Study of the Toxicity of 1-Bromo-3-Chloro-5,5-Dimethylhydantoin to Zebrafish

Objective 1-Bromo-3-chloro-5,5-dimethylhydantoin （BCDMH） is a solid oxidizing biocide for water disinfection.The objective of this study was to investigate the toxic effect of BCDMH on zebrafish.Methods The developmental toxicity of BCDMH on zebrafish embryos and the dose-effect relationship was determined.The effect of BCDMH exposure on histopathology and tissue antioxidant activity of adult zebrafish were observed over time.Results Exposure to 4 mg/L BCDMH post-fertilization was sufficient to induce a number of developmental malformations,such as edema,axial malformations,and reductions in heart rate and hatching rate.The no observable effects concentration of BCDMH on zebrafish embryo was 0.5 mg/L.After 96 h exposure,the 50% lethal concentration （95% confidence interval （CI）） of BCDMH on zebrafish embryo was 8.10 mg/L （6.15-11.16 mg/L）.The 50% inhibitory concentration （95% CI） of BCDMH on hatching rate was 7.37 mg/L （6.33-8.35 mg/L）.Histopathology showed two types of responses induced by BCDMH,defensive and compensatory.The extreme responses were marked hyperplasia of the gill epithelium with lamellar fusion and epidermal peeling.The histopathologic changes in the gills after 10 days exposure were accompanied by significantly higher catalase activity and lipid peroxidation.Conclusion These results have important implications for studies on the toxicity and use of BCDMH and its analogs.

Antimicrobial M aterials: Synthesis of Reactive 5,5-Dimethylhydantoin Derivative and Application in Cellulose with Dyeing Process

The efficient and regenerable antibacterial properties of Nhalamines make them an ideal candidate for parapretion of antimicrobial textiles. In this study,a 5,5-dimethylhydantoin-based reactive N-halamine precursor, 4-( 4-( 3-( 3-hydroxypropyl)-5,5-dimethylhydantoin)-6-chloro-1,3,5-triazinylamino)-benzenesulfonate( HTB), was synthesized and characterized by ~1H-NMR. The synthesized compound was coated to cotton fabrics via reactive dye dyeing process. The coated cotton showed excellent antimicrobial activities against S. aureus( Gram-positive) and E. coli O157: H7( Gram-negative) with short contact times after exposing to diluted household bleach. The treatment method used in this study has a small effect on the tensile strength of cotton fabrics. The durability and regenerability of the chlorinated cotton samples were tested.Although the chlorine content decreased towards washing and storage,almost all of the initial oxidative chlorine levels could be regained after rechlorination.

Crystal Structure of 3-Allyl-5,5-Dimethylhydantoin

In this paper single crystals of 3-allyl-5,5-dimethylhydantoin（ADMH）have successfully extracted through recrystallization from a mixture solvents of dichloromethane and petroleum ether.By using single-crystal X-ray diffraction technique,its crystal structure has been determined to belong to monoclinic system,with space group P2（1）/n,a=0.599 53（12）,b=0.983 7（2）,c=1.529 0（3）nm,β=100.43（3）°,V=0.886 9（3）nm3,Z=4,Dc=1.260 g/cm3,F（000）=360,μ（MoKα）=0.092 mm-1,Mr=168.20,R=0.042 2 and wR=0.108 5 for 1 755 observed reflections（I〉2σ（I））.Also,its chemical formula has been confirmed as C8H12N2O2.Results of crystal structures determination for the compound show that the bond of N（1）-C（2）has a double-bond characteristic and there are intermolecular hydrogen bonds.This crystal exists in the form of dimers,in which the two constituent ADMH molecules build into an H-bond-centered symmetric pattern.

无氰镀银层水性硅溶胶封闭工艺及镀层结构与耐蚀性

[目的]镀银层往往存在孔隙,使其耐蚀性无法满足苛刻的海洋环境应用要求,因此有必要对其进行封闭处理。[方法]采用水性硅溶胶对5,5-二甲基乙内酰脲(DMH)体系无氰镀银层进行封闭,通过正交试验优化封闭处理的工艺条件。借助扫描电镜(SEM)、X射线光电子能谱仪(XPS)及电化学阻抗谱(EIS)测试分析了封闭后Ag镀层的微观结构、化学组成及耐蚀性。考察了1Cr18Ni9Ti不锈钢和GH2132合金表面Ag镀层经硅溶胶封闭后的耐酸性盐雾性能。[结果]较佳的封闭液组成和工艺条件为:丙烯酸树脂100 g/L,中性硅溶胶26 g/L,表面活性剂1 g/L,室温,时间60 s。在该条件下封闭后,Ag镀层表面疏水性和耐蚀性提高;Ag镀层的微观表面形貌未发生改变,封闭剂仅渗入镀层孔隙,而未在表面形成连续的膜。1Cr18Ni9Ti不锈钢和GH2132高温合金经“无氰镀银+水性硅溶胶封闭”处理后可以通过192 h的酸性盐雾试验。[结论]采用水性硅溶胶封闭处理可显著提高无氰镀银层的耐蚀性,对航空零部件的发展具有重要意义。

