Table of contentsIntroductionReactive extraction modelExperimentalResults and discussionNicotinic acid (NA) is a water-soluble B complex vitamin; have antipallegral, antidiarrheal and antidepressant activity. It is a new substance active against cancer and diabetes, a fatal disease. It is an important compound used significantly in the food, pharmaceutical and biochemical industries. The NA recovery study is investigated using tri-n-octylamine (TOA) in a mixture of dodecane and dodecanol in a 1:1 (w/w) ratio. The toxicity study of n-dodecane (log Pa = 6.6) reveals that it is the diluent most suitable for the simultaneous extraction of products during fermentation. However, 1-dodecanol (log Pa = 5.0) can also be used, which provides a very low level of phase toxicity with very high salvation power for extraction and mixing of a non-toxic diluent (dodecane) with a less toxic diluent (decanol) in a 1:1 ratio. (w/w) give a biocompatible diluent with good extraction efficiency. The NA equilibrium study (0.014-0.083 mol.kg-1) is carried out by varying different parameters such as the effect of TOA concentrations (0.148 – 1.201 mol.kg-1), the effect of initial pH of the aqueous solution (2.5-6) ​​and the effect. temperature (298-328 K). Using the equilibrium data, the distribution coefficient (KD), extraction efficiency (%E), and loading rate (z) are calculated. A maximum KD is obtained at 10.8 using optimal TOA (0.706 mol.kg-1) and acid concentration (0.055 mol.kg-1) with 91.53% recovery of NA. Maximum extraction is observed near pH 3.3. It has negligible influence on the 1:1 NA-TOA complex based on model values ​​and FT-IR spectra. The thermodynamic parameters, enthalpy (ΔH0) and entropy (ΔS0) are determined in the temperature range from 298 to 318K. The theoretical number of steps (NTS) for countercurrent extraction under optimal conditions is found to be 4. Additionally, the re-extraction rate was found to be achieved 99.0% using 0.05 mole kg−1 of NaOH as a stripping agent. plagiarism. Get a tailor-made essay on “Why violent video games should not be banned”?Get the original essayKeywords: Nicotinic acid, reactive extraction, tri-n-octylamine, balance, pH, temperature, column design.IntroductionNiacin or nicotinic acid (pyridine -3-carboxylic) is a water-soluble B complex vitamin, which participates in the formation of the coenzymes NAD and NADP. These coenzymes are involved in the catabolism of carbohydrates, fats and proteins with energy production, as well as in the synthesis of fatty acids and cholesterol 1-3. Nicotinic acid is widely used in food, pharmaceutical and biochemical industries. The acid plays a key role in DNA repair and contributes to the formation of steroid hormones in the adrenal gland. Nicotinic acid deficiency can lead to pellagra, red tongue, diarrhea, apathy, depression, disorientation and even memory loss 4, 5. Nicotinic acid also plays a key role in the causes and treatment of other diseases, such as cancer 6, 7, diabetes. 8, 9 and cardiovascular diseases associated with high cholesterol levels 10, 11. As the human body is unable to produce nicotinic acid itself, therefore to maintain its ideal concentration in the body, it must be taken in the form foods such as eggs. , fish and green leafy vegetables or nutritional supplements. However, the overall production of nicotinic acid worldwide has reached approximately 22,000 tonnes/year 12, 13, andeven more emphasis is placed on increasing its production rate. Nowadays, complex chemical synthesis methods are becoming unattractive, due to global awareness. towards growing ecological problems. Thus, the production of nicotinic acid is intensified by biosynthetic or enzymatic conversion of 3-cyanopyridine. The successful production of nicotinic acid (Lonza, Switzerland, China) on a commercial scale using the nitrilase enzyme has proven its industrial application 14, 15-17. In nature, it is widely present in bacteria, filamentous fungi and plants 18, 19. However, downstream processing of bioproducts costs approximately 60% of the total production cost20. Therefore, for large-scale production, it is not preferred over the chemical synthesis route. Thus, another effective method is required for its recovery from diluted fermentation broth via biosynthetic pathway 21. Reactive extraction is one of the effective alternatives to continuously remove valuable organic acids/biological compounds from an aqueous medium, using a suitable extraction system/organic diluents 22. - 24. The toxicity of diluents in the bioreactor is the major concern when the in situ technique is used in separation. Molecular toxicity due to solvent dissolution generally causes less damage to the cell than phase toxicity, because the former is limited by the solubility of the solvent in the aqueous phase. The best possible way to reduce the toxicity of the extraction medium is to mix a non-toxic diluent (log Pa ≥6) with a less toxic diluent (6 ≥ log Pa ≥4)25,26. Previously, several researches on equilibrium and kinetic studies of nicotinic acid are carried out by different researchers. However, no recent literature on the design of nicotinic acid columns using a mixture of biocompatible diluents has been carried out. Earlier, Kumar and