稳定同位素标记甲基毒死蜱-D_6的合成研究

甲基毒死蜱是农业生产上常用的有机磷农药之一,在农药残留检测中引起广泛关注。本文以三氯硫磷为起始原料和价廉易得的甲醇-D_4作为稳定同位素标记源,经过两步亲核取代反应合成重要的同位素标记中间体O,O-二甲基硫代磷酰氯-D_6。在两相反应体系中,利用相转移催化剂催化同位素标记中间体:O,O-二甲基硫代磷酰氯-D_6与3,5,6-三氯吡啶-2-醇合成稳定同位素标记甲基毒死蜱-D_6,可作为农药残留检测用的内标试剂。优化反应原料摩尔比、溶剂等实验条件。该合成路线安全可靠,操作简单,对设备无特殊要求,适合实验室规模合成。产品经~1H NMR、GC、GC-MS结构表征确定为甲基毒死蜱-D_6。以消耗的甲醇-D_4计算,甲基毒死蜱-D_6的总收率为44.2%,纯度为98.3%,丰度99.0atom%D。     

同位素标记敌百虫-甲氧基-D_6和敌敌畏-甲氧基-D_6的合成

以CD3OD为同位素源,经与三氯化磷酯化得到亚磷酸二甲酯,再进一步与三氯乙醛加成得到敌百虫-甲氧基-D6,碱解脱去氯化氢分子,重排后生成敌敌畏-甲氧基-D6。以消耗CD3OD计算稳定同位素标记敌百虫-甲氧基-D6和敌敌畏-甲氧基-D6提纯后总收率分别为57.7%和47.3%。产物经高效液相色谱(HPLC)、质谱(MS)和核磁(NMR)等仪器的鉴定为目标物质,化学纯度大于98.0%,同位素丰度高于98.0%,可作为食品安全领域检测用同位素内标试剂。     

13C-甲醇的制备

采用自制的催化剂和自行设计的高效催化反应器,用催化加氢的方法,以Ba¹³CO₃为原料制备了¹³C-甲醇。所得甲醇水溶液在微型高效精馏反应器中进一步提纯后,得到的¹³C-甲醇化学纯度＞99.5%。实验设计的合成路线反应条件温和,同位素利用率＞90%。¹³C-甲醇经色质联用（GC-MS）和核磁（¹H NMR）检测,¹³C同位素丰度＞97%,¹³C-甲醇的同位素丰度与原料相比降低＜1%。以上结果表明,采用自制的催化剂和自行设计的高效催化反应器,成功地用催化加氢的方法,制备得到了¹³C-甲醇。     

稳定同位素~(13)C标记乙醇

以Ba13CO3为原料,采用碳化锂方法制备乙炔,再经催化水合法和NaBH4还原,制备了13C-乙醇。考察了反应温度、助催化剂等合成工艺对产物收率的影响。设计的合成路线反应条件温和,总收率高于50%。产品经红外、色谱和核磁检测,化学纯度99%,13C同位素丰度95%,产物的同位素丰度相对原料而言降低3%。     

稳定同位素~(13)C或D标记对甲氧基苯甲酸的合成

稳定同位素标记对甲氧基苯甲酸是防腐剂、香料及药物等稳定同位素标记内标试剂合成中的重要中间体。本文以尼泊金乙酯(对羟基苯甲酸乙酯)和碘甲烷-~(13)C或碘甲烷-D3为原料,碱性条件下经2步反应合成对甲氧基苯甲酸-甲氧基-~(13)C和对甲氧基苯甲酸-甲氧基-D3。通过单因素实验确定适合的反应温度、物料摩尔比、反应时间,优化工艺参数为:反应温度为80℃,物料摩尔比n(碘甲烷-~(13)C/D3)∶n(尼泊金乙酯)=1.15∶1,反应时间为6h。产品经液质联用仪(LC-MS)测试化学纯度和同位素丰度、经核磁共振(1 H NMR)进行结构确认,对甲氧基苯甲酸-甲氧基-~(13)C的收率为91.12%,碘甲烷-~(13)C利用率为79.32%,产品熔点为186.5~187.8℃,化学纯度为99.1%,~(13)C同位素丰度为99.0%;标记对甲氧基苯甲酸-甲氧基-D3的收率为90.49%,碘甲烷-D3利用率为78.70%,产品熔点为186.3~188.1℃,化学纯度为99.0%,D同位素丰度为98.1%。     

