Pub Date : 2021-01-01DOI: 10.17159/0379-4350/2021/v75a15
D. Karaağaç
ABSTRACT New cyano bridged transition metal complexes, [Cu(detu)4Ni(CN)4]-2H2O (1) and [Zn(H2O)(detu)Ni(CN)4]-2H2O (2) (detu = N, N' diethyl thiourea) have been synthesised in powder form. Their structures were illuminated by using spectroscopic, thermal and elemental analysis techniques. The nickel atom exhibits square planar geometry in these complexes by coordinating with the cyano group's nitrogen atoms. The copper atom of 1 is six coordinated with two bridging cyano groups and four detu ligands. In contrast, the zinc atom of 2 is six coordinated with four bridging cyano groups, one detu ligand and one aqua ligand. In addition, the structure of 2 is formed from polymeric layers of |Zn-Ni(CN)41 „ with the detu and aqua ligands bonded to the zinc atom. Thermal stabilities and decomposition products of 1 and 2 were examined in the static air atmosphere between 30 and 900 °C. Keywords: btetracyanonickelate(II) complex, N,N'-diethyl thiourea, cyano-bridged complex, vibration spectra, thermal analysis.
合成了新型氰基桥接过渡金属配合物[Cu(detu)4Ni(CN)4]-2H2O(1)和[Zn(H2O)(detu)Ni(CN)4]-2H2O (2) (detu = N, N'二乙基硫脲)。利用光谱、热分析和元素分析技术对其结构进行了分析。在这些配合物中，镍原子通过与氰基的氮原子配位而呈现出正方形的平面几何形状。1的铜原子为6，与两个桥接氰基和四个二配体配位。相反，2的锌原子为6，与4个桥接氰基、1个二配体和1个水配体配位。此外，2的结构是由|Zn-Ni(CN)41”的聚合物层形成的，其配体与锌原子键合。1和2的热稳定性和分解产物在30至900°C的静态空气气氛中进行了测试。关键词:二氰酸盐配合物，N,N'-二乙基硫脲，氰桥配合物，振动谱，热分析
{"title":"Preparation and Characterisation of the Cyano-Bridged Transition Metal Complexes Using N,N-Diethyl Thiourea as a Ligand","authors":"D. Karaağaç","doi":"10.17159/0379-4350/2021/v75a15","DOIUrl":"https://doi.org/10.17159/0379-4350/2021/v75a15","url":null,"abstract":"ABSTRACT New cyano bridged transition metal complexes, [Cu(detu)4Ni(CN)4]-2H2O (1) and [Zn(H2O)(detu)Ni(CN)4]-2H2O (2) (detu = N, N' diethyl thiourea) have been synthesised in powder form. Their structures were illuminated by using spectroscopic, thermal and elemental analysis techniques. The nickel atom exhibits square planar geometry in these complexes by coordinating with the cyano group's nitrogen atoms. The copper atom of 1 is six coordinated with two bridging cyano groups and four detu ligands. In contrast, the zinc atom of 2 is six coordinated with four bridging cyano groups, one detu ligand and one aqua ligand. In addition, the structure of 2 is formed from polymeric layers of |Zn-Ni(CN)41 „ with the detu and aqua ligands bonded to the zinc atom. Thermal stabilities and decomposition products of 1 and 2 were examined in the static air atmosphere between 30 and 900 °C. Keywords: btetracyanonickelate(II) complex, N,N'-diethyl thiourea, cyano-bridged complex, vibration spectra, thermal analysis.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67463622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17159/0379-4350/2021/v74a6
Cecil H. Botchway, R. Tia, E. Adei, N. Dzade, N. D. de Leeuw
ABSTRACT Methanol adsorption and dehydration reactions within zeolites represent important steps in the catalytic conversion process to form long-chain hydrocarbons. Herein, first-principles density functional theory (DFT) is employed in the determination of methanol adsorption and conversion in ferrierite (FER), where we predict the fundamental adsorption geometries and energetics of methanol adsorption. The methanol molecule is shown to physisorb at all explored binding sites, stabilized through hydrogen-bonded interactions with the acid site atOmeth-Hframbond distances ranging from 1.33-1.51 A. We demonstrate that the zeolites' adsorption capability is affected by the silicon/aluminium ratio, with stronger adsorptions predicted in the material with silicon to aluminium fractions of 5 than 8. The adsorption strength is also found to vary depending on the tetrahedral binding site, with the T1O2 site yielding the most stable methanol adsorption structure in the Si/Al ratio = 5(Eads = -22.5 kcal mol-1), whereas the T1O1 site yields the most stable adsorption geometry (Eads = -19.2 kcal mol-1) in the Si/Al ratio = 8. Upon translational and rotational motion, methanol is protonated resulting in the breaking of its C-O bond to form a methoxy species bound to the framework oxygen (O-CH3 distance of 1.37 A), whereas the water molecule is stabilized at the acid site through H-bonding (Owat-H = 2.0 A). Further reaction between the methoxy species and a second methanol molecule results in the formation of ethanol and protonated dimethyl ether, with adsorption energies of -42 and -25 kcal mol-1, respectively. The results in this study provide atomistic insight into the effect of acidity of the FER zeolite on the adsorption and conversion of methanol. Keywords: Zeolites, ferrierite, methanol adsorption, acid sites, density functional theory (DFT).
