【作者】 王鸿儒；

【导师】 周翔；

【作者基本信息】 东华大学 ， 纺织化学及染整工程， 2007， 博士

【摘要】 铬鞣废液的污染问题是制革工业面临的一个严峻问题。解决这一问题的一条有效途径就是在铬鞣前采用改性剂对胶原进行改性,通过给胶原分子上引入附加交联点和结合点以实现高吸收铬鞣。本文根据这一思路,以均苯四甲酸二酐（PMDA）和氨基硫脲（TSC）为起始原料,通过酸酐的亲核加成反应、酰氨基硫脲的碱性环化反应、三唑硫酮环的N-羟甲基化反应合成出了一种新的N-羟甲基三唑硫酮酸改性剂。主要研究了该改性剂的合成条件、结构、与胶原和铬配合物的相互作用以及用于改性后对胶原铬鞣性能的影响。在N,N-二甲基甲酰胺（DMF）和三乙胺（TEA）体系中,氨基硫脲与均苯四甲酸二酐亲核加成可得到N-硫脲基均苯四甲酰胺酸（TUPMA）。其产率受均苯四甲酸二酐与氨基硫脲和三乙胺的配比、N,N-二甲基甲酰胺的用量、反应温度和反应时间的影响。在PMDA:TSC:TEA=1:2.18:2.4 mol,DMF用量为180ml/40g反应物,温度5℃～15℃,时间48h的条件下,产率可达到92%。产物中有两个组分,其中主要组分在产物中的质量分数大于76%,主要组分的熔点为233.0℃,MS、¹HNMR、TR综合分析的结果确认,该组分的结构是2,4-二（硫脲氨基甲酰基）-1,5-苯二甲酸。将N-硫脲基均苯四甲酰胺酸的主要组分在NaOH水溶液中环化,可得到三唑硫酮苯二甲酸（DTPA）。其产率受TUPMA浓度、NaOH浓度、温度和反应时间的影响。在TUPMA浓度为0.20～0.25mol/1,NaOH浓度为0.50mol/1,反应温度75℃,反应时间8h的条件下,产率可达到80%左右。该产物的熔点为165.3℃,MS、¹HNMR和IR综合分析的结果确认,该产物的结构是4-二（1,2,4-三唑-5-硫酮基）-1,5-苯二甲酸。在水溶液中,用甲醛对三唑硫酮苯二甲酸进行N-羟甲基化,可得到本课题的目标产物N-羟甲基三唑硫酮苯二甲酸（DHTPA）。在pH值8.2～8.5,温度50℃,时间24h的条件下,无论是DTPA:甲醛=1:4.4mol,还是DTPA:甲醛=1:2.2mol,得到的产物均为二羟甲基化产物,产率可达到74%～78%。该产物的熔点为172.8℃,MS、¹HNMR和IR综合分析的结果确认,该产物的结构是2,4-二（1-羟甲基-1,2,4-三唑-5-硫酮基）-1,5-苯二甲酸。将DHTPA与胶原、去氨基胶原、去胍基胶原、羧甲酯化胶原、去氨基去胍基胶原及甘氨酸反应,通过收缩温度测定、等电点测定、酸碱滴定、氨基酸分析、DSC分析、毛细管电泳分析、红外光谱分析、元素分析等方法,研究了DHTPA与胶原的相互作用。结果表明:DHTPA与胶原可以在一个较宽的pH值和温度范围内发生反应,使胶原的收缩温度大幅度提高并给胶原引入大量的羧基。该反应受pH值、温度、DHTPA用量和时间的影响。在pH值8.0,温度33℃,DHTPA用量为7%,时间24h的条件下,可将胶原的收缩温度由53℃提高到78℃,将胶原的羧基含量由1.27mmol/g胶原提高到1.85mmol/g胶原。胶原分子上的氨基是DHTPA的主要共价交联点和结合点,对胶原收缩温度的提高和胶原与DHTPA的结合起着决定作用。胶原分子上的羧基和胍基,在pH值8.0左右,既不是DHTPA的共价键交联点,也不是DHTPA的共价键结合点。胶原分子上的咪唑基和酚环与DHTPA可形成耐酸水解的,化学上不可逆的结合,但由于这两种氨基酸在胶原中的含量很低,因此对改性后胶原收缩温度的提高以及羧基含量的增加贡献不大。DHTPA通过其分子上的N-羟甲基与胶原的氨基结合。每个DHTPA分子可通过一个羟甲基与胶原的一个氨基结合（单点结合）,也可通过两个羟甲基与胶原的两个氨基结合（双点结合）。本试验条件下,在与胶原结合的DHTPA中72.4%的DHTPA与胶原以单点形式结合,27.6%的DHTPA与胶原以双点形式结合。DHTPA与氨基结合后可使氨基减少0.37mmol/g胶原,羧基增加0.58mmol/g胶原,可将胶原的等电点由5.1降低到4.0。DHTPA与胶原氨基的反应是二级反应。反应速率常数随反应pH值和温度的提高而增大。在pH值8.0时,反应的活化能为39.307 kJ/mol,与一般化学反应相比,活化能偏低,反应容易进行。将DHTPA与硫酸铬配合物反应,通过酸碱滴定、离子交换分析、DSC分析、紫外光谱分析和红外光谱分析,研究了DHTPA与铬配合物的相互作用。结果表明,在一定的条件下,DHTPA分子上的羧基可进入硫酸铬配合物内界,取代内界的水分子,与铬离子发生配位。在DHTPA与Cr³⁺的摩尔比大于0.06:1时,经过长时间静置,DHTPA与硫酸铬配合物可发生配聚,生成一种不溶于水的浅蓝绿色配聚物。用DHTPA对胶原改性后进行铬鞣,通过铬的吸收率、铬的固定率、坯革物理机械性能等指标的测定,研究了DHTPA对胶原铬鞣性能的影响。结果表明,采用DHTPA对胶原改性,能大幅度提高铬鞣时胶原对铬的吸收率、固定率及铬鞣胶原的收缩温度。在DHTPA用量为湿胶原质量7%的条件下,常规铬鞣时可将铬的吸收率由72.70%提高到98.91%,将铬的固定率由68.10%提高到86.26%;两步铬鞣时可将铬的吸收率由86.80%提高到99.09%,将铬的固定率由76.07%提高到90.21%。由于胶原对铬的吸收率和固定率的提高,常规铬鞣时可将标准铬粉的用量由传统的6%减少到4%,。两步铬鞣时可将标准铬粉的用量由传统的6%减少到3%,这时铬的吸收率和固定率还会进一步提高。采用DHTPA对胶原进行改性处理,可明显提高铬鞣后铬在蓝湿革各层中的含量,但基本上不改变铬在蓝湿革各层中的分布规律。除伸长率略有降低外,也不会对铬鞣坯革的主要物理性能产生明显的影响。改性处理不会明显增加坯革中游离甲醛的含量。除用于铬鞣前胶原的改性外DHTPA还可以用于铝鞣前胶原的改性。其中间体TUPMA与乙二醛配合也可用于铝鞣前胶原的改性处理。使用后能明显提高铝鞣革的收缩温度、染浴稳定性和强度。对DHTPA进行抑菌和杀菌试验的结果表明,DHTPA对金黄色葡萄球菌和大肠杆菌都有一定的抑制和杀灭作用,对金黄色葡萄球菌的最低抑菌和灭菌浓度分别为0.25%和2%,对大肠杆菌的最低抑菌和灭菌浓度分别为0.5%和4%。以上研究结果表明,用DHTPA对胶原进行改性,可大幅度提高铬鞣时胶原对铬的吸收率和固定率,减少铬的排放。如果在改性后采用两步铬鞣或少铬鞣制方法鞣制,还有可能使铬鞣废液不用处理,与其它工序废水混合后直接达到排放标准,实现清洁铬鞣。因此,DHTPA在制革工业中具有十分广阔的应用前景。更多还原

