对溴苯甲醛的间接电化学合成

以硫酸为介质,利用电解MnSO4生成Mn3+将对溴甲苯氧化为对溴苯甲醛;通过设计有机氧化正交实验L9(33),对电解氧化条件进行了优化.优化电解条件为:硫酸浓度6.5 mol/L、对溴甲苯与Mn3+摩尔比1∶4、电解时间6 h、合成时间3 h、温度65℃;相应的电流效率可达75.36%,对溴苯甲醛的产率可达75.47%.所采用的间接电化学合成工艺路线简单,使用后的媒质可以再生循环使用,符合绿色生产的要求.     

O-羧甲基黄原酸壳聚糖合成及应用研究

以壳聚糖(CS)为原料,先制备出O-羧甲基壳聚糖(OCMC),再和二硫化碳在碱性条件下合成O-羧甲基黄原酸壳聚糖(CXCS)。通过产物的含硫量对碱浓度、投料比和反应时间等因素进行了优化,采用固体13CNMR和SEM表征其结构。结果表明,合成CXCS的最佳条件为碱浓度10%,投料比1∶1,室温反应3h,产品的含硫量达10.22%。最后研究了CXCS对水溶液镉离子的吸附性能,结果表明CXCS具有优异的吸附性能,其最大吸附量可达288.5 mg/g,是壳聚糖吸附量的2.65倍。红外分析结果表明吸附主要依靠结构中的羧基和黄原酸基团。     

介孔分子筛Al-MCM-41制备及催化合成二芳基乙烷

以硅酸钠为硅源、硫酸铝为铝源、CTAB为模板剂,采用水热法合成了骨架负载型固体酸Al-MCM-41介孔分子筛催化剂,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)和红外(IR)方法对其进行了表征,同时研究了该催化剂在二芳基乙烷合成反应中的催化性能. 考察了各种反应因素的影响,确定其最佳合成条件为:原料m(苯乙烯)∶m(二甲苯)=1∶7.5,催化剂用量为1%(总投料质量分数),反应时间为3 h,反应温度为140 ℃,产率可达87.1%,比传统催化剂浓硫酸提高了17%. 研究结果表明,该催化剂是替代液体酸合成二芳基乙烷的理想固体酸催化剂.     

固体酸SO42-/SiO2-TiO2催化合成乙酰水杨酸研究

以水杨酸和乙酸酐为原料,用SO■/SiO_2-TiO_2固体酸为催化合成乙酰水杨酸,考察了TiO_2与SiO_2质量比、硫酸浸渍量、浸渍时间、煅烧温度等因素对乙酰水杨酸产率影响,通过红外光谱、扫描电镜和激光粒度仪对催化剂或合成产物进行了表征。得到最佳反应条件:SiO_2:TiO_2质量比为0.4:1、硫酸浸渍量与TiO_2质量比为0.49:1、浸渍时间为26 h、煅烧温度为400℃,该条件下制备的固体酸催化合成乙酰水杨酸产率为65%。该催化剂具有易与反应体系分离,对设备腐蚀性小,可再生等优点。     

氨基化四氧化三铁磁性纳米粒子富集石墨炉原子吸收法检测苯胂酸

合成了磁性功能材料,氨基化的Fe3O4纳米粒子,以丙酮作溶剂对洛克沙胂、对氨基苯胂酸、对羟基苯胂酸、对硝基苯胂酸、对酰胺基苯胂酸进行吸附,石墨炉原子吸收光谱法进行检测。对合成的磁性材料进行了表征,并详细研究了其对苯胂酸的吸附性能。结果表明,合成的磁性材料对苯胂酸具有良好的选择性,5 min内便可吸附完全,吸附率接近100%。该方法在10～200 ng/mL范围内线性良好,检出限低于1 ng/mL,RSD均低于5.6%,将合成材料用于鸡饲料中5种苯胂酸的测定,加标回收率均在63%～104%之间。     

固相微萃取-GC-MS法测定水中的三苯胂和二苯胂酸

建立了一种同时测定水中痕量三苯胂和二苯胂酸的方法,使用巯基乙酸甲酯作为二苯胂酸测定的衍生化试剂,固相微萃取耦合气相色谱-质谱法(选择离子监测)同时测定三苯胂和二苯胂酸。优化了萃取纤维丝、萃取时间、衍生化等操作条件。同时对混合物测定的回收率、相对标准偏差和最低检测限进行了研究。方法的回收率大于95%,最低检测质量浓度分别为0.0005和0.0003 mg/L,6次测定的相对标准偏差分别为5.3%、7.6%。     

直接硝化法合成邻硝基对甲酚

考察了用对甲酚和硝酸在二氯甲烷中合成邻硝基对甲酚的工艺条件,对影响反应的因素,如分散度、反应时间、反应温度、硝酸浓度等进行了优选,产率达到了82.3%.     