{"title":"H-FER-Catalyzed Conversion of Methanol to Ethanol and Dimethyl Ether: a First-Principles DFT Study","authors":"Cecil H. Botchway, R. Tia, E. Adei, N. Dzade, N. D. de Leeuw","doi":"10.17159/0379-4350/2021/v74a6","DOIUrl":"https://doi.org/10.17159/0379-4350/2021/v74a6","url":null,"abstract":"ABSTRACT Methanol adsorption and dehydration reactions within zeolites represent important steps in the catalytic conversion process to form long-chain hydrocarbons. Herein, first-principles density functional theory (DFT) is employed in the determination of methanol adsorption and conversion in ferrierite (FER), where we predict the fundamental adsorption geometries and energetics of methanol adsorption. The methanol molecule is shown to physisorb at all explored binding sites, stabilized through hydrogen-bonded interactions with the acid site atOmeth-Hframbond distances ranging from 1.33-1.51 A. We demonstrate that the zeolites' adsorption capability is affected by the silicon/aluminium ratio, with stronger adsorptions predicted in the material with silicon to aluminium fractions of 5 than 8. The adsorption strength is also found to vary depending on the tetrahedral binding site, with the T1O2 site yielding the most stable methanol adsorption structure in the Si/Al ratio = 5(Eads = -22.5 kcal mol-1), whereas the T1O1 site yields the most stable adsorption geometry (Eads = -19.2 kcal mol-1) in the Si/Al ratio = 8. Upon translational and rotational motion, methanol is protonated resulting in the breaking of its C-O bond to form a methoxy species bound to the framework oxygen (O-CH3 distance of 1.37 A), whereas the water molecule is stabilized at the acid site through H-bonding (Owat-H = 2.0 A). Further reaction between the methoxy species and a second methanol molecule results in the formation of ethanol and protonated dimethyl ether, with adsorption energies of -42 and -25 kcal mol-1, respectively. The results in this study provide atomistic insight into the effect of acidity of the FER zeolite on the adsorption and conversion of methanol. Keywords: Zeolites, ferrierite, methanol adsorption, acid sites, density functional theory (DFT).","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67463743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17159/0379-4350/2021/v75a17
P. Myburgh, G. Kemp, P. Forbes
ABSTRACT A molecularly imprinted solid-phase extraction (MISPE) procedure was developed for the GC-MS analysis of four high priority pesticides (atrazine, terbuthylazine, acetochlor and alachlor) in a cannabis bud sample matrix. The study demonstrated that the synthesised polymer had a high affinity and good selectivity for either chloroacetamide or triazine classes of pesticide used as a template molecule during the molecularly imprinted polymerisation reaction. The MISPE procedure was optimised in terms of loading, washing and elution fractions utilising a range of aqueous methanol solutions for optimal recovery and minimal matrix interferences. The optimal wash fraction was 20% (v/v) methanol in an aqueous solution, whilst 70% (v/v) was used for the elution fraction. The selectivity, accuracy and recovery of the MISPEs were verified using a synthesised non-imprinted polymer and a commercial C18 cartridge as reference sorbents in comparative experiments. Approximately 3 g of the cannabis bud sample was spiked at a 0.05 mg/kg maximum residue limit (MRL) concentration. The recovery of the four selected pesticides extracted from the spiked samples ranged between 76.4-85.0% when utilising the optimised MISPE methods, compared to 91.6-96.9% for the C18 SPE. However, the use of the MISPE resulted in enhanced selectivity, as evidenced by GC-MS analysis, due to the extraction of less matrix interferences. Therefore, it can be concluded that the MISPE is a viable pre-treatment method for selective pesticide analysis in cannabis flowers using GC-MS when selectivity is valued for the extraction of target pesticides from a complex sample matrix. Keywords: molecularly imprinted polymer; solid-phase extraction; Cannabis; pesticides; atrazine; terbuthylazine; acetochlor; alachlor
