted when the second comonomers were randomly distributed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4024–4031, 2002     

Synthesis of polyesters as binders for deinkable inks. I. Structural analysis of the polyesterification between o-phthalic anhydride and neopentyl glycol in bulk at 200°C by high resolution 13C nuclear magnetic resonance (13C-NMR)

Analysis of the polyesterification in bulk without any external catalyst at 200°C of o-phthalic anhydride with neopentyl glycol (2,2-dimethyl-1,3-propanediol) with a mole ratio ([(SINGLE BOND) COOH]/[ (SINGLE BOND) OH]) = 0.7 has been carried out by high resolution ¹³C nuclear magnetic resonance (¹³C-NMR). Polyesters can be analyzed by ¹³C-NMR spectra because of the fact that both o-phthalic acid (o-phthalic anhydride) and neopentyl glycol carbons are sensitive to sequence effects. Spin-lattice relaxation times T₁, of quaternary, tertiary and secondary carbons in different structures are in the 0.1–6.5 s range depending on the neighboring residue effects in the polymer chain. © 1996 John Wiley & Sons, Inc.     

Copolycondensations of bisphenols with aggregates of isophthalic acid and terephthalic acid activated by tosyl chloride/dimethylformamide/pyridine in different manners

A mixture of isophthalic acid (IPA) and terephthalic acid (TPA) was activated by a tosyl chloride/dimethylformamide/pyridine (Py) condensing agent in two steps via the treatment of a mixture of the initially activated IPA/TPA with additional TPA followed by the activation of TPA with the agent. The resulting mixture showed a solubility in Py different from that obtained by the activation of them all at once; the difference might be due to different structures of the aggregates of the activated IPA and TPA at the same composition of the diacids. The structures of the aggregates were evaluated on the basis of melting points and the IR spectra of a mixture of dimethyl esters of IPA and TPA produced by the quenching of the reaction mixtures with methanol. The mixture obtained by two‐step activation showed lower melting points and spectral changes due to enhanced associations of the esters with respect to the mixture prepared by the activation of them all at once. The aggregates were also examined in terms of the distributions of IPA and TPA in thermotropic copolyesters prepared from methylhydroquinone and chlorohydroquinone by their transition temperatures and ¹³C NMR. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3884–3892, 2001     

Random copolycondensation of isophthalic acid/terephthalic acid with bisphenols by tosyl chloride/dimethylformamide/pyridine in terms of the monomer reactivity ratios of bisphenols

The random copolycondensation of isophthalic acid/terephthalic acid with various combinations of bisphenols (M₁ and M₂) with a tosyl chloride/dimethylformamide/pyridine condensing agent was carried out to investigate the effects of the monomer reactivity ratios, r₁′ and r₂′, on the reaction, like r₁ and r₂ in radical copolymerization. The ratios were calculated from the probabilities of finding an M₂ unit next to an M₁ unit and of finding an M₁ unit next to an M₂ unit, which were determined by an NMR analysis of the resultant copolymers. They were discussed with respect to the inherent viscosities (molecular weights) of the resultant copolymers. There was a fairly good relationship between r₁′ and r₂′ and the inherent viscosity values of the copolymers, indicating that copolycondensation could be facilitated by a combination of bisphenols; the lowering of r₁′ and r₂′ was indicative of random distributions in the copolymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3908–3915, 2003     

Preparation of the thermotropic copoly(amide ester) of p‐aminobenzoic acid and m‐hydroxybenzoic acid with diphenyl chlorophosphate/pyridine

A thermotropic copoly(amide ester) exhibiting a nematic mesophase within the range of 240–360 °C was prepared by the solution copolycondensation of p‐aminobenzoic acid (40–70 mol %) and m‐hydroxybenzoic acid with diphenyl chlorophosphate in pyridine in the presence of LiCl. For control of the sequence distribution of p‐aminobenzoic acid, the amount of LiCl and the dropwise addition of the phosphate were examined. The transition temperatures (from a solid phase to a nematic mesophase) of the resultant copolymers were affected by the period of addition and the amounts of the aminobenzoic acid and LiCl and were investigated in terms of the distributions of the monomers determined by ¹H NMR. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1775–1780, 2002     

Regioselective dehydration of axial and equatorial tertiary alcohols with α-methyl group in the cyclohexane ring by Swern’s reagent

Swern’s reagent (a complex of oxalyl chloride with DMSO) was shown to dehydrate tertiary alcohols containing an α-methyl group in the cyclohexane ring. Dehydration of equatorial alcohols affords mixtures of isomeric compounds where isomers with an exocyclic double bond dominate, whereas isomers with an endocyclic double bond prevail in the products of dehydration of axial tertiary alcohols. Thus, Swern’s reagent can serve as a chemical test to determine the configuration of tertiary alcohols containing an α-methyl group in cyclohexane ring. The composition of the products of dehydration of these alcohols with Swern’s reagent is similar to that obtained by their dehydration with POCl₃ in pyridine. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 800–803, April, 1997.     