【Abstract】 The pollution from the chrome tanning effluent has become increasingly a serious problem that faces leather industry.To solve this problem,one of the routes with good potential for success is to treat collagen with special modifier to implement high exhaustion chrome tannage by simply providing additional cross-linking sites or binding sites for chromium.On the basis of these principles and requirements,in this paper,a new modifier has been synthesized from pyromellitic dianhydride and thiosemicarbazide by the nucleophilic addition of anhydride,the cyclization of acyl thiosemicarbazide in alkaline solution,and the N-hydroxymethylation of the triazole-thione.Its synthesis and structure,its interaction with collagen and chromium complexes,as well as its effect on chrome tanning properties,have been studied.The nucleophilic addition of thiosemicarbazide（TSC）to pyromellitic dianhydride（PMD）in DMF and triethylamine（TEA）produces N-thiouriedopyromellitamic acid（TUPMA）which consists of two isomers.Its yield is influenced by the molar ratio of PMDA to TSC and TEA,the amount of DMF,the temperature and the duration of the reaction.A higher yield（92%）can be obtained when the molar ratio of PMDA to TSC and TEA is 1:2.18:2.4,and the reaction is carried out in DMF 180ml/40g reactant at 5℃-15℃for 48h.The percentage of its main component is more than 76%.Its melting point is at 233.0℃.Its structure, 2,4-di-（thioureido-amino-formoyl）-1,5-phthalic acid,has been confirmed by MS spectra,¹HNMR spectra,IR spectra and elemental analysis.The cyclization of the main component of TUPMA in aqueous NaOH forms 2,5-di-（1,2,4-triazole-5-thione）-1,4-phthalic acid（DTPA）which has a melting point at 165.3℃.The structure of DTPA has been confirmed by MS spectra,¹HNMR spectra and IR spectra.Its yield is influenced by the concentration of TUPMA and NaOH,the temperature and the duration of the reaction.A higher yield（about 80%） can be obtained when 0.20-0.25 mol/1 of TUPMA is refluxed in 0.5 mol/l of NaOH solution at 75℃for 8h. The N-hydroxymethylation of DTPA with formaldehyde in aqueous solution gives 2,4-di-（1-hydroxymethyl-1,2,4-triazole-5-thione）-1,5-phthalic acid（DHTPA） which has a melting point at 172.8℃.The structure of DHTPA has been confirmed by MS spectra,¹HNMR spectra and IR spectra.Whether the molar ratio of DTPA to formaldehyde is 1:2.2 or 1:4.4,a higher yield（74-78%）can be obtained when the reaction is carded out in pH8.2-8.5 at 50℃for 24h.The synthesized modifier（DHTPA）has been reacted with collagen,deaminated collagen,deguanidinated collagen,esterified collagen,deaminated and deguanidinated collagen,and glycine.The interaction of DHTPA with collagen has been studied by shrink temperature