{"title":"Selective Solid-Phase Extraction Using Molecularly Imprinted Polymers for the Analysis of Target Pesticides in Cannabis Bud","authors":"P. Myburgh, G. Kemp, P. Forbes","doi":"10.17159/0379-4350/2021/v75a17","DOIUrl":"https://doi.org/10.17159/0379-4350/2021/v75a17","url":null,"abstract":"ABSTRACT A molecularly imprinted solid-phase extraction (MISPE) procedure was developed for the GC-MS analysis of four high priority pesticides (atrazine, terbuthylazine, acetochlor and alachlor) in a cannabis bud sample matrix. The study demonstrated that the synthesised polymer had a high affinity and good selectivity for either chloroacetamide or triazine classes of pesticide used as a template molecule during the molecularly imprinted polymerisation reaction. The MISPE procedure was optimised in terms of loading, washing and elution fractions utilising a range of aqueous methanol solutions for optimal recovery and minimal matrix interferences. The optimal wash fraction was 20% (v/v) methanol in an aqueous solution, whilst 70% (v/v) was used for the elution fraction. The selectivity, accuracy and recovery of the MISPEs were verified using a synthesised non-imprinted polymer and a commercial C18 cartridge as reference sorbents in comparative experiments. Approximately 3 g of the cannabis bud sample was spiked at a 0.05 mg/kg maximum residue limit (MRL) concentration. The recovery of the four selected pesticides extracted from the spiked samples ranged between 76.4-85.0% when utilising the optimised MISPE methods, compared to 91.6-96.9% for the C18 SPE. However, the use of the MISPE resulted in enhanced selectivity, as evidenced by GC-MS analysis, due to the extraction of less matrix interferences. Therefore, it can be concluded that the MISPE is a viable pre-treatment method for selective pesticide analysis in cannabis flowers using GC-MS when selectivity is valued for the extraction of target pesticides from a complex sample matrix. Keywords: molecularly imprinted polymer; solid-phase extraction; Cannabis; pesticides; atrazine; terbuthylazine; acetochlor; alachlor","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67463690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17159/0379-4350/2021/v75a18
F. Belhadj, Z. Kibou, M. Benabdallah, M. Aissaoui, M. Rahmoun, D. Villemin, N. Choukchou-Braham
ABSTRACT A simple and efficient approach has been developed to synthesise novel and functionalised 5H-chromeno[2,3-d] pyrimidines derivatives (4a-h). This approach entails treating 2-amino-3-cyano-4H-chromenes (3a-h) with formamidine acetate under microwave irradiations and solvent-free conditions. All structures of new compounds obtained in this study were characterised by IR, MS, 1H and 13C NMR analysis. Additionally, the synthesised compounds were investigated for their antibacterial and antioxidant potential. Compounds 3b, 3c, 3e, 4c and 4e showed significant activities. Keywords: 5H-chromeno[2,3-d] pyrimidine; 4H-chromene; solvent-free conditions; antioxidant activity; antibacterial activity
{"title":"Synthesis and Biological Evaluation of New Chromenes and Chromeno[2,3-d] pyrimidines","authors":"F. Belhadj, Z. Kibou, M. Benabdallah, M. Aissaoui, M. Rahmoun, D. Villemin, N. Choukchou-Braham","doi":"10.17159/0379-4350/2021/v75a18","DOIUrl":"https://doi.org/10.17159/0379-4350/2021/v75a18","url":null,"abstract":"ABSTRACT A simple and efficient approach has been developed to synthesise novel and functionalised 5H-chromeno[2,3-d] pyrimidines derivatives (4a-h). This approach entails treating 2-amino-3-cyano-4H-chromenes (3a-h) with formamidine acetate under microwave irradiations and solvent-free conditions. All structures of new compounds obtained in this study were characterised by IR, MS, 1H and 13C NMR analysis. Additionally, the synthesised compounds were investigated for their antibacterial and antioxidant potential. Compounds 3b, 3c, 3e, 4c and 4e showed significant activities. Keywords: 5H-chromeno[2,3-d] pyrimidine; 4H-chromene; solvent-free conditions; antioxidant activity; antibacterial activity","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"43 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67463870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17159/0379-4350/2021/V75A10
Vashen Moodley, S. Maddila, S. Jonnalagadda, W. E. Zyl
