Studies in the anthrapyridone field

It is shown that hydrogen chloride catalyzes the replacement of halogen in the reaction of halogenoanthrapyridines with aromatic amines. Cupric acetate, in the presence of potassium acetate at 80–120° C, does not catalyze the replacement of halogen in these substances. The replacement of the arylamino residues in position 6 of a number of 2, 6-diarylaminoanthrapyridines by alkylamine residues under the action of aliphatic amines, was noted.For part V, see [8].     

Oxidative dimerization of aromatic amines using tBuOI: entry to unsymmetric aromatic azo compounds

It's all the hype: An oxidative dimerization reaction of aromatic amines utilizing tert-butyl hypoiodite (tBuOI) under mild reaction conditions leads to aromatic azo compounds. The method allows access to unsymmetric aromatic azo compounds, which are difficult to prepare by conventional synthetic methods, in a selective manner.     

快速溶剂萃取-在线净化-GCMS联用分析纺织品中10种芳香胺

利用在线净化-快速溶剂萃取结合气相色谱-质谱联用技术,建立了一种快速、高效的多种致癌芳香胺类成分的样品前处理及分析方法。纺织样品中的偶氮染料在萃取池内高温和高压条件下进行氧化-还原裂解反应,裂解芳香胺产物萃取后,经池内硅藻土填料实现在线净化。10种芳香胺类物质在0.5~90 mg/L的范围内与峰面积呈线性,检测限在1.2~4.6 mg/kg之间,快速溶剂萃取处理所得10种致癌芳香胺成分的回收率在82.6%~96.3%之间,RSD范围在1.8%~4.7%之间。     

Characterisation of leather candidate certified reference materials for their mass fractions of aromatic amines

Three batches of leather samples were coloured with nine azo dyes that can yield eight proven or suspected carcinogenic aromatic amines under reduction conditions. The samples were milled to grains and bottled in jars. A group of five laboratories has established the mass fraction of the amines in a ring test using different analytical methods. The methods included a reduction step in order to cleave the azo dyes into the aromatic amines. Quantification was by standard addition: sub-samples of the leathers were spiked with known amounts of azo dyes of known purity. It was possible to establish the mass fractions of six of the eight aromatic amines in three of the leather samples.     

Determination of aromatic amines formed from azo colorants in toy products

A study for the determination of the aromatic amines formed after reduction of the azo colorants mostly used in toys was conducted. Sodium dithionite was used in the reductive cleavage of the azo group for the dyes, and the released amines were subsequently analysed by high-performance liquid chromatography with UV detection. The influence of different variables related to the reduction process was investigated by the use of a full-level factorial design, where most significant parameters as well as order interactions were studied. Reduction profiles for each colorant were obtained by studying the changes in the amount of amine obtained with different dithionite/colorant ratios. The expected aromatic amines forming azo colorants were detected, and in the presence of a nitro group a further reduction was observed. The yield of the total reduction process was determined by using standard addition of different quantities of amines to the colorants.     

分散固相萃取/气相色谱-三重四极杆串联质谱法检测纸张中的20种芳香胺

建立了纸张中的20种芳香胺的分散固相萃取/气相色谱-三重四极杆串联质谱分析方法。纸张中的偶氮染料于(70±2)℃经预处理后还原为芳香胺,向反应后的悬浮液中先加入4 mL 10 mol/L氢氧化钠溶液,将pH值由弱酸性调至碱性,再加入0.5 mL的3内标(氘代萘、2,4,5-三氯苯胺和氘代蒽)工作溶液、10 mL的叔丁基甲醚,最后加入15 g无水硫酸钠除水,振摇40 min萃取芳香胺。萃取液经分散固相萃取试剂盒(d-SPE)进一步净化、离心后,取上层清液以气相色谱-三重四极杆串联质谱法(GC-MS/MS),在多反应离子监测(MRM)模式下检测,内标法定量。目标物在各自浓度范围内线性关系良好(r~20.99),在10、20、50 ng/mL 3个加标水平下的回收率为80.7%～128%,相对标准偏差(RSDs)为0.79%～6.5%,检出限(LOD)为0.05～2.1 ng/mL,定量下限(LOQ)为0.18～5.5 ng/mL。该方法简便快捷,灵敏度高,可用于纸张中芳香胺的快速检测。     