determination,isoelectric point determination, acid-base titration,amino acid analysis,DSC analysis,capillary electrophoresis,IR spectra and elemental analysis.It has been found that DHTAP can react with collagen in a wide range of pH value and temperature to increase the shrink temperature and the carboxyl groups of collagen.The increase in shrink temperature and carboxyl groups is influenced by the pH value,temperature,DHTPA dosage,and the duration of reaction.An increase in shrinkage temperature from 53℃to 78℃and an increase in carboxyl groups from 1.27 mmol/g collagen to 1.85 mmol/g collagen can be obtained when the reaction is carried out in pH8.0 with 7%of DHTPA at 33℃for 24 h.The amino groups of collagen are main covalent cross-linking sites and binding sites for DHTPA,and play a dependent role in the increase of shrinkage temperature and carboxyl groups.The guanidino groups and carboxyl groups of collagen are neither covalent cross-linking sites nor binding sites for DHTPA in the neighborhood of pH8.The imidazole groups and phenol groups in collagen can form irreversible covalent binding with DHTPA,which could not be hydrolyzed by acid.However, they scarcely attribute to the increase in shrinkage temperature and carboxyt groups because they are very few in quantity.Each DHTPA molecule can either combine with one amino group by its one N-hydroxymethyl group（binding on single site of collagen）,or combine with two amino groups by its two N-hydroxymethyl groups （binding on two sites of collagen）.In the present experiment,72.4%of DHTPA has been bound on the collagen by two sites,and 27.6%of DHTPA has been bound on the collagen by one site.The 0.37 mmol of amino groups has been modified,and 0.58 mmol of carboxyl groups has been introduced in 1 g of collagen.The isoelectric point of collagen has been reduced from 5.1 to 4.0.Kinetics studies show that the binding of DHTPA on amino groups of collagen could be described as a second order reaction.The rate constant increases with the increase in pH value and temperature.Activation energy of the reaction of DHTPA with amino groups of collagen is 39.307 kJ/mol at pH8.0,and is lower than the usual. Thus the reaction is easy to take place.The synthesized modifier has been reacted with chromium sulfate complexes, and their interaction has been studied by acid-base titration,ion exchange analysis, DSC analysis,UV spectra and IR spectra.The results show that under certain conditions carboxyl groups of DHTPA can enter into the complexes and take the place of H₂O in the complexes to coordinate with the chromium ions.When the DHTPA dosage is more than a 0.06/1 molar ratio of DHTPA to Cr³⁺,the coordination polymerization between the DHTPA and the complexes would occur,and an insoluble