Thiazole, a unique heterocycle containing sulphur and nitrogen atoms, occupies an important place in medicinal chemistry. It is an essential core scaffold present in many natural Vitamin B1- Thiamine and synthetic medicinally important compounds. The versatility of thiazole nucleus demonstrated by the fact that it is an essential part of penicillin nucleus and some of its derivatives which have shown antimicrobial sulfazole , antiretroviral ritonavir , antifungal abafungin , antihistaminic and antithyroid activities.
The synthetic importance of thiazole derivatives, its reduced forms and condensed derivatives have been increased much by their recent applications as anticancer tiazofurin , anthelmintic, vulcanising accelerators mercaptobenzothiazole and photographic sensitizers. The molar ratio of the three solutes was Finally, it was recrystallized with absolute ethanol 2—3 times to obtain a purer product.
Reaction equation is illustrated in Scheme 1. The deoxygenated NaCl solution was halved in two containers. At the same time, H 2 S was gently added to the deoxygenated NaCl solution 2. High-temperature and high-pressure test: mL 5. Nitrogen was blown in for 6 h, to remove oxygen. The autoclaves were sealed.
After 2. And EDS test by the scanning electron microscope was used for quantitative analysis of element content, to determine the formation of corrosion products. Figure 1 shows the infrared spectroscopy of TZBM. It shows that the reaction is completed and the target product is successfully synthesized.
The 2. The peak of the chemical shift of protons of —CH— of benzene backbones is found at 7. The peak at 3. The peak of the chemical shift of protons of Thiazole rings is found at 2. Figure 3 shows that the initial weight of the tested TZBM sample is 9. As the temperature gradually increases, the weight of TZBM firstly is unchanged and then drops sharply and finally is unchanged again. The rate of weight loss first increases and then decreases, and reaches a maximum value of about 0.
Therefore, TZBM is of excellent temperature resistance when used in the natural gas gathering pipelines and downhole. Figure 4 shows that corrosion rate decreases with increase in TZBM concentration. In the concentration range of — ppm, the corrosion rate reduces slowly. It means that if the amount of corrosion inhibitor is small, the specimen surface cannot be fully covered.
When the concentration of the corrosion inhibitor exceeds ppm, the corrosion rate is significantly reduced. At ppm, the corrosion rate is only 0. To understand the mechanism of corrosion inhibition, it is necessary to know the adsorption behavior of the organic adsorbate on the metal surface.
Therefore, the Langmuir isotherm equation can be expressed as Eq. And in low concentration. Therefore, Eq. Considering the influence of other factors, we adapt Eq. According to Table 1 , the surface coverage is tested to allow fitting of a suitable adsorption isotherm.
The equilibrium adsorption constant K obtained from the Langmuir plot is about 0. From this analysis, TZBM prevents corrosive media from passing through single molecules adsorbed on the surface of the steel. The principle of adsorption is that the N and O atoms in the molecule contain a lone pair of electrons, which can enter the hybrid orbital of the iron atom in the steel to form a coordination bond. Because of the special structure of TZBM, this coordination bond just establishes a stable six-membered ring structure, and each molecule can form two adsorption points, as shown in Fig.
Since temperature has a great influence on the corrosion rate, to ensure the corrosion inhibition effect of TZBM, the concentration of TZBM was increased to ppm in the high-temperature and high-pressure test. Table 2 shows the results of high-temperature and high-pressure test for corrosion inhibition performance of TZBM at different concentration.
The trends of corrosion at different concentrations is shown in Fig. As the concentration increases, the corrosion inhibition efficiency gradually increases until the concentration is ppm. Because the molecular movement is violent at high temperature, it is more difficult for the corrosion inhibitor to be adsorbed on the surface of the steel. Adding more corrosion inhibitor to the solution will help increase the amount of corrosion inhibitor adsorbed on the surface of the steel to increase the corrosion inhibition efficiency.
And when the corrosion inhibitor exceeds a certain concentration, the steel surface cannot absorb more corrosion inhibitor, therefor the corrosion inhibition efficiency will not increase. Influence of corrosion inhibitor concentration on inhibitor efficiency in the high-temperature and high-pressure test. Figure 8 is the photo of the appearance of after-cleaning specimens with and without inhibitor, respectively.