连续流动法同时测定污水中氨氮和总磷

采用连续流动分析法测定污水中氨氮、总磷的含量。比较了污水样品不同的稀释倍数对测定结果的影响。实验结果表明:氨氮和总磷的质量浓度在0.1~8 mg/L范围内线性良好,线性相关系数均为0.99997;测量结果的相对标准偏差分别为2.01%,0.84%(n=7);方法检出限分别为0.012,0.009 mg/L;质控样测量值均在标示值范围内;样品加标回收率为93.4%~101.1%。污水的洁净程度对测定结果影响较大。洁净度高的污水,直接测定与稀释后测定,测定值无显著性差异;而洁净度低的污水,直接测定与稀释后测定结果差异比较大。该法采用全谱直读CCD检测方式,灵敏度高,稳定性好,无光谱干扰,且支持氨氮和总磷同时测定,方便快捷,适合污水中氨氮和总磷的测定。     

离子色谱法测定海产品中磷酸盐、焦磷酸盐、偏磷酸盐和总磷

建立了离子色谱法测定海产品中磷酸盐、焦磷酸盐、偏磷酸盐和总磷的分析方法。样品经100 mmol/L NaOH溶液浸提,固相萃取柱去除有机物、阳离子、中和OH~后用于海产品中磷酸盐、焦磷酸盐和偏磷酸盐的测定;样品经干灰化法消化,固相萃取柱净化后用于总磷测定。考察了提取溶液的pH、有机物和共存离子对测定结果的影响。该方法的线性范围为0.3～60 mg/L,检出限为2.1～2.3 mg/kg,相对标准偏差为1.6%～2.6%。海鱼和虾仁样品中目标物的加标回收率为81.8%～100.0%。该方法选择性好,灵敏度高,用于实际样品测定结果令人满意。     

Determination of available phosphorus in soils by using a new extraction procedure and a flow injection amperometric system

A new extraction procedure based on an off-line extraction column was proposed for extracting of available phosphorus from soils. The column was fabricated from a plastic syringe fitted at the bottom with a cotton wool and a piece of filter paper to support a soil sample. An aliquot (50 mL) of extracting solution (0.05 M HCl + 0.0125 M H₂SO₄) was used to extract the sample under gravity flow and the eluate was collected in a polyethylene bottle. The extract was then analyzed for phosphorus contents by a simple flow injection amperometric system, employing a set of three-way solenoid valves as an injection valve. The method is based on the electrochemical reduction of 12-molybdophosphate which is produced on-line by the reaction of orthophosphate with acidic molybdate and the electrical current produced was directly proportional to the concentration of phosphate in range of 0.1-10.0 mg L⁻¹ PO₄-P, with a detection limit of 0.02 mg L⁻¹. Relative standard for 11 replicate injections of 5 mg L⁻¹ PO₄-P was 0.5%. A sample through put of 35 h⁻¹ was achieved, with consumption of 14 mg KCl, 10 mg ammonium molybdate and 0.05 mL H₂SO₄ per analysis. The detection system does not suffer from the interferences that are encountered in the photometric method such as colored substances, colloids, metal ions, silicate and refractive index effect (Schlieren effect). The results obtained by the column extraction procedure were well correlated with those obtained by the steady-state extraction procedure, but showed slightly higher extraction efficiency.     