co-polymer with a pale blue green color would be obtained after settlement for a long term.Collagen has been treated with DHTPA and then tanned with chromium complexes,and the effect of DHTPA on chrome tanning properties has been investigated by determining the chrome absorptivity and fixation as well as the physical properties of the crust.The results show that the treatment causes significant increases in the chrome absorptivity and fixation as well as shrink temperature during subsequent chrome tanning.In conventional chrome tanning process,the chrome absorptivity can be increased from 72.70%to 98.91%,and the chrome fixation can be increased from 68.10%to 86.26%by treating collagen with 7%DHTPA.In two-stage chrome tanning process,the chrome absorptivity can be increased from 86.80%to 99.09%,and the chrome fixation can be increased from 76.07%to 90.21%by the same treatment.Because of the enhancement in chromium absorptivity and fixation,the dosage of normal chrome powder can be reduced from 6%to 4%in conventional process,and can be reduced from 6%to 3%in two-stage chrome tanning process,and thus the chrome absorptivity and fixation can be enhanced further.The treatment causes an increase in chrome content of wetblue but could not change the distribution of chrome in various lays.The physical properties of crust leather remain unchanged on the whole after the treatment except for a slight reduction in extensions.The free formaldehyde in crust leather is not nearly increased by the treatment.DHTPA as well as its intermediate TUPMA can also be used for pretreating collagen before aluminium tanning.The shrink temperature and the dye-bath stability as well as the strength of the leather can be significantly improved when collagen is pretreated with DHTPA or a collaboration of TUPMA with glyoxal.Inhibitory and bactericidal activities of DHTPA have been tested against Staphylococcus aureus and Escherichia coli.To a certain degree,DHTPA shows inhibitory and bactericidal activities against the selected microorganisms.The minimal inhibitory concentration and minimal bactericidal concentration of DHTPA for Staphylococcus aureus is respectively 0.25%and 2%,and for Escherichia coli is respectively 0.5%and 4%.All the above results indicate that the chromium absorptivity and fixation can be significantly enhanced by applying DHTPA to the pretreatment of collagen. Therefore it is possible that the chrome tanning effluent can be directly discharged legally without any treatment after dilution with waste water from other processes if the pretreatment with DHTPA or its intermediate is used for two-stage and less chrome tanning processes.The DHTPA as well as its intermediate has a good potential for applying in leather industry.更多还原