5,5−二甲基乙内酰脲体系无氰镀镉层的结构及耐蚀性

[目的]研究5,5−二甲基乙内酰脲(DMH)体系无氰镀镉层的结构及性能,为拓宽其应用提供实验数据。[方法]选用碱性DMH体系电镀镉,采用扫描电镜和X射线衍射仪分析Cd镀层的微观结构,通过电化学测试、中性盐雾试验及长期浸泡试验研究Cd镀层的耐蚀性及其腐蚀行为演变规律。[结果]DMH体系Cd镀层外观呈亮白色,晶粒呈六棱柱形,尺寸虽略大于氰化物Cd镀层,但更致密,并且在(002)晶面呈高择优取向,其织构系数达到了99.834%。DMH体系Cd镀层在3.5%NaCl溶液中的腐蚀电流密度约为氰化物Cd镀层的40%,可以经受876 h中性盐雾腐蚀。经六价铬钝化的Cd镀层在2384 h的中性盐雾试验后仍未出现红锈。长期浸泡腐蚀过程中,镉镀试样的腐蚀控制步骤及腐蚀速率会随腐蚀产物的生成和破坏而变化。[结论]碱性DMH体系Cd镀层的耐蚀性可与氰化物Cd镀层相媲美,有望用于航空结构钢部件的防护。

DMH对氯化胆碱-乙二醇体系电沉积银的影响

[目的]研究5,5-二甲基海因(DMH)作为添加剂对氯化胆碱-乙二醇(ChCl-EG)低共熔溶剂体系中银电沉积的影响。[方法]采用循环伏安法(CV)和计时电流法(CA)研究了DMH浓度对Ag还原行为和成核的影响。通过X射线衍射仪(XRD)、扫描电镜(SEM)及能谱仪(EDS)探究了DMH浓度对Ag镀层晶相结构、微观形貌和元素组成的影响,并通过塔菲尔极化曲线测试考察了DMH浓度对Ag镀层耐蚀性的影响。[结果]随着镀液中DMH的添加及其浓度的增大,银电沉积的还原(峰)电位负移,还原峰电流密度略降;在电沉积初期银的成核更接近三维瞬时成核模型,但随着时间的推移逐渐偏离三维瞬时成核模型和三维连续成核模型;镀液中添加DMH可令Ag镀层晶粒得以细化,表面形貌有所改善。DMH浓度为0.8 mol/L时所得Ag镀层最为致密,晶粒细小,耐蚀性最佳。[结论]DMH作为ChCl-EG体系的添加剂能够显著提高Ag镀层的性能。

Silica-supported 1,3-dichloro-5,5-dimethylhydantoin(DCH) as a useful reagent for microwave-assisted aromatization of 1,3,5-trisubstituted pyrazolines under solvent-free conditions

1,3,5-Trisubstituted pyrazolines are rapidly and conveniently oxidized to their corresponding pyrazoles by 1,3-dichloro-5,5- dimethylhydantoin（DCH） in solution and solvent-free conditions under microwave irradiation.The presence of silica gel as a supporting agent is shown to be effective in reducing the reaction times and increasing the yields.

1,3-Dibromo-5,5-dimethylhydantoin(DBH)/kaolin:An efficient reagent system for the synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes under solvent-free conditions

1,3-Dibromo-5,5-dimethylhydantoin, has been used as an efficient catalyst for the synthesis of 14-aryl-14H-dibenzo[a,j]- xanthenes in the presence of kaolin. All reactions are performed in the absence of solvent in relatively short reaction times in good to high yields.

Aminobromination of Ethyl α-Cyanocinnamate Derivatives with 1,3-Dibromo-5,5-dimethylhydantoin（DBDMH） as Nitrogen and Halogen Sources

1,3-Dibromo-5,5-dimethylhydantoin（DBDMH） was found to be a new and efficient nitrogen/halogen source for the aminobromination of ethyl a-cyanocinnamate derivatives catalyzed by K3PO4. The reaction afforded the aminobrominated products in high yields at room temperature, and the full regiospecificity of all the products were achieved. A possible pathway involving a Michael addition for this aminobromination was suggested.