煤酸异构化制对苯二甲酸

进行了煤氧化产物煤酸（水溶酸WSA）钾在催化剂碳酸镉的存在下，异构化制对苯二甲酸(TPA)的研究。主要考察了催化剂用量、二氧化碳初压、反应温度和反应时间对TPA产率的影响。结果表明，在催化剂存在下煤酸可以转化成TPA。单独煤酸钾异构化时，较佳反应条件：温度430 ℃～450 ℃，压力4.0 MPa，催化剂CdCO3用量4%，反应时间2 h。煤酸钾与苯甲酸（BA）钾混合异构化时，较佳反应条件与单独煤酸钾时基本相同。单独煤酸钾在较佳条件下异构化时，粗TPA产率达34%左右，相当于根据其中有效成分苯多羧酸（BPCA）计算的理论产率的75%左右，选择性较好。煤酸钾加苯甲酸钾在较佳条件下异构化时,粗TPA产率可达68%，扣除假定BA自身岐化生成TPA理论产量之后，则煤酸的TPA产率高达70%，比煤酸单独异构化TPA产率(34%)高1倍。粗TPA经精制可得纯度99%以上的精TPA。     

2—硝基—4—甲基苯胂酸粉晶X射线衍射数据的指标化研究

2-硝基-4-甲基苯胂酸分子中的胂酸基能与稀土元素络合显色,是合成重要显色剂的反应中间体。了解它的结构,对设计合成路线、研究反应机理以及探索稀土元素的分析方法有着十分重要的意义。本文报道2-硝基-4-甲基-苯胂酸多晶样品X射线衍射数据,利用改进的尝试法将所有衍射数据指标化。该方法亦适用于六方、四方、正交、单斜和三斜物质粉末衍射数据的指标化。     

固体酸催化合成马来酸二丁酯

制备了固体酸催化剂Zr(SO4)2/SiO2,并用于合成马来酸二丁酯,考察了Zr(SO4)2负载量、焙烧温度、焙烧时间等催化剂制备条件对催化活性的影响。采用FTIR、XRD、TG等方法对催化剂进行了表征分析。通过正交实验设计优化了固体酸Zr(SO4)2/SiO2催化合成马来酸二丁酯的工艺条件。实验结果表明,Zr(SO4)2/SiO2是合成马来酸二丁酯的良好催化剂,适宜的催化剂制备条件为:硫酸锆负载量57%,焙烧温度400℃,焙烧时间2 h。适宜的催化合成反应条件为:酐醇物质的量比为1∶2.5,催化剂用量为马来酸酐质量的6%,带水剂甲苯8 mL,反应时间2.0 h。在此条件下马来酸二丁酯的酯化率为98.5%。     

Effect Factors in Synthesis of Nicotinic Acid by Electrooxidation of 3-Picoline

IntroductionNicotinic acid,whose IUPAC name is3-pyridineformic acid,also called Vitamin B3,is an importantraw material of chemical industry,an intermediate inthe synthesis processes of medicine,additives of food,drink and feed.It is also applied to anti-oxidants in ac-tive dyestuff and household chemicals,such as hair dyeand hair tonic agents,plastic stabilizer and photo-sen-sitive materials,etc.[1—3].There are a fewmethods forsynthesizing nicotinic acid at present.The oxidation of3-picoli…     

Supercritical fluid extraction and gas chromatography analysis of arsenic species from solid matrices

