Open Access Original Research Article

Bio Hydrogen Production from Pharmaceutical Waste Water Treatment by a Suspended Growth Reactor Using Environmental Anaerobic Technology

R. Hema Krishna, S. Venkata Mohan, A. V. V. S. Swamy

Chemical Science International Journal, Page 80-97
DOI: 10.9734/ACSJ/2013/2649

Hydrogen (H2) is considered as the future fuel. The present work on “Bio Hydrogen Production from Pharmaceutical Waste Water Treatment by a Suspended Growth Reactor Using Environmental Anaerobic Technology. This is an appreciated approach at wealth generation through value addition to wastes. The optimization process included the selection of ideal co-substrate (sucrose) and nitrogen source (DAP) to examine the feasibility of hydrogen production from industrial effluent in a 50%-50% mixture of the complex feed and the industrial effluent. Hydrogen gas produced in the reactor is estimated using a gas sensor. This equipment is a generic gas-monitoring instrument with microprocessor based electronics interfacing with std. 4 to 20 mA alarm/control systems. The inlet pH (feed) was maintained at 6 while the outlet pH monitored after detention time showed a slight variation (4 to 5.4) throughout the reaction periods .The variation in Volatile fatty acids (VFA) was evident up to 21 day of operation, and thereafter stabilized in and around 2600 mg/l indicating the steady state condition of the reactor. The alkalinity values variation indicated an increase in system response to acidogenic fermentation process. The variation of COD reduction (%) indicates multitude of variations as the experiment proceeds indicating perfect degradation of the organic substrate present in the culture aimed towards hydrogen production.VFA evaluation through High power liquid chromatography (HPLC) indicated presence of acetic acid within the system which could be the possible substrate for hydrogen production. During sequencing phase operation, the hydrogen values given by the experimental run with the effluent as the main substrate showed greater production rate (0.81 mmol/hr)  when compared to that produced in the previous  cases using only synthetic (0.086 mmol/hr) and complex feeds (0.29 mmol/hr ) respectively. The described process has the dual benefit of combined H2 production and wastewater treatment in an economical, effective and sustainable way. 


Open Access Original Research Article

Occupational Safety and Environmental Risks Scenario of Small and Medium Enterprises (SMEs): An Analysis of the Situation in Harare Chemical Industries, Zimbabwe

N. Mudavanhu, P. Dzomba, C. Mudavanhu, S. Mazorodze

Chemical Science International Journal, Page 98-110
DOI: 10.9734/ACSJ/2013/2759

Aims: To analyze the nature and peculiarities of Small and Medium Enterprises (SMEs) in Zimbabwe chemical industry with reference to safety and environmental risks.

Study Design: This study took a survey approach.

Place and Duration of Study: Graniteside (GR), Willowvale (WV), Southerton (ST), Workington (WN) and Msasa (MS) industrial areas in Harare Zimbabwe between June 2011 and October 2012.

Methodology: We administered a survey-questionnaire to collect primary data from respondents coming from 49 SMEs using proportional sampling (7 GR, 10 ST, 12 WN, 11 WV and 9 MS); 6 Large Enterprises (LEs) and 5 key informants from government and industry associations. Other data was obtained from document analysis from libraries and websites of industrial association and observations made on industrial visits.

Results: Results showed that 85.6%, 93.8%, 95.9% and 93.8% of SMEs did not have Occupational Safety and Health (OSH) policies, risk analysis strategy, staff welfare facilities and did not keep accident records respectively. Moreover, most premises were not appropriate for chemical handling; processing and storage due to the fact that the enterprises had shunned government designated areas. The LEs interviewed had comprehensive approach to safety and environmental management, though most of them struggle mainly with risk analysis. Analysis showed that the current SME OHS scenario was due to lack of national legislation governing their operation. This results in SME operations being informal, up to individual organization’s discretion and without regard to OSH and environmental management.

Conclusion: Though SMEs largely contribute to Zimbabwean economy and to output of chemical industry, their operations are out rightly OSH and environmentally irresponsible. The OSH scenario of SMEs could be improved by involvement of all stakeholders in policy formulation and support. Collaboration, information disclosure and benchmarking with long established large enterprises can enhance SMEs OHS and environmental management.