ABSTRACT Water pollution by organic pollutants is a continuous and increasing problem of global concern. In this paper, we developed a nanocrystalline cellulose (NCC) and titania (TiO2) based nanocomposite for the photocatalytic degradation of o-chloranil via aqueous wet impregnation. Different NCC loadings (10, 20, 40, and 80%) were used, and several analytical and microscopy techniques characterised the NCC/TiO2 catalyst. The efficiency of TiO2 as a photo-catalyst was enhanced through the chiral nematic nature and potential charge carrier capacity of NCC, which lowered the rate of electron recombination. The NCC/TiO2 material was used in the solar-driven photo-degradation of o-chloranil (3,4,5,6-tetrachloro-1,2-benzoquinone), a by-product of a commonly used pesticide. The successful decomposition of o-chloranil led to the successful identification of three breakdown products, namely 2,3-dichloro-4,5-dioxohex-2-enedoic acid (DCA), 2,3-dioxosuccinic acid (DSA) and oxalic acid (OA). The 20% NCC/TiO2 catalyst was found to be optimum and showed excellent degradation and mineralisation of o-chloranil within 2 hours (~90% degradation after 2 hours or 0.00920 mols of the total 0.0102 mols). The degradation products were analysed and identified using GC-MS. The photo-catalyst offers many benefits, including ease of preparation, a low cost-factor, and high stability with no loss of activity. Keywords: nanocrystalline cellulose; o-chloroanil; photocatalyst; photo-degradation; titania
{"title":"Degradation of o-Chloranil Using Nanocrystalline-Cellulose/TiO2 Composites via a Solar Photocatalytic Route","authors":"Vashen Moodley, S. Maddila, S. Jonnalagadda, W. E. Zyl","doi":"10.17159/0379-4350/2021/V75A10","DOIUrl":"https://doi.org/10.17159/0379-4350/2021/V75A10","url":null,"abstract":"ABSTRACT Water pollution by organic pollutants is a continuous and increasing problem of global concern. In this paper, we developed a nanocrystalline cellulose (NCC) and titania (TiO2) based nanocomposite for the photocatalytic degradation of o-chloranil via aqueous wet impregnation. Different NCC loadings (10, 20, 40, and 80%) were used, and several analytical and microscopy techniques characterised the NCC/TiO2 catalyst. The efficiency of TiO2 as a photo-catalyst was enhanced through the chiral nematic nature and potential charge carrier capacity of NCC, which lowered the rate of electron recombination. The NCC/TiO2 material was used in the solar-driven photo-degradation of o-chloranil (3,4,5,6-tetrachloro-1,2-benzoquinone), a by-product of a commonly used pesticide. The successful decomposition of o-chloranil led to the successful identification of three breakdown products, namely 2,3-dichloro-4,5-dioxohex-2-enedoic acid (DCA), 2,3-dioxosuccinic acid (DSA) and oxalic acid (OA). The 20% NCC/TiO2 catalyst was found to be optimum and showed excellent degradation and mineralisation of o-chloranil within 2 hours (~90% degradation after 2 hours or 0.00920 mols of the total 0.0102 mols). The degradation products were analysed and identified using GC-MS. The photo-catalyst offers many benefits, including ease of preparation, a low cost-factor, and high stability with no loss of activity. Keywords: nanocrystalline cellulose; o-chloroanil; photocatalyst; photo-degradation; titania","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"13 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67463931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-01DOI: 10.17159/0379-4350/2021/V75A14
M. Kelani, D. Dieudonné, Kornelia J. Skowron, Clayton A. Pedigo, Thavenden Govender, H. Kruger, Tricia Naicker, Oluseye K. Onajole
ABSTRACT Advances in Nuclear Magnetic Resonance (NMR) spectroscopy is a cornerstone in structure elucidation of polycyclic 'cage' scaffolds. Due to the compactness of these compounds, much overlap, as well as unique through-space and bond NMR interactions are frequently observed. This review serves as a guide for the NMR elucidation of future derivatives by providing some of the typical and relevant aspects of the characteristic trends, substituent patterns and chemical shift behaviour for the identification of the polycyclic structures, namely adamantane, pentacycloundecane and trishomocubane derivatives. Keywords: adamantane, NMR elucidation, pentacycloundecane, polycyclic compounds, trishomocubane