A method in combination with derivatization-supercritical fluid extraction(SFE) and gas chromatography(GC) for the speciation and quantitative determination of dimethylarsinate(DMA), monomethylarsonate(MMA) and inorganic arsenic in solid matrices was investigated. Thioglycolic acid methyl ester(TGM) and thioglycolic acid ethyl ester(TGE) were evaluated as derivatization reagents. The effects of pressure, temperature, flow rate of supercritical CO_2, extraction time, modifier and microemulsion on the efficiency of extraction were systematically investigated. The procedure was applied to the analysis of real soil and sediment samples. Results showed that TGE was more effective for arsenic speciation as a derivatization reagent. Modifying supercritical CO_2 with methanol can greatly improve the extraction efficiency. Further, the addition of microemulsion containing surfactant Triton X-100 can further enhance recoveries of arsenic species. The optimum extraction conditions were 100 ℃, 30 MPa, 10 min static and 25 min dynamic extraction with 5%(v/v) methanol, and surfactant modified supercritical CO_2. Detection limits in solid matrices were 0.15, 0.3 and 1.2 mg/kg for DMA, MMA and inorganic arsenic,respectively. The method was validated by the recovery data. The resulting method was fast, easy to perform and selective in the extraction and detection of various arsenic species in solid matrices.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定进口酸泥中砷和汞

本文采用硝酸和盐酸的混合酸低温溶解酸泥后,运用ICP-AES法同时测定进口酸泥中砷和汞。建立了最佳实验方法,确立各项分析条件,砷的测定范围：0.01%~10%,汞的测定范围：0.005%~10%。测定值相对标准偏差小于3%,加标回收率在97%~105%之间,该方法简单快速,准确度高,完全满足酸泥中砷和汞的测定要求。     

氢化物发生原子荧光法测定聚氯化铝中的砷含量

建立了氢化物发生原子荧光法测定聚氯化铝中砷含量的检测方法。将聚氯化铝样品用硫酸溶解,蒸至近干,用氢化物发生原子荧光法测定其中的砷含量。在最佳测定条件下,砷的质量浓度在0~10.0μg/L范围内与荧光强度呈良好的线性关系,相关系数r=0.999 3,砷的检出限为0.03μg/g,样品加标回收率为82.5%~90.0%,测定结果的相对标准偏差为1.5%~1.9%。该法具有快速、准确、灵敏度高等优点。     

酸性水稻土有效态砷与糙米砷含量相关性的研究

为了更好地探究酸性水稻土中有效态砷和糙米砷含量的相关性,采用土液比1:10、振荡时间240 min和振荡速度200 r·min-1为中间条件,比较4种浸提剂0.01 mol·L-1 CaCl2-DTPA,0.5 mol·L-1 NaHCO3,0.05 mol·L-1 NH4H2PO4和0.43 mol·L-1 HNO3提取酸性水稻土中有效砷的提取效果。结果表明,4种浸提剂提取的土壤有效态砷与其糙米砷含量之间均存在显著相关,0.43 mol·L-1 HNO3提取的土壤有效态砷与糙米砷含量的相关性最高为0.828,土壤有效态砷平均提取率最高为8.63。选择0.43 mol·L-1 HNO3为提取酸性水稻土有效态砷的最优浸提剂,进一步优化浸提剂的提取条件,确定土液比1:10、振荡时间120 min和振荡速度200 r·min-1为酸性水稻土有效态砷最佳提取条件,土壤有效态砷与糙米砷含量的相关性最高为0.831。0.43 mol·L-1 HNO3提取酸性水稻土中有效砷的方法操作简便、试剂用量少,提取的土壤有效砷和糙米砷的相关性好,确定为酸性水稻土有效态砷的提取方法,为科学评价酸性水稻土壤有效态砷与糙米砷的生物有效性以及酸性水稻土壤砷环境风险评价提供参考依据。     

Speciation of inorganic arsenic by electrochemical hydride generation atomic absorption spectrometry

A simple procedure was developed for the speciation of inorganic arsenic by electrochemical hydride generation atomic absorption spectrometry (EcHG–AAS), without pre-reduction of As(V). Glassy carbon was selected as cathode material in the flow cell. An optimum catholyte concentration for simultaneous generation of arsine from As(III) and As(V) was 0.06 mol l⁻¹ H₂SO₄. Under the optimized conditions, adequate sensitivity and difference in ratio of slopes of the calibration curves for As(III) and As(V) can be achieved at the electrolytic currents of 0.6 and 1 A. The speciation of inorganic arsenic can be performed by controlling the electrolytic currents, and the concentration of As(III) and As(V) in the sample can be calculated according to the equations of absorbance additivity obtained at two selected electrolytic currents. The calibration curves were linear up to 50 ng ml⁻¹ for both As(III) and As(V) at 0.6 and 1 A. The detection limits of the method were 0.2 and 0.5 ng ml⁻¹ for As(III) and As(V) at 0.6 A, respectively. The relative standard deviations were of 2.1% for 20 ng ml⁻¹ As(III) and 2.5% for 20 ng ml⁻¹ As(V). The method was validated by the analysis of human hair certified reference material and successfully applied to speciation of soluble inorganic arsenic in Chinese medicine.     