Ultrasound assisted diazotization and diazo coupling reactions using trichlorotriazine

A high rate and efficient procedure for the synthesis of azo dyes has been developed. This concluded the sequential diazotization-diazo condensation of aromatic amines such as 4,4′-sulfonyldianiline with NaNO₂, or trichlorotriazine with coupling agents under ultrasound irradiation at room temperature. This method applied to several types of coupling agents led to corresponding azo dyes in high yield within short reaction time. The mild reaction conditions and inexpensive procedure are clear advantages of this method.     

A computational study of remote C-H activation by amine radical cations: implications for the photochemical reduction of carbon dioxide

A computational study, using density functional theory calibrated against higher-level methods, has been undertaken to evaluate tertiary amines whose radical cations might lose hydrogen atoms from positions other than the alpha carbons. The purpose was to find photochemically activated reducing agents for carbon dioxide that could be regenerated in a separate photochemical reaction. The calculations have revealed two reactions that might be suitable for this purpose. In one, the nitrogen of the radical cation makes a bond to a remote carbon with simultaneous displacement of a hydrogen atom. In the other, a remote hydrogen atom is transferred to the nitrogen, thereby creating a distonic radical cation that can lose a hydrogen atom beta to the radical site. The latter reaction is found to be particularly favorable since it apparently involves a surface crossing that allows the amine radical cation and CO2 radical anion to transform smoothly to a ground-state formate ion and an alkene. A number of structural motifs are investigated for the amines. The lower ionization potential of aromatic amines, compared to their aliphatic analogues, is desirable in that it could permit the use of longer wavelength light to drive the reaction. However, a thermochemical cycle shows that the reduction in ionization potential must be matched by an increase in proton affinity of the amine if the intramolecular hydrogen transfer is to be exothermic. Most aromatic amines do not satisfy this criterion and, hence, would have to rely on the displacement reaction for hydrogen-atom release if they were to be used as renewable reagents for CO2 reduction. Examples of specific aromatic and aliphatic tertiary amines that should be suitable for the purpose are presented, and their relative merits and weaknesses are discussed.     

高效液相色谱-质谱法测定电子电气产品塑料部件中偶氮染料释放的致癌芳香胺

采用高效液相色谱-质谱(HPLC-MS)法对电子电气产品塑料部件中偶氮染料还原裂解产生的21种芳香族伯胺进行同时测定。塑料用有机溶剂溶解或溶胀,释放其中存在的偶氮染料,在连二亚硫酸钠的强还原性环境中,偶氮染料被还原为芳香胺。用甲基叔丁基醚提取芳香胺,提取液浓缩后用甲醇-水(1：1,v/v)定容,HPLC-MS检测。采用ZORBAX Eclipse XDB C₁₈色谱柱分离,乙腈和0.1%(v/v)甲酸溶液为流动相,流速0.6 mL/min,选择离子监测(SIM)采集数据,色谱峰保留时间和特征离子定性。21种芳香胺的线性关系良好,r >0.998,方法检出限为0.5 mg/kg。除个别物质外,在空白塑料基质中的加标回收率为60.1%~129.5%,相对标准偏差小于14.0%。本研究表明电子电气塑料部件中的禁用偶氮染料还原产生的芳香胺能够被定性定量测定,本方法的准确度高,精密度好。     

Photochemical Reactions of Carbohydrate Triflates

Abstract

The photochemical reactions of eight carbohydrate trifluoromethanesulfonates (triflates) have been investigated in methanol in the presence of potassium iodide. For those compounds which do not contain an aromatic chromophore, photolysis results in two types of reaction. One type produces deoxy sugars by replacement of the trifluoromethylsulfonyloxy (triflyloxy) group with a hydrogen atom. The second type of reaction generates partially protected sugars by replacement of the trifluoromethylsulfonyl (triflyl) group with a hydrogen atom. When the triflate being irradiated also has a protecting group containing an aromatic ring (i.e., benzyl, benzoyl, or p-tolylsulfonyl group), removal of the protecting group is the exclusive reaction pathway.     