Babu 27 review the various manufacturing processes of nicotinic acid. It includes both chemical and enzymatic method. They discovered that the separation of nicotinic acid by reactive enzymatic extraction is a promising technique in terms of improving nicotinic acid production. Sushil and coworkers 28 reported an equilibrium study of nicotinic acid using organophosphate extractant, TOPO and TBP dissolving in different inert and active diluents like n-heptane, n-decane, kerosene, 1 -octanol, 1-decanol, MIBK, etc. Maximum extraction yield is obtained by dissolving TOPO in MIBK. They found that the reaction mechanism is controlled by the type of extractant and the polarity of the solvent. However, pure solvents without extractant are not capable of extracting nicotinic acid effectively. Depaloy et al. investigate the equilibrium and kinetic study of nicotinic acid using TOA in MIBK 29. The equilibrium results show the formation of 1:1 and 2:1 acid-amine complexes. The kinetic study shows that the stirring speed has no effect, however the extraction rate increases with the increase in the volume ratio of the phases. This group also performed an equilibrium study of benzoic acid and nicotinic acid using TOA and TBP dissolved in 30 different binary mixtures. The results suggest that extraction is highly dependent on polarity and ionizing force of the acid. Deliang et al. study the reactive extraction of nicotinic acid with TOA in n-octanol 31. Proton donor n-octanol is found to be an effective diluent when trialkylamine (N235) is used to extract nicotinic acid . Favorable operating conditions are an aqueous pH atthe balance between 4.2 and 5.5. The present paper reports the determination of a suitable column and its design for the optimization of industrial-scale recovery of nicotinic acid from a dilute aqueous broth/fermentation. This is based on the experimental determination of equilibrium data by varying different parameters. Nicotinic acid is recovered by a reactive extraction method using Tri-n-octylamine (TOA) as extractant dissolved in lauryl alcohol (log Pa = 5.032) + dodecane (log Pa = 6.633) in a 1:1 ratio (w/w) throughout the experiments. . However, the combined use of a diluent with a polar modifier also positively affects the extraction yield. However, with the increase in the number of carbon chains, the toxicity of alcohol and alkanes decreases. Therefore, the combination of dodecane and lauryl alcohol as a diluent system will create a non-toxic, biocompatible and environmentally friendly organic phase with good extraction efficiency. Finally, solvent regeneration is carried out using different concentrations of NaOH solution (stripping agent). Reactive extraction modelThe solvent dodecane + lauryl alcohol and the extractant (tri-n-octylamine) used in this study are poorly soluble in water. The solubility of alkane and alcohol decreases with increasing number of carbon chains. Therefore, no volume changes in the aqueous phase and the extract phase are taken into account and all calculations are carried out assuming negligible solubility of the solvents in the aqueous phase. In addition, the solvent or the organic phase co-extracts water in negligible quantities 34, 35. Case I: n = 1 The separation of nicotinic acid from the fermentation broth with TOA dissolved in a mixture of dodecane and d lauryl alcohol (1:1 w/w) has been demonstrated. in eq. (1), assuming that m acid molecule reacts with a TOA molecule (T), with the corresponding equilibrium constant (KE).Experimental materials. Nicotinic acid (SRL Pvt. Ltd, Mumbai, India), tri-n-octylamine (Spectrochem, Mumbai, India), lauryl alcohol (Alfa Aesar), dodecane (Spectrochem, Mumbai, India) were used without any pretreatment. All aqueous phases were prepared using Millipore water (Milli -Q Advance A 10 TOC, Flix, Bangalore). The pH of the aqueous solution is maintained using a reagent grade solution of NaOH and H2SO4. The physiological properties of the chemicals used in the experimental study are presented in Table 1. Table 1. Physical characterization of the reagents used in the experimental study. Reagents Name IUPAC supplier Purity (% weight) Mol. weight (kg.kmol-1) MP(K ) Density (kg.m-3) Viscosity (mPa.s) Dipolar moment (D) Dielectric constantNicotinic acid Pyridine-3-carboxylic acidSRL Pvt. Ltd. 99 123.11 509.6 1470 - 0.219 -Tri-n-octylamine N,N, dioctyl octan-1-amine Spectrochem, Mumbai, (India)95 353.67 134 809 8.32 (296 K) - -Alcohol lauryl 1-Dodecanol Alfa Aesar 98 186.33 299 830 18.8(293 K)1.60 6.50n-dodecane dodecane Spectrochem, Mumbai, (India) 99 170.34 263 750 1.40(293 K) 0 2Equilibrium . The NA stock solution is prepared by adding weighed nicotinic acid to Millipore water. Different concentrations, 0.0136, 0.0341, 0.0548 and 0.0825 mol.kg-1 of nicotinic acid were prepared by diluting the stock solution. The organic phase is prepared by dissolving different concentrations of tri-n-octylamine (TOA) in a mixture (1:1 w/w) of n-dodecanol plus dodecane. The equilibrium extraction experiments were carried out on a constant temperature water bath shaker (Daihan Labtech co. Ltd) for 6 h at 120 ± 5 rpm in 100 ml Erlenmeyer flasks with plastic screw cap. taking equal volumes (20 ml) of aqueous phases and-1).