One-pot Synthesis of α,β-Dehydroamino Derivatives from β,β-Dicyanostyrene with 1,3-Dibromo-5,5-dimethylhydantoin Promoted by Mild Base

The reaction of β,β-dicyanostyrene derivatives（l） with 1,3-dibromo-5,5-dimethylhydantoin（DBDMH） was systematicly studied. The reaction could generate different products when promoted by different mild bases. When the reaction was promoted by NaOAc（100%, molar ratio to compound 1）, β,β-dicyanostyrene derivatives could be directly converted into corresponding α,β-dehydroamino derivatives in good to excellent yields in one-pot. When the reaction was promoted by K3PO4（80%, molar ratio to compound 1）, the corresponding α,β-dehydroamino and double-α,β-dehydroamino compounds were simultaneously obtained and the total conversion of β,β-dicyanostyrene derivatives was up to 90% or higher.

Enantioselective Chlorocyclization of Olefinic Amides with 1,3-Dichloro-5,5-Dimethylhydantoin（DCDMH） Catalyzed by（DHQD）2PHAL

An efficient catalytic asymmetric chlorocyclization of olefinic amides with 1,3-dichloro-5,5-dimethylhydantoin（DCDMH） using hydroquinidine 1,4-phthalazinediyl diether（（DHQD）_2 PHAL） as organocatalyst has been developed. Series of chiral chloro substituted isobenzofuran-1（3 H）-imine derivatives were obtained in good yields（up to 85%） and enantioselectivities（up to 70% ee）.

5,5-二甲基乙内酰脲配位体系酸性镀镉工艺优化

针对无氰镀镉体系镀液稳定性差、镀层性能不佳等问题,选用5,5-二甲基乙内酰脲(DMH)为主配位剂、CdCl2为主盐研究了新型镀镉工艺。通过赫尔槽试验、阴极极化等技术研究了镉盐和DMH含量、辅助络合剂类型及浓度、pH值以及电流密度等因素的影响,优化了酸性DMH镀镉工艺方案。结果表明:酸性DMH镀镉体系中可以选择柠檬酸铵作为辅助络合剂。适当增加镉盐与DMH含量,可拓宽光亮电流密度范围,提高镉镀层致密性;增加柠檬酸铵浓度有利于提高镀速,但过多的镉盐和DMH会降低镀液稳定性。提高镀液pH值,镉沉积极化电位不断负移,有助于获得细致结晶,但pH>4后镀液易出现沉淀;此外,该体系许可的电流密度不宜超过1.5 A/dm~2。综合确定较佳的酸性DMH镀镉工艺方案为:CdCl230 g/L,DMH 60 g/L,柠檬酸铵40 g/L,KCl 30 g/L,pH=3,电流密度1.0~1.5 A/dm~2。在此体系下所得镉镀层表面结晶细致、均匀致密,晶粒尺寸为650 nm左右,镀层中Cd元素含量为95.6 wt.%。

柠檬酸铵对5,5-二甲基乙内酰脲配位体系碱性无氰镀镉的影响

选用5,5-二甲基乙内酰脲(DMH)为主配位剂开发碱性无氰镀镉体系,通过赫尔槽试验、电化学测试、扫描电镜等分析研究了柠檬酸铵作为辅助配位剂对碱性DMH镀镉体系中镉电沉积行为及镀层性能的影响。结果表明:柠檬酸铵可以拓宽碱性DMH镀镉体系的光亮电流密度窗口,阻碍镉配离子的放电还原,增大阴极极化,提高电流效率,细化镀层晶粒,改善镀层耐蚀性。少量柠檬酸铵的阴极极化作用较弱,镀层结晶不够细致;过量的柠檬酸铵会增大析氢反应,降低镀液稳定性;30 g/L的柠檬酸铵辅助配位效果较佳,所得镀层结晶细致、耐蚀性良好。

5,5-二甲基乙内酰脲含量对碱性无氰镀镉的影响

选用5,5-二甲基乙内酰脲(DMH)作为配位剂、CdO作为主盐在45钢基体上进行碱性无氰镀镉。通过阴极极化曲线测试、循环伏安分析、扫描电镜(SEM)、X射线衍射(XRD)等手段研究了DMH质量浓度对镉电沉积行为及镀层性能的影响。结果表明,随着DMH质量浓度从120 g/L增大至180 g/L,镉离子的初始沉积电位显著负移,阴极极化增强,Cd镀层结晶更加细致,耐蚀性有所改善。继续增大DMH质量浓度至210 g/L时,Cd镀层的形貌和耐蚀性变化不大,但镀液稳定性变差。当DMH的质量浓度为180 g/L时,在1.0 A/dm~2下电镀40 min时可以获得结晶细致、耐蚀性良好的Cd镀层。

