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Article
Hydrogenation of D-Glucose to D-Mannitol using Raney Nickel Catalyst

Author: Muthanna J. Ahmed
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2009 Volume: 15 Issue: 3 Pages: 3941-3953
Publisher: Baghdad University جامعة بغداد

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Abstract

Hydrogenation of D-glucose in the presence of Raney nickel as a catalyst was employed for the preparation of D-mannitol. The effects of the reaction time (15-115 min), reaction temperature (15-65 oC), and catalyst to D-glucose ratio (3-11 %) on the yield of D-mannitol were studied. The experimental design of Box-Wilson method was adopted to find a useful relationship between the effecting variables and the D-mannitol yield. The experimental data collected by this design was successively fitted to a second order polynomial mathematical model. The analysis of variance shows that the reaction time had the greatest effect on the yield of D-mannitol among other variables. An optimum operating conditions of 115 min reaction time, 50 ˚C reaction temperature, and 3 % catalyst to D-glucose ratio gave 14.01 % D-mannitol yield, 81.34 % D-sorbitol yield, and 94.9 % D-glucose conversion. D-Mannitol of purity 99.7 % was obtained after its separation from D-sorbitol, the second product of the hydrogenation process, using the fractional crystallization method.

يهدف البحث إلى إنتاج المانيتول من الكلوكوز بطريقة الهدرجة و باستعمال (Raney Nickel) كعامل مساعد. تمت دراسة تأثير زمن التفاعل (15- 115 دقيقة), درجة الحرارة (15- 65 ˚م), ونسبة العامل المساعد إلى الكلوكوز (3 - 11 %) على إنتاجية المانيتول. استخدمت طريقة Box-Wilson)) لتكوين علاقة رياضية تربط المتغيرات الثلاثة بإنتاجية المانيتول, وتم تمثيل هذه العلاقة بشكل ناجح بمعادلة من الدرجة الثانية (Second-Order Polynomial) وقد بين التحليل الإحصائي (F-test ) إن زمن التفاعل هو المتغير ذو التأثير الأكبر على إنتاجية المانيتول. إن الظروف التشغيلية المثلى التي أعطت إنتاجية مانيتول عالية هي زمن تفاعل (115دقيقة), درجة حرارة (50˚م), ونسبة عامل مساعد (3%). عند هذه الظروف كانت إنتاجية المانيتول (14,01%), إنتاجية السوربيتول (81,34%), ونسبة تحول الكلوكوز (94,9%). تم استخدام طريقة البلورة التجزيئية لفصل المانيتول من السوربيتول, الذي يعتبر الناتج الثاني لعملية الهدرجة, والحصول على مانيتول بنقاوة (99,7%).


Article
Performance of Corrosion Inhibitors Blend for Simulated Industrial Cooling Waters under Dynamic Conditions

Authors: Abeer A. Al-Khasab --- Qasim J.M.Slaiman
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2015 Volume: 16 Issue: 1 Pages: 1-12
Publisher: Baghdad University جامعة بغداد

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Abstract

The inhibitive action of a blend of sodium nitrite/sodium hexametaphosphate (SN+SHMP) on corrosion of carbon steel in simulated cooling water systems (CWS) has been investigated by weight loss and electrochemical polarization technique. The effect of temperature, velocity, and salts concentrations on corrosion of carbon steel were studied in the absence and presence of mixed inhibiting blend. Also the effect of inhibitors blend concentrations (SN+SHMP), temperatures, and rotational velocity, i.e., Reynolds number (Re) on corrosion rate of carbon steel were investigated using Second-order Rotatable Design (Box-Wilson Design) in performing weight loss and corrosion potential approach. Electrochemical polarization measurements were used to study the behavior of carbon steel in different salts concentrations of (CWS) with pH = 7.5 in absence and presence of the inhibiting blend. The results show that the regression model (Box-Wilson Design) that has been developed using experimental data was used to verify that the interaction term of temperature with inhibitors blend and the square term of inhibitors blend are significant for corrosion rate in 0.05 N NaCl solution while the main variables are not pronounced. Also, it is found that the corrosion rate of carbon steel is increased with increasing temperature, rotational velocity, and NaCl salts concentration in uninhibited and inhibited solutions. Inhibition performance of NaNO2+ Na(PO3)6 was found to increase with its concentration up to 800 ppm inhibitors blend, and the corrosion potential is shifted to more positive direction with increasing rotational velocity, and inhibitor blend concentration.

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