{"title":"Trends in NMR Structural Elucidation Of Polycyclic Cages, Namely: Adamantane, Pentacycloundecane and Trishomocubane","authors":"M. Kelani, D. Dieudonné, Kornelia J. Skowron, Clayton A. Pedigo, Thavenden Govender, H. Kruger, Tricia Naicker, Oluseye K. Onajole","doi":"10.17159/0379-4350/2021/V75A14","DOIUrl":"https://doi.org/10.17159/0379-4350/2021/V75A14","url":null,"abstract":"ABSTRACT Advances in Nuclear Magnetic Resonance (NMR) spectroscopy is a cornerstone in structure elucidation of polycyclic 'cage' scaffolds. Due to the compactness of these compounds, much overlap, as well as unique through-space and bond NMR interactions are frequently observed. This review serves as a guide for the NMR elucidation of future derivatives by providing some of the typical and relevant aspects of the characteristic trends, substituent patterns and chemical shift behaviour for the identification of the polycyclic structures, namely adamantane, pentacycloundecane and trishomocubane derivatives. Keywords: adamantane, NMR elucidation, pentacycloundecane, polycyclic compounds, trishomocubane","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17159/0379-4350/2020/v73a8
C. Ikese, S. T. Ubwa, S. Adoga, S. Audu, M. I. Kuleve, F. O. Okita, A. Okoh
The bioactive ingredients in most malarial drugs only reduce plasmodium load during chemotherapy. No anti-malarial drug replenishes the red blood cells destroyed by Plasmodium. This creates a need to incorporate bioactive components with haematinic property in malaria therapy. This study aimed to assess the effect of T. occidentalis leaf extract on packed cell volume (PCV) of rats with malaria-induced anaemia. Anaemia was induced in the rats by inoculating them with Plasmodium berghei. The effect of the plant extract on the PCV of the rats was determined alongside a negative and a positive control. Also, the effect of varying doses of the extract on PCV of the rats was determined. T. occidentalis leaf extract produced a 22 % increase in the post-inoculation PCV of rats. The negative and positive control groups showed a 37 % and 25 % decrease, respectively, in PCV. Also, PCV increased with increase in extract dose administered.
{"title":"Effect of Telfaira occidentalis Leaf Extract on Packed Cell Volume in Rats with Malaria-induced Anaemia","authors":"C. Ikese, S. T. Ubwa, S. Adoga, S. Audu, M. I. Kuleve, F. O. Okita, A. Okoh","doi":"10.17159/0379-4350/2020/v73a8","DOIUrl":"https://doi.org/10.17159/0379-4350/2020/v73a8","url":null,"abstract":"The bioactive ingredients in most malarial drugs only reduce plasmodium load during chemotherapy. No anti-malarial drug replenishes the red blood cells destroyed by Plasmodium. This creates a need to incorporate bioactive components with haematinic property in malaria therapy. This study aimed to assess the effect of T. occidentalis leaf extract on packed cell volume (PCV) of rats with malaria-induced anaemia. Anaemia was induced in the rats by inoculating them with Plasmodium berghei. The effect of the plant extract on the PCV of the rats was determined alongside a negative and a positive control. Also, the effect of varying doses of the extract on PCV of the rats was determined. T. occidentalis leaf extract produced a 22 % increase in the post-inoculation PCV of rats. The negative and positive control groups showed a 37 % and 25 % decrease, respectively, in PCV. Also, PCV increased with increase in extract dose administered.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"73 1","pages":"51-54"},"PeriodicalIF":1.5,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17159/0379-4350/2020/v73a9
A. Mohammadzadeh, A. P. Marjani, A. Zamani
In the present study, we have designed and synthesized a new magnetically recoverable, nanocatalyst of Ag/Fe3O4@starch. The successful synthesis and the structure of the nanocatalyst were confirmed and evaluated with several analytical techniques including XRD, EDX, VSM, FT-IR, TEM and TGA. The impact and efficiency of Ag/Fe3O4@starch were successfully investigated in the one-pot synthesis of desired 4H-pyrans and tetrahydro-4H-chromenes using three-component condensation of various aldehydes, malononitrile, and 1,3-diketoesters or cyclic 1,3-diketones. The magnetic nanocatalyst was easily recovered and reused with high catalytic activity even after up to five runs.