The high-temperature and high-pressure test proves that TZBM has good corrosion inhibition performance at high temperature. Figure 9 shows the micro corrosion morphology of the specimens after the high-temperature and high-pressure test without being rinsed. There are large quantities of overlapping loose structures on the surface of the specimen from the test without inhibitor TZBM. The overlapping loose structures should be the corrosion products of steel.
Differently, some crystalline objects can be observed on a flat surface of the specimen from the test with ppm inhibitor TZBM. Those crystalline objects should be NaCl precipitating from the corrosion solution. From the EDS test, the surface of the specimen from blank test has It means TZBM significantly reduced the production of iron-sulfur compounds.
Through the observation of corrosion morphology, the result of adsorption behavior research is confirmed. TZBM can indeed adsorb stably on the surface of steel to block corrosive medium at high temperature. According to the weight loss experiment, the higher the concentration of inhibitor, the higher the inhibition efficiency.
The adsorbed inhibitor molecules on the steel surface blocks corrosive medium and therefore inhibits corrosion. Adsorption of the inhibitor conforms to the Langmuir isotherm model.
This shows that TZBM is an excellent corrosion inhibitor for high-temperature environment. Corrosion -Houston Tx-. Article Google Scholar. Analysis and Countermeasure on the corrosion of metal pipelines and vessels in oil fields. Petrol Plan Eng. Google Scholar. Mater Sci. Corros Protect Petrochem Indus. Synthesis of thiazole derivatives using oxidizing agents.
Thiazole and its derivatives are among the most active classes of compounds that are known for their broad spectrum of activity, e. Some drugs that already are on the market including the recent entry dasatinib possess thiazoles nucleus [ 66 ].
Compounds containing thiazole have marked their presence in a number of clinically available anticancer drugs such as tiazofurin [ 67 ], dasatinib [ 68 ], dabrafenib [ 69 ], patellamide A [ 70 ], ixabepilone [ 71 ], and epothilone [ 72 ]. Ramla et al. Structure of compound 3. Popsavin et al. A series of 5-arylidene derivatives were synthesized and evaluated for their antitumor activity. In another approach towards triple-negative breast cancer, Zhou et al. Several of these compounds also exhibited potent activities against tumor cell colony [ 76 ] Figure A series of 2- 4-benzoyl-phenoxy -N- 4-phenyl-thiazolyl -acetamides were synthesized by Prashanth et al.
The authors suggest that the effect of compound 3. Dae-Kee K et al. This series is evaluated for its ALK5 inhibitory activity [ 78 , 79 ] Figure A series of 2,4-disubstituted thiazole compounds containing N -n-butyl or N -cyclohexyl thioureido synthon at position 2 and N-substituted thiosemicarbazone moiety 3.
All of the established derivatives revealed antineoplastic activity [ 80 ] Figure Santos et al. El-Borai et al. All the synthesized compounds displayed more anticancer activity towards the selected cell line cancer, suggesting that it might be a potential alternative agent for human hepatic cancer therapy [ 82 ] Figure Fungal and bacterial resistance to antimicrobial drugs is increasing rapidly due to nonselective antimicrobial activities and a limited number of drugs.
To overcome this situation, several molecules containing thiazole are synthesized to treat bacterial and fungal infections [ 83 , 84 ]. Structure of compounds 3. Vicini et al. Compound 3. A series of thiazolyl thiazolidine-2,4-dione derivatives were synthesized by Dundar et al.
These compounds were screened for their antibacterial and antifungal activities against methicillin-resistant S. All the compounds particularly 3. Abdel-Wahab et al. The synthesized compounds were screened for their antibacterial and antifungal activities and showed a significant activity against E.
Bera et al. Synthesized pyridinyl thiazole ligand having hydrazone moiety and its cobalt complex. Both ligand and its complex were tested for antibacterial properties towards Gram-positive and Gram-negative bacteria. The results revealed that the ligand 3.
The presence of pyridinium ion in the ligand showed increased solubility of the ligand which enhances the cell penetrating ability and cell binding activity of the ligand. Hydrolysis of ligand decreases the pH of the medium which facilitates easy penetration of ligand into the cell [ 88 ] Figure Narayana et al. The synthesized compounds were screened for their antifungal activity. The derivatives of compound 3. Chimenti et al. Some of the tested compounds were found to possess significant antifungal activity when compared to clotrimazole, in particular compound 3.
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