金属杂质对碱性DMH体系无氰镀银的影响

通过霍尔槽试验、阴极极化曲线测试、扫描电镜(SEM)和X射线衍射(XRD)研究了不同金属杂质(包括Cu^(2+)、Ni^(2+)和Pb^(2+))对碱性5,5−二甲基乙内酰脲(DMH)体系中银电沉积行为及镀层结构的影响。结果表明,无金属杂质时,碱性DMH镀银体系的光亮电流密度区为0.5~1.0 A/dm^(2),Ag镀层结晶细致,晶粒平均尺寸为30.7 nm。3种金属杂质均会减弱碱性DMH镀银体系中银电沉积的阴极极化作用,加速银配离子的放电还原过程,导致镀层晶粒粗大,外观发灰、发黄。Cu^(2+)和Ni^(2+)会显著缩小银电沉积的工作电流密度范围,二者的质量浓度应分别控制在0.50 g/L和0.20 g/L以内。Pb^(2+)会改变银的结晶方式,使所得Ag镀层的Ag(111)晶面衍射峰减弱,Ag(200)晶面衍射峰增强,其质量浓度不宜超过0.10 g/L。

极间距和工作电压对阳极屏蔽电沉积铜定域性的影响

设计并制作了阳极屏蔽电沉积系统,采用5,5-二甲基乙内酰脲(DMH)体系镀铜液,在温度(23.5±1)℃下电沉积30 s,研究了极间距和工作电压的变化对定域电沉积效果的影响。结果表明,阳极屏蔽定域沉积区域随极间距和工作电压的增大而扩大,且极间距变化对沉积图案定域性的影响大于工作电压变化带来的影响。

高纯度5,5-二甲基海因的制备及工艺研究

高纯度低杂质的5,5-二甲基海因产品具有更高价值的应用潜质。对DMH的合成及纯化工艺进行了研究,在一定的反应条件下可制备得到较高收率的5,5-二甲基海因粗品。通过进一步设计纯化工艺:溶解脱色-过滤结晶-烘干等关键工序,可有效去除5,5-二甲基海因合成产品中的杂质,将5,5-二甲基海因含量提高至99.96%,远大于市售5,5-二甲基海因工业品的含量。本工艺简单高效、成本低廉,生产的DMH产品含量高杂质低,有望广泛应用于高要求生产领域。

焦磷酸钾对DMH无氰镀银的影响

研究以5,5-二甲基乙内酰脲(DMH)和焦磷酸钾为配位剂的无氰镀银液组成及工艺条件。在单因素研究的基础上,利用正交实验优化镀液组成;优化的镀液稳定性较好,可获得光亮细致的镀银层。讨论工艺条件对镀层外观质量的影响,确定较优的镀银工艺条件;工艺性能稳定,具有应用推广价值。

5,5′-二甲基乙内酰脲体系电沉积金(英文)

开发了以5,5′-二甲基乙内酰脲(DMH)为配位剂的无氰电镀金工艺。利用扫描电镜(SEM)和线性扫描伏安曲线对电镀时间和添加剂(由丁炔二醇、糖精和十二烷基硫酸钠组成)对镀金层表面、断面形貌和镀液性能的影响进行了测试,结果表明随着电镀时间的延长镀金层表面形貌几乎没有发生变化,光亮剂的加入增大了阴极极化同时使镀金层结晶变得细致均匀,在由HAuCl4,DMH,K3PO4和KH2PO4组成的基础镀液中金的沉积速度可达0.3μm.min-1,镀液中添加剂的加入没有影响金的沉积速度。利用X射线衍射技术(XRD)和X射线光电子能谱技术(XPS)对镀金层性能进行了测试,结果表明镀金层沿着(111)晶面择优生长并且由纯金组成。利用循化伏安曲线和旋转圆盘电极对Au(Ⅲ)在镀液中的电化学还原机制进行了研究,结果表明当研究电极为玻碳电极(GCE),镀液温度为45℃时,镀液中金的电沉积过程是受扩散控制的不可逆的过程。同时利用循环伏安曲线对镀金液的稳定性进行了分析。

二溴海因和碳水化合物水平对凡纳滨对虾生长和免疫的影响

研究了低盐度条件下,二溴海因和碳水化合物水平对凡纳滨对虾(Litopenaeus vannamei)生长和免疫的影响,共3个实验。实验1研究了二溴海因对凡纳滨对虾存活的影响,发现在0.2、5和20三个盐度水平,随着二溴海因浓度的升高,凡纳滨对虾存活率呈下降趋势;二溴海因对凡纳滨对虾的安全浓度随盐度的增加呈上升趋势。实验2和实验3研究了盐度、二溴海因浓度和饲料中碳水化合物水平对凡纳滨对虾生长和免疫的影响,结果表明:在低盐度养殖条件下,凡纳滨对虾长期生活于二溴海因环境中,可导致对虾处于应激状态,需要消耗体内较多的免疫因子,血清酚氧化酶和超氧化物歧化酶活性降低,生长速度下降,而在饲料中适量增加碳水化合物不仅可促进对虾生长又可起到饲料蛋白质节约作用。