{"title":"A Novel Biopolymer-based Nanomagnetic Catalyst for the Synthesis of 4H-pyran and Tetrahydro-4H-chromene Derivatives","authors":"A. Mohammadzadeh, A. P. Marjani, A. Zamani","doi":"10.17159/0379-4350/2020/v73a9","DOIUrl":"https://doi.org/10.17159/0379-4350/2020/v73a9","url":null,"abstract":"In the present study, we have designed and synthesized a new magnetically recoverable, nanocatalyst of Ag/Fe3O4@starch. The successful synthesis and the structure of the nanocatalyst were confirmed and evaluated with several analytical techniques including XRD, EDX, VSM, FT-IR, TEM and TGA. The impact and efficiency of Ag/Fe3O4@starch were successfully investigated in the one-pot synthesis of desired 4H-pyrans and tetrahydro-4H-chromenes using three-component condensation of various aldehydes, malononitrile, and 1,3-diketoesters or cyclic 1,3-diketones. The magnetic nanocatalyst was easily recovered and reused with high catalytic activity even after up to five runs.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"73 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67464071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17159/0379-4350/2020/v73a14
Cramwell Badla, F. Wewers
An XRF spectrometer traditionally requires its methods to be calibrated using certified reference materials (CRMs). This means choosing from a limited selection of CRMs, which are costly and not widely available. This article examines the application of synthetic oxide standards made from commercially available high purity compounds for the calibration of an XRF spectrometer. Enabling it to analyze for major, minor and trace elements (Mg, Al, Si, P, Hf, Ca, Ti, Zr, Fe, Th, U) in heavy mineral sands processing. Calibration standards were synthesized by mixing pure compounds and mineral sands reference materials, to mimic matrices similar to that of the routine samples and cover the required analytical range. The aliquots were mixed in % fractions and fused with a 1:9 sample/borate dilution to make glass beads. The optimized calibration was validated as per SANAS TR 26-02 criteria for linearity, working range, limit of detection (LOD) and quantification (LOQ), precision and accuracy. The correlation coefficients (r) of the resulting calibration curves were >0.999, showing excellent linearity. The working range for all the calibration lines was satisfactory. The LOD and LOQ values for all the lines were low enough to prevent extrapolation below the lowest calibration point. The precision of the calibration was sufficiently high, and the accuracy was of adequate quality with z(MAD) <2. These observations support the successful synthesis and use of a well-selected set of synthetic standards. Additionally, it has been successfully utilized to analyze a variety of heavy mineral sands samples.
