Application of microwave irradiation for fabrication of sulfated ZrO2–Al2O3 nanocomposite via combustion method for esterification reaction: process condition evaluation

Nayebzadeh, Hamed; Saghatoleslami, Nasser; Tabasizadeh, Mohammad

doi:10.1007/s40097-019-0304-y

Cited by 23 publications

(10 citation statements)

References 48 publications

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“…Despite the efforts of the world scientific community to solve the global problem of processing non-conductive ceramics and nanoceramics due to the inclusion of the secondary phase, the issue remains unresolved [34,37,47,48,50,51,88,102]. The main issue that hampers the advances is related to the material of the secondary phase, which often is not widely available for use in the conditions of real production [33,34,36,37,40,44,89,103].…”

Section: Discussionmentioning

confidence: 99%

“…For example, in the case of processing naturally widely available oxide ceramics such as ZrO 2 and Al 2 O 3 , their melting points are of 2715 • C and 2054 • C, respectively [33,49,50,68]. The introduction of an additional process initiator can result in the physical ablation of the ceramics with the formation of the conductive form ZrC and unstable compound Al 4 C 3 , which can theoretically assist processing.…”

Section: Discussionmentioning

confidence: 99%

“…The analysis of the leading world scientific competitors in this domain shows that the world community is separated as it was mentioned above. One group of scientists is focused on the modification of nanoceramics with conductive inclusions to create systems such as ZrO 2 -Ta, ZrO 2 -TiC, ZrO 2 -TiCN, Si 3 N 4 -TiC, Si 3 N 4 -TiCN, Al 2 O 3 -TiC, Al 2 O 3 -TiCN [49][50][51][52][53][54][55][56][57][58][59], as well as inclusions based on graphene and oxide graphene and graphene nanotubes [23,[60][61][62][63][64]. Another group of scientists has focused their research on the processing capabilities of existed ceramics and non-conductive ceramic composites.…”

Section: The Main Scientific Competitorsmentioning

confidence: 99%

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On Electrical Discharge Machining of Non-Conductive Ceramics: A Review

et al. 2019

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The inability of ceramic and nanoceramic processing without expensive diamond tools and with a high-material-removal rate hampers the scope of its potential applications and does not allow humanity to make a full shift to the sixth technological paradigm associated with Kuhn scientific revolutions and Kondratieff's waves and restrains the growth of the economy. The authors completed a review on the research state of ceramic and nanoceramic processing by electrical discharge machining, which is possibly solved by two principal approaches associated with the usage of standard commercially available machine tools. The first approach is related to the introduction of expensive secondary phase; the second approach proposes initiate processing by adding auxiliary electrodes in the form of coating, suspension, aerosol, or 3D-printed layer based on the components of silver, copper, or graphite in combination with an improved dielectric oil environment by introducing graphite or carbon nanoparticles, which is hugely relevant today.Technologies 2019, 7, 55 2 of 16 of cutting tools limits the resulting geometry of the product. Other machining methods such as vibroacoustic machining, laser and electron beam scribing, selective laser sintering with a binder, find their specific place in the processing of ceramics. However, they do not allow the receiving of all geometrically possible shapes of the product without losses on the operational parameters of ceramics [16][17][18].One of the most popular methods for the production of parts, regardless of their hardness, is electrical discharge machining (EDM). However, it requires the material to be conductive [19][20][21]. The process of electrical erosion of the material consists of initiating electric pulses in the interelectrode gap, in the breakdown of the dielectric medium in the gap, in establishing a discharge channel, where the temperature reaches more than 10,000 • C (low-temperature plasma). Due to such temperatures, the material is ablated, the drops of cooled material as eroded debris are washed away by the flow of the dielectric medium, and the electrodes again approach to resume the cycle. Thus, a unique crater-like topology on the surface of the workpiece is created [22][23][24][25].The inability of ceramics and nanoceramics to conduct current hampers the scope of its potential applications and restrains the growth of the progress and the switch to the next technological paradigm that most of the scientists associate with the term "nano" [26][27][28][29][30][31][32].Thus, it can be concluded that the study and development of a method for electrical discharge machining of non-conductive ceramics and nanoceramics are incredibly relevant today.The authors propose to apply the dialectical approach of cognition as a scientific approach to solve the formulated scientific problem. The dialectical approach includes the systematization and updating of existing knowledge and new data about the object of research.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: The Main Scientific Competitorsmentioning

confidence: 99%

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On Electrical Discharge Machining of Non-Conductive Ceramics: A Review

et al. 2019

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“…Moreover, egression of carbon groups, such as CO 2, may have occurred in this region [57]. In the last region, from 450 to 600 • C, 4% weight loss was detected, due to decomposition of organic (if any) groups and diffusion of Zr/Ca cations into the titania lattice [59]. However, the weight loss in the third section was low, and this confirms a good calcination process in the sample for forming a calcium/titania-zirconia nano-composite.…”