磺胺氯哒嗪-苯环-13C6的合成

为研究稳定同位素标记的磺胺氯哒嗪-苯环-¹³C₆的合成路线,制备同位素内标试剂,用于检测动物源性食品中磺胺类药物残留,以苯-¹³C₆为稳定同位素标记来源和起始原料,通过硝化、硝基还原、酰化、磺化以及缩合、水解6步反应合成磺胺氯哒嗪-苯环-¹³C₆。产品结构经核磁共振波谱(NMR)和质谱(MS)等仪器表征确定,产品纯度>98.0%,同位素丰度>99.0atom%¹³C,可以作为内标试剂用于磺胺氯哒嗪的定性定量分析。     

稳定同位素13C或D标记对甲氧基苯甲酸的合成

稳定同位素标记对甲氧基苯甲酸是防腐剂、香料及药物等稳定同位素标记内标试剂合成中的重要中间体。本文以尼泊金乙酯(对羟基苯甲酸乙酯)和碘甲烷-¹³C或碘甲烷-D₃为原料,碱性条件下经2步反应合成对甲氧基苯甲酸-甲氧基-¹³C和对甲氧基苯甲酸-甲氧基-D₃。通过单因素实验确定适合的反应温度、物料摩尔比、反应时间,优化工艺参数为：反应温度为80 ℃,物料摩尔比n(碘甲烷-¹³C/D₃)∶n(尼泊金乙酯)=1.15∶1,反应时间为6 h。产品经液质联用仪（LC-MS）测试化学纯度和同位素丰度、经核磁共振（¹H NMR）进行结构确认,对甲氧基苯甲酸-甲氧基-¹³C的收率为91.12%,碘甲烷¹³C利用率为79.32%,产品熔点为186.5~187.8 ℃,化学纯度为99.1%,¹³C同位素丰度为99.0%;标记对甲氧基苯甲酸-甲氧基-D₃的收率为90.49%,碘甲烷-D₃利用率为78.70%,产品熔点为186.3~188.1 ℃,化学纯度为99.0%,D同位素丰度为98.1%。     

~(13)C_3-三聚氰酸、~(15)N_3-三聚氰胺的合成工艺研究

研究了以稳定性同位素标记物13C-尿素和15N-氯化铵为原料制备质谱检测用内标物13C3-三聚氰酸、15N3-三聚氰胺的合成工艺;考察了温度、压力、溶剂等对产品收率的影响,优化了合成工艺,以良好收率合成了同位素内标试剂13C3-三聚氰酸和15N3-三聚氰胺。产品经高效液相色谱(HPLC)、质谱(MS)检测,化学纯度99%,同位素丰度98%。以上结果提示,所合成的13C3-三聚氰酸和15N3-三聚氰胺可作为同位素内标使用。     

13C1-DDT的合成及结构表征

以氯苯和13C-乙醇为主要原料,浓硫酸为催化剂,合成了13C1-DDT,产物经DSC、FT-IR、1H NMR、13CNMR、MS分析表征.结果表明,产物化学纯度＞99%,同位素丰度＞99%,产率为51%.所得产物为目标产物,可用作同位素内标.     

胸腺嘧啶-~(15)N_2的合成与表征

以甲酸乙酯和丙酸乙酯为原料,在金属钠存在下缩合得到中间体2-甲酰丙酸乙酯,中间体在酸催化下与同位素尿素-15 N2缩合,在甲醇钠作用下环化反应得到胸腺嘧啶-15 N2。合成方法操作简单,工艺流程短,副产物少,收率可达80%,15 N同位素丰度稳定。产物经HPLC、IR、MS、1 H NMR和13 C NMR表征,结果表明:产物化学纯度99%,15 N同位素丰度98atom%。     

D_(12)-孔雀石绿的合成

以CD_3OD为起始原料,经甲基化、缩合、氧化等步骤合成稳定同位素标记D_(12)-孔雀石绿。以消耗CD_3OD计算,稳定同位素标记D_(12)-孔雀石绿的总收率为50.1%。产品结构经高效液相色谱(HPLC)、质谱(MS)及核磁共振波谱(NMR)等仪器表征确定,D_(12)-孔雀石绿色谱纯度高于99.0%,氘同位素丰度大于99.0%,结果表明,D_(12)-孔雀石绿可作为食品安全领域检测用同位素内标试剂。     