Open Access Original Research Article

Comparative Study of Benzenediols, Methylphenols and Chloroanilines Isomers on the Inhibition of Acetoclastic Methanogenesis By Digested Pig Manure Methanogenic Archaea

K. Kayembe, L. Basosila, K. Mbuyu, P. C. Sikulisimwa, A. C. Kitambala, P. T. Mpiana

Chemical Science International Journal, Page 111-123
DOI: 10.9734/ACSJ/2013/2491

Aims: The present work aims to study the effect of aromatic structure on the inhibition of biogas biosynthesis, and more specifically the comparative study of benzenediols, methylphenols and chloroanilines isomers on the inhibition of acetoclastic methanogenesis by digested pig manure methanogenic archaea. The objective of this study was also to examine the structure-toxicity relationships of aromatic compounds to acetoclastic methanogens. The ultimate goal is the modeling of the influence of the aromatic structure on the inhibition of methane biosynthesis.

Study Design: Anaerobic digestion of pig manure, anaerobic toxicity essay, Effect of the isomerism (functional groups position) on the methanogenic toxicity, Correlation of the methanogenic toxicity  with aromatic compounds hydrophobicity (logPoct),

Place and Duration of Study: Department of Chemistry, University of Kinshasa, DR Congo, between January 2011 and March 2012.

Methodology: The toxicity to acetoclastic methanogenic archaea was performed with the standard method of serum bottles, digested pig manure was utilized as inoculums and acetate as substrate The methane gas volume produced was measured by serum bottles liquid displacement systems (Mariotte flask system).

Results: The obtained results indicate that relationships exist between the isomerism of cresols, benzediols (catechol, resorcinol, and hydroquinone) and chloroanilines; and their inhibitory effects on methanogenic archaea. The toxicity of Cresols, benzenediols and reference compounds increases, respectively, in the following order: Benzenediols < Phenol < Cresols. The grafting of methyl (-CH3) at phenol to form cresols, make cresols to be more toxic than phenol. Secondly, by adding a hydroxyl group (-OH) at phenol to form benzenediols, these compounds become less toxic than phenol. The grafting of chlorine (-Cl) at aniline to form chloroanilines, make chloroanilines to be more toxic than aniline. And secondly, by adding an amino group (-NH2) at chlorobenzene to form chloroanilines, these compounds become less toxic than Chlorobenzene. For the three isomers studied in this work, ortho is the most toxic followed by meta while para is always the less toxic.

A high significant linear correlation between the toxicity of cresol, benzenediols and chloroanilines isomers and reference aromatic compounds and their hydrophobicity (R2 = 0.9278) was found.

Conclusion: The results obtained in this paper indicate that it exist a correlation between the isomerism (chemical structure) of Cresols, benzendiols, chloroanilines and their inhibitory effects on methanogens. Hydrophobicity of a compound as indicated by logPoct is directly related to the partition of a compound into archaeal membrane.


Open Access Original Research Article

Acylation of Grape Leaves Polyprenols

U. T. Zakirova, N. K. Khidyrova, Kh. U. Khodjaniyazov, Kh. M. Shakhidoyatov

Chemical Science International Journal, Page 124-136
DOI: 10.9734/ACSJ/2013/2916

Aims: The study is aimed to obtain acylated derivatives of polyprenols which were isolated from leaves of grape Vitis vinifera L.

Study Design: Modification of natural compounds.

Place and Duration of Study: Department of Organic Chemistry, Institute of the Chemistry of Plant Substances (ICPS). The study was carried out between January, 2011 and December, 2012.

Methodology: Polyprenols were acylated by anhydrides of mono- and dicarboxylic acids in absolute benzene in the presence of catalytic amounts of dry pyridine within 1-2 hours (method A). Polyprenols were acylated also by anhydrides of mono- and dicarboxylic acids in the presence of catalyst (dry pyridine) in absence of solvents at 70-80оС within 1 or 2 hours (method B). For the acylation of polyprenols the microwave method has been used in absence of the solvent and the catalyst (method C). The courses of reactions were controlled by TLC, HPLC, and HPTLC. Structure of acyl-products determined by IR-, 1H NMR and mass-spectra.

Results: In the method A with decreasing of acid’s strength and increasing of molecular weight the yield of acyl-products is decreased. Acylation by benzoyl anhydride yielded to acyl-products between acylation by acetic and propionic anhydrides. Decreasing of yields of acyl-products was observed at usage of anhydrides of dicarboxylic acids. In the method B decreasing of the yields was observed also with decreasing of acid’s strength and increasing of molecular weight of the acylating agent. Thus yields were a bit high (in addition 1-6 %). In the method C (MWA) duration of acylation reaction has sharply contracted (on 20 60 times in comparison with the method A, and 10-30 times in comparison with the method B), i.e. yields of acyl-products are enlarged by 13.5-24.6 % (in comparison with a method A) and 7.5-21.6 % (with a method B) at usage of anhydrides of monocarboxylic acids. At MWA acylation by anhydrides of dicarboxylic acids duration of reaction contracts at 20-40 times in comparison with the method A and 10-30 times in comparison with the method B. The yields are increased on 8.2 - 17.5 % (in comparison with the method A) and 5.2-16.5 % (in comparison with the method B).