Fluorinated pyridine derivatives: Part 1. The synthesis of some mono- and bis-quaternary pyridine salts of potential use in the treatment of nerve agent poisoning

Experiments were performed to determine whether F- and CF₃-substituted pyridines undergo quaternization with iodomethane (1:1 molar ratio in THF) and 1,3-diiodopropane (2:1 molar ratio in MeCN). 2-Fluoropyridine and 2-(trifluoromethyl)pyridine did not react with MeI even under prolonged reflux, while 3-fluoropyridine, 3,5-difluoropyridine, 3-(trifluoromethyl)pyridine and 4-(trifluoromethyl)pyridine gave methiodide salts in 28-72% yield. 2-Fluoropyridine did not react with I(CH₂)₃I, 3-fluoropyridine gave the bis-quaternary salt and 3,5-difluoropyridine yielded a mono-quaternary derivative. Both 3- and 4-(trifluoromethyl)pyridine furnished the bis-quaternary products in 53 and 55% yield, respectively. The bis-quaternary salts are potentially useful in the treatment of organophosphorus nerve agent poisoning.     

Additional evidence of possible structural effect of diol units in preformed oligoesters on solution copolycondensation with x,y‐dihydroxytoluenes and their isomers promoted by tosyl chloride/dimethylformamide/pyridine

A two‐stage copolycondensation of a mixture of equal parts of isophthalic acid and terephthalic acid was conducted using a tosyl chloride/dimethylformamide/pyridine condensing agent. In the initial stage x,y‐dihydroxytoluenes (x,y‐DHTs) or 2,4‐dihydroxyethylbenzene (2,4‐DHEB) was used and in the next stage isomeric DHTs or the DHEB was used. The results were examined in terms of how the reaction of the resulting oligomers with the next monomers proceeded, which was evaluated from distributions of the next monomers in the resultant copolymers as determined by ¹H NMR. A structurally selective reaction was observed. The preformed oligomers from symmetrically substituted 3,5‐DHT reacted randomly with similarly substituted 2,6‐DHT or asymmetric 2,4‐DHEB, but those from 2,4‐DHEB reacted selectively with both of 3,5‐ and 2,6‐DHT. In the reactions of the oligomers from 2,6‐DHT, they reacted randomly with 2,6‐DHT but selectively with 2,4‐DHEB. Such selective reactions were also observed in the reaction of p‐isomeric 2,5‐DHT with the oligomers prepared from 3,5‐ or 2,6‐DHT. When the monomers were copolymerized simultaneously instead of stepwise, they distributed randomly in the resultant copolymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5687–5694, 2004     

电感耦合等离子体质谱(ICP-MS)法测定高纯砷中痕量磷和硒

通过对样品前处理方式、内标元素及质量数的选择、仪器检测模式等方面进行优化,采用串联四级杆电感耦合等离子体质谱仪直接测定高纯砷中痕量的磷和硒.实验室使用电子级盐酸、硝酸配制王水直接溶解样品,在不除基体的情况下,以铑作为内标补偿校正砷基体的抑制效应,在调试好的仪器上进行测定磷、硒含量.磷、硒的测定结果相对标准偏差(RSD)...     

Control of chain ends of polyesters in polycondensation of AA and BB monomers by use of solid‐phase reagent

For selective synthesis of linear polyester having a functional group at one end, polycondensation between 1,4‐butanediol ( 1a ) and sebacoyl chloride ( 2a ) and between 1,12‐dodecanediol ( 1b ) and isophthaloyl chloride ( 2b ) was conducted in the presence of oxime resin or oxime silica gel, followed by cleavage of the formed polyester from the solid‐phase support with aniline. Matrix‐assisted laser desorption ionization time‐of‐flight mass spectra and ¹H NMR spectra of the cleaved polyester showed that the products contained not only polyester with anilide at one end ( poly 1 ), but also polyester with anilides at both ends ( poly 2 ). The product ratio of poly 1 to poly 2 ( poly 1 / poly 2 ) was dependent on monomers, monomer concentration, feed ratio of monomer to oxime moiety in the support, oxime content in the support, reaction solvent, and the nature of the support. Polyester with a high poly 1 / poly 2 ratio of 81/21 and moderate molecular weight (M_n = 1430 g/mol) was obtained by polycondensation of 1b and 2b in the presence of oxime silica gel in dichloromethane. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1379–1386     

电感耦合等离子体发射光谱法检测镍基/钴基高温合金中硼磷硅

采用一定比例的混合酸溶解样品,利用基体匹配配制一系列标液消除基体的影响,以及轴向观测喷嘴吹扫技术来提高待测元素的灵敏度,使用电感耦合等离子体发射光谱(ICP-OES)测定镍基/钴基高温合金中硼磷硅。各元素选的分析线依次为B 182.577 nm、P 178.222 nm、Si 185.005 nm。检测范围分别是：B：0.001%-3.0%,P：0.003%-0.20%,Si：0.005%-3.0%,检出限范围是0.00005%-0.0004%,线性相关系数>0.9995。加标回收率为90.0%-105.0%,精密度RSD<2.0%。该方法操作简单快速,结果令人满意。     