氘标记盐酸苯环壬酯的合成

为了开展盐酸苯环壬酯及其光学异构体药代动力学研究,确定代谢途径,进行代谢差异比较,对盐酸苯环壬酯进行了稳定同位素氘标记合成研究。以五氘溴苯为原料,先由格氏反应生成D代中间体α-环戊基-α-D₅-苯基羟乙酸乙酯,再经三步反应得到定位标记的盐酸氘代苯环壬酯。该合成路线简捷,同位素原料易得,引入标记原子的步骤短,反应条件较易控制,氘丰度达99%,经质谱、核磁确证结构与盐酸苯环壬脂一致。     

同位素稀释质谱法测定空心玻璃微球内氘气总量

作为惯性约束核聚变(ICF)第一代靶丸,空心玻璃微球(HGM)内充燃料气体的组分、比例和密度均有严格要求,气体总量的测定至关重要。介绍了同位素稀释质谱法(IDMS)测定空心玻璃微球内氘气气体总量的分析方法。该方法采用氢气为稀释剂,活性炭作为吸附剂制备氘气和氢气的混合气体,用质谱计测定样品中氢同位素丰度。通过热力学公式推导、计算,求得HGM内氘气摩尔数。实验结果表明:用IDMS法测量HGM内痕量氘气总量切实可行,其测量下限为10-8 mol,测量结果的相对标准偏差小于5%(n=4或3,按照极差法计算),符合测量要求。     

Analysis of the Possibility of Using Fuel Based on Reclaimed Uranium in VVÉR Reactors

A current problem is to show that reclaimed uranium can be, in principle, brought into the VVÉR fuel cycle. The possibility of using fuel based on reprocessed uranium in VVÉR is analyzed. The requirements for the initial isotopic composition of test batches of fuel pellets with 4% effective enrichment are determined, the compensation coefficient is calculated, the requirements for monitoring the isotopic composition are determined, and the technlogy for fabricating fuel pellets from relaimed fuel is determined. It is shown that the basic neutron-physical characteristics satisfy the restrictions adopted in the VVÉR-440 and -1000 designs. The effect of radiation on the public and the environment as a result of switching to fuel fabricated from reclaimed uranium is the same as for the standard oxide fuel.     

Isotopic Enrichment and Thermal Neutron Cross Section Measurement of Erbium-167

The thermal neutron cross section of Er167 has been obtained by measuring the relative number of Erl68 atoms formed by radiative neutron capture, when isotopically pure Er167 samples were exposed to a highly-thermalized neutron flux. A four-stage mass spectrometer was used to provide a 106/1 isotopic enrichment of Er167. It was also employed it measure the postirradiation Er168/Er167 isotopic ratios of the samples, which were placed in the D2O moderated Argonne CP-5 reactor. The integrated neutron flux, and effective neutron temperature in this reactor were also monitored mass spectrometrically, by observing isotopic ratio changes in nuclides whose cross section as a function of temperature are known. Two rare earth isotopes Sm149 and Gd157, were selected as the "non-l/v" absorbers that yielded this data. The effective neutron cross section of Er167 was found to be 740 ± 21 barns, at an effective neutron temperature of 42.8 + 2.5°C, with an integrated neutron flux of 3.37 ± 0.08 × 1019 neutron/cm2. The thermal (2200 m/sec) neutron cross section of Er167 was then calculated to be 699 ± 20 barns.     

铀离心浓缩厂分离功率在线监测技术研究

利用研制的铀丰度在线监测装置对铀浓缩厂工艺管道中精料和贫料铀丰度进行在线监测,同时利用孔板流量计在线监测浓缩厂精料端工艺管线UF_6精料流量,然后利用分离功率方程计算得到分离功率。现场实验表明:在均不考虑物料损耗情况下,分离功率在线监测结果与铀浓缩厂分离功率申报值的相对偏差小于2.0%。     

Stable isotopes applied as water tracers for infiltration experiment

The δD and δ18O vertical profiles of soil water were measured prior to and after a rainfall event.Mechanisms of soil water movement were deciphered by comparing the soil water isotope profiles with the isotopic composition of precipitation.The results show that evaporation at the upper depth led to enrichment of the heavy isotopes.Compared to the loess profile,the shallow soil water of sand profile is relatively enriched in D and 18O due to macro-pore and low water-holding capacity.The precipitation is infiltrated into soil in piston mode,accompanied with significant mixing of older soil water.The preferential fluid flow in loess was observed at depths of 0-20 cm,caused by cracks in the depths.The hydrogen and oxygen isotopic compositions in outflow are close to the precipitation,which shows a mixing of the precipitation and old soil water,and indicates that the isotopic composition of outflow water is mainly controlled by that of the precipitation.The δD and δ18O in outflow decreased with time until stable δ values of outflow are close to those of the precipitation.