Conclusion: Acylation reactions of polyprenols with anhydrides of mono- and dicarboxylic acids, organic acids have been studied in various conditions. Usage MWA allows performing esterifications with high yields (from 59 % to 89.6 % in the case of monocarboxylic acids and from 56.2 to 78 % in the case of dicarboxylic acids). Duration of MWA acylation reaction was 6-10 minutes in the case of polyprenol acylation by monocarboxylic acids, and 12-14 minutes in the case of dicarboxylic acids. Therefore MWA method, undoubtedly, is a cost effective method for the acylation.


Open Access Original Research Article

Theoretical Study of Stability, Tautomerism, Equilibrium Constants (pKT) of 2-Thiouracil in Gas Phase and Different Solvents (Water and Acetonitrile) by the Density Functional Theory Method

N. Surendra Babu

Chemical Science International Journal, Page 137-150
DOI: 10.9734/ACSJ/2013/2905

A density functional theory (DFT) calculations were carried out to investigate the relative energies, equilibrium constants and dipole moments of 2-thiouracil in the gas phase and in solutions with different polarities. Solvent effects were examined by means of the self-consistent reaction field (SCRF) method. All possible tautomers are optimized at the B3LYP/6- 311++G (d,p). All calculations indicate that the most stable tautomer for both species, in the gas phase as well as in solution, has the 2TU1 form.In addition to calculate the thermodynamic properties and the inter conversion equilibrium constants for all tautomers. The molar transfer Gibbs energies of ∆∆Gt0 (solvent1- solvent 2), determines the solvent effect on the position of the equilibrium.


Open Access Original Research Article

Characterization of Plasma Sprayed Pure Red Mud Coatings: An Analysis

Alok Satapathy, Harekrushna Sutar, Subash Chandra Mishra, Santosh Kumar Sahoo

Chemical Science International Journal, Page 151-163
DOI: 10.9734/ACSJ/2013/3218

The characteristics of plasma sprayed pure red mud coatings have been investigated.The red mud was collected as a waste from aluminium production. In order to understand the coating characteristics, pure red mud was plasma coated. After plasma spraying, the coated materials have been subjected to series of tests to determine coating thickness, adhesion strength, micro structural characterization of cross section, X-ray diffraction and coating deposition efficiency. Plasma spraying is done at 200, 250, 300 and 400 ampere current. Torch input power is maintained at 6,9,12 and 16 kW. The coating samples chose are dimension 50mm×25mm×2mm. Available substrates are made of aluminium, copper, mild steel and stainless steel.


Open Access Original Research Article

Thieno[2,3-d ]Pyrimidin-4-Ones. Part 2*. Condensation of 2,3- Disubstituted Thieno[2,3-d]Pyrimidin-4-Ones with Aldehydes

B. Zh. Elmuradov, Kh. A. Bozorov, Kh. M. Shakhidoyatov

Chemical Science International Journal, Page 164-177
DOI: 10.9734/ACSJ/2013/2966

The reactions of 2,3-tri-,-tetramethylene-7,8–dihydro-6Н–thieno[2,3-d]pyrrolo[1,2-a] pyrimidine-4-ones (1a,b) and 2,3-dimethyl-,-tri-,-tetra-,-pentamethylene-6,7,8,9-tetrahydropyrido[1,2-a]thieno[2,3-d]pyrimidine–4-ones (4a-d), containing active methylene groups in positions 8 or 9, with aromatic aldehydes under acidic and alkaline conditions go depending on reaction conditions and nature of aromatic aldehydes with the formation of new (±)-(4-nitrophenyl) (2,3-tri, tetramethylene-7,8-dihydropyrrolo[1,2-a]thieno[2,3-d] pyrimidine-4-one-8-yl) methanol’s (2,3), 9-arylidene derivatives (5a-e – 8a-e) and (±) - (4 - nitrophenyl) (2,3-tetramethylene-6,7,8,9- tetrahydropyrido[1,2-a]thieno[2,3-d]pyrimidine–4–one-9-yl)methanol (9). If aldehydes with electron-withdrawing (nitro) group are used, the reaction can be stopped at a stage where the products of electrophilic addition reactions are racemates, i.e. containing asymmetric carbon atom in position 8 or 9, and if aromatic aldehydes with electron-donating substituent are used 9-arylidene derivatives are formed exclusively.