The Study On Chemometrics-ultraviolet Spectroscipy On Four Categories Of Disubstitued Benzene Compound Isomers

Disubstituted benzene compounds are widely used in the pharmaceutical industry and chemical industry, each of the disubstituted benzene compounds has three kinds of isomers which are ortho-position, meta-position and para-position. It is important to use an easy analytical tool. The prediction research by combining 14 kinds of stoichiometry with ultraviolet spectrum is an effective means. Compared the Results of 14 kinds of chemometric methods of the four categories of disubstituted benzene compounds to analyse the effect of different substituents.The conclusions are as follows:(1)This sectionn mainly focuses on the study of methylaniline, fluoroaniline, methoxyaniline, chloroaniline and nitroaniline. The experimental results show that the five kinds of compounds have good linearity and additive with the selection detection wavelength and concentration range. The correlation of different substiruents are that,-CH3>-F>-OCH3>-Cl>-NO2. The absorbance of different substituents are that,-NO2>-Cl>-OCH3>-CH3>-F. The results show that, in addition to methyl aniline, the measurement results with other compounds of the above conclusions are consistent. Thus nitroaniline is better, and the measurement result of fluoroaniline is relatively poor. Among the 14 kinds of chemometrics-UV methods,6 methods are suitable for fluoroaniline.10 methods are appropriate for chloroaniline. Methoxyaniline can be measured in 10 methods. Only 1 method can not be used for the determination of nitroaniline. And all the methods can be applied for determining the concentration of methylaniline.The methods of PLS and PCR are better, and BP and KF are relatively poor.(2)This section mainly includes 7 kinds of compounds, which are fluorobenzaldehyde, methylbenzaldehyde, methoxybenzaldehyde, chlorobenzald-ehyde, hydroxybenzaldehyde, nitrobenzaldehyde and bromobenzaldehyde. The result shows that the 7 kinds of compounds have good linearity and additive with the selection detection wavelength and concentration range. The correlation of different substituents were that,-F>-CH3>-Cl>-Br>-NO2>-OCH3>-OH. The absorbance of different substituents are that,-CH3>-OH>-OCH3>-NO2>-Cl>-Br>-F. The results show that, in addition to methylbenzaldehyde and methoxybenzaldehyde, the measurement results with other compounds of the above conclusions are consistent. Thus hydroxybenzaldehyde is better, and the measurement result of fluorobenzaldehyde and methylbenzaldehyde are relatively poor. Among the 14 kinds of chemometrics-UV methods, only 1 method can not be used for the determination of fluorobenzaldehyde.7 methods are suitable for the determination of methylbenzaldehyde.8 methods are appropriate for determining the concentration of methoxybenzaldehyde. The suitable methods for chlorobenzaldehyde were the same with fluorobenzalde-hyde. And all the methodS can be applied for determining the concentration of hydroxybenzaldehyde, nitrobenzaldehyde and bromobenzaldehyde.The methods which are PLS?PCR and RBF are better, and K and KF are the worst.(3)Xylene, cresol, methylaniline, methylbenzaldehyde, methyl benzoic acid, chlorotoluene and bromotoluene are involved in this section. The result shows that the 7 kinds of compounds have good linearity and additive with the selection detection wavelength and concentration range. The correlation of different substituents were that,-CH3>-Br>-NH2>-OH-Cl>-CHO-COOH. The absorbance of different substituents are that,-CHO>-COOH>-OH>-NH2>-Cl>-Br>-CH3. The results show that, in addition to the substance of methyl benzoic acid, the measurement results with other compounds of the above conclusions are consistent. Thus methylaniline is better, and the measurement result of haloid methylbenzenes is relatively poor. Among the 14 kinds of chemometrics-UV methods,8 methods are appropriate for xylene and bromotoluene.10 methods are suitable for the substance of cresol. All the methods can be applied for determining the concentration of methylaniline. Only 2 methods can be used for the determination of chlorotoluene.7 methods are suitable for the analysis of methylbenzaldehyde and 3 methods for methyl benzoic acid. The method which are PLS?PCR and RBF are better, and K and KF are worse.(4)This section mainly include 10 kinds of compounds, which are fluoro-aniline, fluorobenzaldehyde, chloroaniline, chlorophenol, chlorobenzaldehyde, chlorotoluene, nitrochlorobenzene, nitrobromobenzene, bromobenzaldehyde and bromotoluene. The result shows that the 10 kinds of compounds have good linearity and additive with the selection detection wavelength and concentration range. The electronic-donating of auxochrome substituents were that,-NH2>-OH>-CH3>-Br-Cl>-F.-NO2 and-CHO are chromophore. The results show that, the bittern benzene compounds that contain nitro have a better measurement results, contrary to that contains methyl. Among the 14 kinds of chemometrics-UV methods, only 1 method can be used for the determination of fluoroaniline.7 methods are suitable for the determination of fluorobenzaldehyde, all the methods can be applied for determineing the concentration of chloroaniline and nitrochlorobenzene.9 methods are appropriate for nitrochlorobenzene. The amount of the methods that can be used for the deteminnation of chlorobenzaldehyde, chlorotoluene, nitrobromobenzene, bromobenzaldehyde and bromotoluene are 12,2,13,11 and 5. The methods which are PLS. PCR and RBF have better results, but BP and KF are worse.