碱熔酸浸试样–碘量法测定铜冶炼白烟尘中的铜

建立碱熔酸浸试样–碘量法测定铜冶炼白烟尘中铜的方法。采用氢氧化钾–硝酸钾混合溶剂熔融试样,用盐酸浸取,以溴消除砷、锑等元素的干扰,用碘量法测定铜的含量。对滴定条件及共存元素的干扰和消除进行了验证,从而确定了最佳测定条件。实验最佳条件:4 g氢氧化钾和0.5 g硝酸钾混合溶剂;马弗炉温度650 ℃;样品称样量0.300 0 g;硫代硫酸钠标准溶液浓度0.02 mol/L。采用该实验条件,铜冶炼白烟尘中的铜测定结果相对标准偏差在0.37%~0.83%之间(n=10),样品加标回收率为98.30%~101.40%。该方法分析时间短,测定结果准确可靠,具有良好的精密度,可用于铜冶炼白烟尘中铜的测定。     

A rapid radiochemical method for antimony and arsenic : Part I. Formation of stibine and arsine by flash electrolysis

The formation of stibine and arsine affords a clean, one-step, method of separating antimony and arsenic from fission products. The development of a high-current electrolytic cell for the rapid formation of these hydrides from a hydrochloric acid electrolyte, is described. A chemical yield of 45% was achieved for both antimony and arsenic in 10 sec. The effects of pH and antimony and arsenic oxidation states were also studied. In 5 N hydrochloric acid, the chemical yield is independent of the antimony oxidation state. For arsenic however, the yield of arsine is 7 times greater for As(III) than for As(V).     

Determination of arsenic and arsenic compounds in natural gas samples

Organic arsenic compounds (trialkylarsines) present in natural gas were extracted by 10 cm³ of concentrated nitric acid from 1 dm³ of gas kept at ambient pressure and temperature. The flask containing the gas and the acid was shaken for 1 h on a platform shaker set at the highest speed. The resulting solution was mixed with concentrated sulfuric acid and heated to convert all arsenic compounds to arsenate. Total arsenic was determined in the mineralized solutions by hydride generation. The arsenic concentrations in natural gas samples from a number of wells in several gas fields were in the range 0.01–63 μ As dm^?3. Replicate determinations of arsenic in a gas sample with an arsenic concentration of 5.9 μ dm^?3 had a relative standard deviation of 1.7%. Because of the high blank values, the lowest arsenic concentration that could be reliably determined was 5 ng As dm^?3 gas. Analysis of nonmineralized extracts by hydride generation identified trimethylarsine as the major arsenic compound in natural gas. Low-temperature gas chromatography-mass spectrometry showed more directly than the hydride generation technique, that trimethylarsine accounts for 55–80% of the total arsenic in several gas samples. Dimethylethylarsine, methyldiethylarsine, and triethylarsine were also identified, in concentrations decreasing with increasing molecular mass of the arsines.     

Determination of trace arsenic in hydrofluoric acid by hydride generation and atomic absorption spectrometry

Practical procedures are given for determination of arsenic(III) and (V) in hydrofluoric acid by means of hydride generation and atomic absorption spectrometry. Arsenic(III) can be determined by direct generation of arsine with sodium borohydride in hydrochloric/hydrofluoric acid medium, arsenic(V) being only slightly reduced under the conditions used. For its determination, arsenic(V) has to be prereduced with potassium iodide, and even then its reduction to arsenic(III) and then arsine is far from complete. It is possible to determine it in presence of arsenic(III) by a difference method, but this is recommended only if the As(V)/As(III) ratio is greater than 1. Total arsenic can be determined after oxidation of As(III) and evaporation of most of the hydrofluoric acid. The limit of determination is 5 g/l for arsenic(III) and 0.25 g/l for total arsenic; the relative standard deviation is about 10%.