碳源对SBR单级好氧工艺中微生物摄磷能力的影响及其机理研究

以两种典型基质：葡萄糖（R1）和乙酸钠（R2）作为单一碳源,考察了SBR单级好氧工艺在R1和R2中的除磷效果,并通过比较各自微生物体内储能物质的变化,探讨了SBR单级好氧工艺以不同基质作为碳源时影响其微生物摄磷能力的根本原因．结果表明：R1和R2中均观察到明显的超量摄磷现象,但在运行条件完全相同的情况下,两系统中微生物摄磷能力以及体内储能物质有很大的差别．稳定运行后,R1和R2中单位混合液挥发性悬浮固体（MLVSS）的总磷（TP）去除量分别为6．7～7．4、2．7～3．2mg·g^-1．R1中微生物体内储能物质多β羟基烷酸盐（PHA）含量没有明显的变化,另一储能物质糖原质在好氧段外碳源（葡萄糖）存在时有明显的积累现象（糖原质的最大积累量为3．21mmol-C·g^-1）,在好氧段外碳源消耗完后呈下降趋势,并在好氧结束时下降到好氧前水平;R2中PHA与糖原质在好氧段外碳源（乙酸钠）存在时均有明显的积累现象（外碳源消耗完时PHA与糖原质积累量分别为2．1,0．55mmol—C·g^-1）,PHA在好氧段外碳源消耗完后呈下降趋势,并在好氧结束时也几平下降到好氧前水平,而糖原质却在外碳源消耗完后继续积累,并在好氧2h左右时达到最大值（糖原质最大积累量为0．88mmol—C·g^-1）,此后下降明显,在好氧结束时也几乎恢复到原始水平．在整个好氧过程中,R1中内碳源（PHA与糖原质）的积累／转化量大于R2系统．在闲置期内,R1与R2中PHA与糖原质均没有明显变化,但却观察到明显的释磷现象,且R1释磷量多于R2系统．此研究显示,由于R1与R2中进水碳源不同,在其反应系统内碳源的好氧代谢途径有所差别,使各自微生物在好氧段体内储能物质的类型与积累／转化量也有所不同,各自微生物在好氧摄磷时得到的可利用的能量也不同,因而各自微生物的摄磷能力亦有所差别．     

Structural organization of phosphorus titanate oxides prepared by the alkoxo method and their catalytic activity in ethylene glycol oxyethylation

The relationship of the structural organization and acid-base properties of the surface of phosphorus titanate oxides prepared from tetra-n-butoxytitanium and phosphorous esters with the catalytic activity and selectivity of these materials in ethylene glycol oxyethylation was studied. Single-phase phosphorus-containing oxides synthesized from 2-diethylamido-4-methyl-1,3,2-dioxophosphorinane and diphenyl(methano)phosphocane have strong surface aprotic acid sites and exhibit high catalytic activity with respect to oxyethylation and a record-breaking selectivity in the formation of the lower homolog, diethylene glycol. The last-mentioned fact is a consequence of the sieve effect exerted by the homogeneous porous structure of supermicropores (8—10 ) of the oxides. An increase in the concentration of the strong acid sites (130 kJ mol^–1) on the oxide surface enhances the catalytic activity. On the basis of the temperature programmed desorption of ammonia and CO₂ and kinetic measurements, a concerted acid-base mechanism was proposed for the catalytic addition of ethylene oxide to ethylene glycol on the phosphorus-titanate surface.     

The use of 2-2-thiazolylazo-p-cresol to minimize the interference of Ni and Cu for the bismuth determination in alloys by hydride generation atomic absorption spectrometry

Thiazolylazo p-cresol (TAC) was studied as a masking agent for the determination of Bi in rich Ni and Cu alloys by hydride generation atomic absorption spectrometry (HGAAS). In the presence of TAC, Bi/Ni and Bi/Cu ratios up to 1:160 000 and 1:16 000, respectively, were found to be tolerable. No buffering was necessary once the masking agent was effective even in very acid medium. Limits of detection at the low mug g(-1) range were reached and the accuracy of the procedure was confirmed by the good concordance between found and certified values in the analysis of certified reference materials (CRM).