液液萃取-分散液液微萃取-气相色谱-质谱联用测定纺织废水中痕量禁用偶氮染料

建立了液液萃取-分散液液微萃取-气相色谱-质谱联用技术测定纺织废水中痕量偶氮染料的方法。废水中的偶氮染料在碱性条件下经连二亚硫酸钠还原成芳香胺后,先用叔丁基甲醚液液萃取、盐酸反萃进行预浓缩及净化;再以乙腈-氯苯体系进行分散液液微萃取,气相色谱-质谱测定。对前处理条件进行了优化,考察了酸碱度及盐效应对芳香胺萃取效率的影响,结果表明：液液萃取过程中加入30 g NaCl,分散液液微萃取过程中加入1 mL 5 mol/L的NaOH调节体系至碱性才能达到较好的萃取效率。在优化的实验条件下,21种目标物均呈现良好的线性关系,其中13种芳香胺的线性范围为0.05~10 μg/L,7种芳香胺的线性范围为0.05~5 μg/L,2,4-二氨基苯甲醚的线性范围为20~100 μg/L,相关系数为0.996~0.999。20种芳香胺的检出限可达0.05 μg/L,2,4-二氨基苯甲醚检出限为20 μg/L。印染、机织、印花等实际废水加标试验表明,方法的回收率为75.6%~115.1%。该方法富集倍数高,检出限低,适用于纺织废水中痕量禁用偶氮染料的检测。     

Strategies for continuous on-line high performance liquid chromatography coupled with diode array detection and electrospray tandem mass spectrometry for process monitoring of sulphonated azo dyes and their intermediates in anaerobic-aerobic bioreactors

On-line HPLC with diode array detection (DAD) coupled to electrospray tandem mass spectrometry (ESI-MS/MS) is presented as an integrated quality control and process integrated optimisation tool for the continuous monitoring of sulphonated azo dyes (SADs) and their intermediates in anaerobic and aerobic bioprocesses. Ion-pair RP-HPLC is found out to be more suitable for simultaneous monitoring of aromatic amines (AAs), sulphonated aromatic amines (SAAs) and sulphonated azo dyes in comparison to RP-HPLC with polar embedded phases. Monitoring of the anaerobic degradation of the diazo Reactive Black 5 displays the dependency of a two stage azo group reduction mechanism on the redox potential of the bioreactor. An autoxidation sensitive intermediate released from the anaerobic reduction is characterised by ESI-MS/MS for the first time. The functionality of the method is demonstrated by the control and evaluation of selective adaptation of bacteria to certain pollutants and the identification of unknown intermediates causing re-gaining colour released from azo dye treatment.     

Reactions of 1-acylamino- and 1-methylsulfonylamino-2-aryloxy-4-hydroxy-9,10-anthraquinones with secondary amines

Reactions of 1-acylamino-4-hydroxy-2-phenoxy-9,10-anthraquinones with piperidine resulted in replacement of the phenoxy group by piperidino, while 1-methylsulfonyl-2-aryloxy-4-hydroxy-9,10-anthraquinones reacted with secondary amines to give products of nucleophilic substitution of hydrogen in position 3.     

Self-assembled organogels based on two-component system

Organogels were produced by the self-assembly of two organogelators, 3,5-bis(dodecanoylamino)benzoic acid and aromatic amines, in nonaromatic hydrocarbon solvents, through hydrogen bonding, aromatic stacking, and van der Waals interactions. 3,5-Bis(dodecanoylamino)benzoic acid has one carboxylic acid group for hydrogen bonding with amines and two alkylamide groups that can participate in interlayer hydrogen bonding and van der Waals interactions. The shape and size of the aromatic amines have a significant effect on the gel properties as well as their structures. A variety of organogels were realized by forming complexes of 3,5-bis(dodecanoylamino)benzoic acid and various amines with an aromatic group in nonaromatic hydrocarbon solvents.     

