| As China's urbanization accelerating and people's living standards increasing, the water consumption of urban industrial production and living is rapidly increasing, coupled with serious water pollution, makes an already tense contradiction between water resources supply and demand become more prominent and sharp. Strengthen the facilities construction and operation management of industrial circulating cooling water and improve the recycling rate of industrial water is imminent. As continuous evaporation of water in the circulating cooling process, make the concentration and precipitation of some insoluble salts and produce scaling, resulting in reducing heat transfer efficiency of heat transfer equipment, pipe blockage and corrosion under the scale, affecting the normal operation of the system. Therefore, by adding chemical inhibitors to inhibit equipment scaling effectively is one of the methods used widely at home and abroad in recent years. phospherous antiscalant - for organic phosphonic acid agent with a wide range of pH, better stability of chemical and thermal, hard to be hydrolyzed, while there was other characteristics of "synergistic effect" and the " threshold effect ", has been widely used in the industrial circulating cooling water treatment at home and abroad. However, there is higher phosphorus content in the phosphorus scale inhibitor ,can easily lead to other problems such as eutrophication of water body, so developed a new highly effective environment-friendly green scale inhibitor with non- phosphorus, lower-phosphorus, which have become hot areas at home and abroad currently.In this paper, target product N-(6– amino hexyl) -1,6– hexanediamine penta phosphorous methylene acid inhibitor was in one step synthesized with N-(6– amino hexyl) -1,6– hexanediamine, phosphorous acid, formaldehyde as raw materials, following the principle of the Mannich. The target product were optimized by apply the means to single factor analysis and orthogonal synthesis and was purified by ethanol recrystallization method, the structure of the target product was characterized by use the means to elemental analysis, infrared spectrum analysis and nuclear magnetic resonance spectrum analysis. At the same time, apply static scale inhibition tests, such as common organic phosphonic inhibitors hydroxy ethylidene diphosphonic acid (HEDP), amino trimethylene phosphonic acid (ATMP), ethylene diamine tetramethylene phosphonic acid (EDTMP), diethylene triamine penta methylene phosphonic acid (DTPMP) as contrast agents, in the condition of same water quality and differrnt adding concentration, the scale inhibition performance of the monomer and composite material were studyed respectively for calcium carbonate and calcium sulfate scale, and its inhibition mechanism was discussed by using scanning electron microscopy. At the same time, apply rotating hanging plate tests method, such as common organic phosphonic inhibitors ATMP and EDTMP as contrast agents, the monomer on carbon steel corrosion inhibition was investigated.The results showed that:1) On the basis of studies of influential single factors and orthogonal design test , the optimal synthesis conditions of the target product N-(6– amino hexyl) -1,6 - hexanediamine penta methylene phosphonic acid was determined as: the molar ratio of (N-(6– Amino hexyl) -1,6 - hexanediamine, phosphorous acid and formaldehyde solution is 1:5.0:5.5, dropping time is 1.5h, the reaction temperature is 115℃, reaction time is 2.0 h. The active matter content of the target product had been determined by anti- sodium hydroxide titration, the active matter content is high at approximately 48.65%.2) N-(6– amino hexyl) -1,6– hexanediamine penta methylene phosphonic acid has excellent effects on inhibiting scale calcium carbonate and calcium sulfate scale, furthermore, much better than other similar organic phosphonates inhibitors. The scale inhibition efficiency of the monomer were 86.53% and 98.51 %, and the scale inhibition efficiency of the mixture were 89.43% and 99.73%.3) Compared with the current commonly used organic acid phosphatase inhibitor such as amino trimethylene phosphonic acid (ATMP) and diethylene triamine penta methylene phosphonic acid(DTPMP), view from the formula, N-(6– amino hexyl) -1,6– hexanediamine penta methylene phosphonic acid has relatively low phosphorus, only is 22.63%. Visibly, in the same conditions of the water quality and adding concentration, the prosphor content is the lowst in water samples which using the target product, environment friendly, at the same time, the results of scaling inhibition test showed that the scale inhibition efficiency of target product is higher than other products. So N-(6– amino hexyl) -1,6 - hexanediamine penta methylene phosphonic acid is a low phosphorus, highly efficient and environment-friendly organic acid scale inhibitor.4) The results of corrosion performance test showed that: When the concentration of monomer is 20 mg / L, the rate of corrosion is 0.0714 mm / a, the corrosion inhibiting rate is 80%; when the concentration of it is 30 mg / L, the rate of corrosion is 0.0542 mm / a, the corrosion inhibiting rate is 84.8%, When the concentration of it is 20 mg / L, the rate of corrosion is 0.0714 mm / a, the corrosion inhibiting rate is 80%; when the concentration of it is 30 mg / L, the rate of corrosion is 0.0542 mm / a, the corrosion inhibiting rate is 84.8%, the corrosion rate of carbon steels were satisfied for provisions in national relevant specifications, and lower than 0.075 mm / a. and When the concentration of it is 30 mg / L, the increase of the corrosion inhibiting rate is less obvious.In the same time, in the same conditions of the water quality and adding concentration, compared with the ATMP and DETPMP, the performance of N-(6– amino hexyl) -1,6 - hexanediamine penta methylene phosphonic acid is better than ATMP and EDTMP, When the concentration of it is 40 mg / L, the corrosion inhibiting rate of target product is 86.9%, however, the corrosion inhibiting rate of ATMP and DTPMP are 50.3%和 65.8%.
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