{"title":"Optimization of X-ray Fluorescence Calibration through the Introduction of Synthetic Standards for the Determination of Mineral Sands Oxides","authors":"Cramwell Badla, F. Wewers","doi":"10.17159/0379-4350/2020/v73a14","DOIUrl":"https://doi.org/10.17159/0379-4350/2020/v73a14","url":null,"abstract":"An XRF spectrometer traditionally requires its methods to be calibrated using certified reference materials (CRMs). This means choosing from a limited selection of CRMs, which are costly and not widely available. This article examines the application of synthetic oxide standards made from commercially available high purity compounds for the calibration of an XRF spectrometer. Enabling it to analyze for major, minor and trace elements (Mg, Al, Si, P, Hf, Ca, Ti, Zr, Fe, Th, U) in heavy mineral sands processing. Calibration standards were synthesized by mixing pure compounds and mineral sands reference materials, to mimic matrices similar to that of the routine samples and cover the required analytical range. The aliquots were mixed in % fractions and fused with a 1:9 sample/borate dilution to make glass beads. The optimized calibration was validated as per SANAS TR 26-02 criteria for linearity, working range, limit of detection (LOD) and quantification (LOQ), precision and accuracy. The correlation coefficients (r) of the resulting calibration curves were >0.999, showing excellent linearity. The working range for all the calibration lines was satisfactory. The LOD and LOQ values for all the lines were low enough to prevent extrapolation below the lowest calibration point. The precision of the calibration was sufficiently high, and the accuracy was of adequate quality with z(MAD) <2. These observations support the successful synthesis and use of a well-selected set of synthetic standards. Additionally, it has been successfully utilized to analyze a variety of heavy mineral sands samples.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"73 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67463515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.17159/0379-4350/2020/v73a10
Tebogo M.A. Mokgehie, W. Gitari, N. Tavengwa
Studies were conducted to determine if crystalline zeolites could be obtained from the filtrates of coal fly ash (CFA)/NaOH slurries through sonication. The CFA/NaOH slurries were obtained by aging CFA in 3 M NaOH for 24 h at 50 °C using a solid/ liquid (S/L) ratio of 15 g/120 mL. FT-IR studies indicated that the ‘Lo’ regime ultrasonicated zeolite had higher intensities than that of the ‘Hi’ frequency ultrasonicated zeolite. The bands associated with the ‘Lo’ regime ultrasonicated zeolite were observed at 1066 cm, 1400 cm and 3600 cm, which were identified as Si-O asymmetric stretch, Al-O asymmetric stretch, O-H bend and O-H asymmetric stretch, respectively. Based on PXRD studies, the zeolitic phases were most intense for the 90 min ultrasonicated zeolite. Powder X-ray diffraction studies showed that the phases initially in CFA, such as quartz and aluminosilicate, were converted into gismodine zeolite Na-P1. Morphological changes were seen as ultrasonication period was increased. At short ultrasonication times, irregularly shaped fused-like grain structures were observed, while at longer times separate grain-like structures became more apparent. Energy dispersive X-ray spectroscopy studies on the 90 min ultrasonicated zeolite indicated the presence of Na, O, Si and Al, which were important building-blocks for the zeolites.
{"title":"Synthesis and Characterization of Zeolites Produced by Ultrasonication of Coal Fly Ash/NaOH Slurry Filtrates","authors":"Tebogo M.A. Mokgehie, W. Gitari, N. Tavengwa","doi":"10.17159/0379-4350/2020/v73a10","DOIUrl":"https://doi.org/10.17159/0379-4350/2020/v73a10","url":null,"abstract":"Studies were conducted to determine if crystalline zeolites could be obtained from the filtrates of coal fly ash (CFA)/NaOH slurries through sonication. The CFA/NaOH slurries were obtained by aging CFA in 3 M NaOH for 24 h at 50 °C using a solid/ liquid (S/L) ratio of 15 g/120 mL. FT-IR studies indicated that the ‘Lo’ regime ultrasonicated zeolite had higher intensities than that of the ‘Hi’ frequency ultrasonicated zeolite. The bands associated with the ‘Lo’ regime ultrasonicated zeolite were observed at 1066 cm, 1400 cm and 3600 cm, which were identified as Si-O asymmetric stretch, Al-O asymmetric stretch, O-H bend and O-H asymmetric stretch, respectively. Based on PXRD studies, the zeolitic phases were most intense for the 90 min ultrasonicated zeolite. Powder X-ray diffraction studies showed that the phases initially in CFA, such as quartz and aluminosilicate, were converted into gismodine zeolite Na-P1. Morphological changes were seen as ultrasonication period was increased. At short ultrasonication times, irregularly shaped fused-like grain structures were observed, while at longer times separate grain-like structures became more apparent. Energy dispersive X-ray spectroscopy studies on the 90 min ultrasonicated zeolite indicated the presence of Na, O, Si and Al, which were important building-blocks for the zeolites.","PeriodicalId":49495,"journal":{"name":"South African Journal of Chemistry-Suid-Afrikaanse Tydskrif Vir Chemie","volume":"73 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67463328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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