The formation of amines in the analytical pyrolysis of nitro and azo compounds

The analytical pyrolysis of aromatic nitro and azo compounds on metal supports yields the corresponding amines, which are the major volatile products. This reduction is mainly due to effects of the support. The origin of the hydrogen under high vacuum conditions is established. It is shown that the sample preparation can be of great importance.     

Kinetic determination of aromatic amines at millimolar level

A kinetic method for the determination of aromatic amines is reported. The method involves the formation of an azo dye between 1-(4-hydroxy-6-methylpyrimidin-2-yl)-3-methylpyrazolin-5-one and a diazonium salt formed from the amine in the presence of nitrite in weakly acidic media. The reaction is monitored via the initial rate of change of the absorbance of the azo dye at 420 nm, because this is proportional to the aniline concentration.The optimum acidity and concentration of reagents were established. The concentration ranges for which the calibration lines are linear are quite large. Detection limits were estimated. The effect of several metal ions usually present in real samples, e.g. waste water, was examined to assess interference.     

Heterogeneous cobalt carbonyl-nitroarene reactions: A significant difference from the homogeneous process

Nitroarenes are converted to aromatic amines using dicobalt octacarbonyl on alumina. Product yields are dependent on the temperature at which the oxide is dried, as well as on the nature of the support. These results contrast with the homogeneous reaction which affords azo compounds.     

Reactions of 9-chloro-1,10-anthraquinone 1-dichlorophosphorylimine with N- and C-nucleophiles

9-Chloro-1,10-anthraquinone 1-dichlorophosphorylimine formed in the reaction of 1-amino-9,10-anthraquinone with PCl₅ followed by dehydrochlorination reacts with primary amines with substitution of chlorine atoms. In the case of aliphatic amines, the reaction occurs further concurrently in two directions: the addition of the amine molecule with the formation of 9,9-di(alkylamino) derivatives of the anthrone and the substitution of hydrogen atom at position 4 with the formation of 4,9-di(alkylamino) derivatives of 1,10-anthraquinone 1-imine. In the case of aromatic amines, 1-amino-9,10-anthraquinone 9-arylimines are the end products. Reactions with the anions of CH-acids containing an alkoxycarbonyl or cyano group occur with substitution in position 9 followed by intramolecular cyclization with the formation of 2-alkoxy- or 2-amino-7H-dibenzo[f,ij]isoquinolin-7-one derivatives, respectively. For preliminary communication, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1179–1184, June, 1998.     

Characterization of sulfonated azo dyes and aromatic amines by pyrolysis gas chromatography/mass spectrometry

Sixteen sulfonated and unsulfonated azo dyes as well as eleven sulfonated and unsulfonated aromatic amines were analyzed and qualitatively characterized by means of pyrolysis gas chromatography/mass spectrometry at different temperatures. Aniline and aminonaphthalene were found to be the dominant pyrolysis products of sulfonated aromatic amines and dyes. Azo dye and dye class specific key compounds such as benzidine, vinyl-p-base and 4-aminoazobenzene could be identified by pyrolysis gas chromatography/mass spectrometry of commercial acid, cationic, direct, reactive and solvent dyes. 500 degrees C was the optimal pyrolysis temperature for most of the pyrolyzed compounds. The method was applied to a dried sample of a textile wastewater concentrate from a dyeing process. Reactive azo dyes of the group of Remazol dyes and anthraquinone dyes could be identified as the major compounds of the sample. The finding of caprolactam (a printing additive) suggests that the wastewater contained effluent from a process of heat-activated printing with reactive dyes. p-Chloraniline, a banned aromatic amine, was identified. Chemical reduction of the wastewater sample prior to pyrolysis resulted in the release of volatile aromatic amines and aided the classification of several products of pyrolysis.