Section: Structural Assessment Of Optimum Catalystmentioning

confidence: 94%

Modelling and Optimisation of the Sol-Gel Conditions for Synthesis of Semi-Hexagonal Titania-Based Nano-Catalyst for Esterification Reaction

et al. 2022

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Design and fabrication of a catalyst with the highest activity can be achieved by optimising the synthesis conditions. In this study, the sol-gel synthesis conditions of citric acid concentration, gelling temperature, complex time, and calcination temperature were studied for the preparation of a novel semi-hexagonal calcium/titania-zirconia nano-catalyst used in the esterification reaction. After synthesis of around 24 samples at various conditions, their activity was tested in the esterification reaction and the results were analysed by multi-layer perceptron (MLP) and support vector machine (SVM) models. Both models predicted the actual data with high coefficients of determination, and indicated that the calcination temperature has the most influence on the activity of the prepared semi-hexagonal calcium/titania-zirconia nano-catalyst for the esterification reaction. Moreover, the genetic algorithm (GA) was utilised for optimising the preparation conditions based on the SVM model, due to its higher generalisation capability for prediction. The prepared nano-catalysts under the optimum conditions of 1.42 acid ratio, gelling temperature of 72 °C, complex time of 2.65 h, and calcination temperature of 487 °C showed good crystalline structure and metal–metal and metal–oxygen cation bonding. Finally, the fabricated catalyst had a high surface area (276.5 m2/g) with 3.5 nm pore diameter and almost uniform particle size (80–110 nm) distribution, leading to a high conversion of 97.6% in the esterification reaction, with good catalytic stability up to five times.

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“…As a result, the heterogeneous catalysts which are highly efficient, ecologically correct, recyclable, and environment‐friendly are most demanding for advanced catalytic methods for the solvent‐free aminolysis of triglycerides . Biochar‐based (catalyst 6 wt%, yield 98%, reaction time 2.5 hours), zirconia‐alumina nanocatalyst (catalyst 3 wt%, yield 91.6%, reaction time 4 hours), spongy Ni/Fe carbonate‐fluorapatite (catalyst 9.5 wt%, yield 96%, reaction time 2 hours), sodium‐doped nanohydroxyapatite (catalyst 6 wt%, yield 98%, reaction time 2.5 hours), porous BaSnO 3 (catalyst 6 wt%, 96% yield, reaction time 2 hours), CaO/MCM‐41 nanocatalyst (catalyst 5 wt%, yield 96.8%, reaction time 6 hours), and alkali metal‐doped CaO‐based heterogeneous catalysts were reported for natural triglycerides conversion to fatty acid alkyl derivatives. Recently, our group has reported transition metal‐doped CaO for amidation reaction of variety of feedstocks with high catalytic activity .…”

Section: Introductionmentioning

confidence: 99%

One‐pot solvent‐free transformation of natural triglycerides to ester and amide derivatives over CaO@KC nanostructured catalysts

2020

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Summary In the present report, the fatty acid alkyl esters and fatty acid amides were synthesized from natural triglycerides by highly selective solvent‐free one‐step methods using 3.5‐CaO@KC‐400 nanocrystals as a heterogeneous catalyst. A modified wetness chemical impregnation method was used to prepared potassium carbonate‐doped CaO, ZnO, and MgO nanocrystals. The prepared 3.5‐CaO@KC‐400 nanocrystals were found as the most efficient heterogeneous catalyst (5%, w/w) for amidation (6:1 M ratio of diethanolamine/oil, 110°C) and transesterification (12:1 M ratio of methanol/oil, 65°C) of waste cooking oil and took 30 minutes for the completion of both the reactions. The 3.5‐CaO@KC‐400 nanocrystals were found to be efficient at room temperature also and reused for 10 reaction cycles for both reactions. The pseudo‐first‐order kinetic model was applied and the first‐order rate constant was calculated as 0.15 minute−1 and 0.103 minute−1 for the amidation and transesterification reactions of waste cooking oil, respectively.

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Application of microwave irradiation for fabrication of sulfated ZrO2–Al2O3 nanocomposite via combustion method for esterification reaction: process condition evaluation

Cited by 23 publications

References 48 publications

On Electrical Discharge Machining of Non-Conductive Ceramics: A Review

On Electrical Discharge Machining of Non-Conductive Ceramics: A Review

Modelling and Optimisation of the Sol-Gel Conditions for Synthesis of Semi-Hexagonal Titania-Based Nano-Catalyst for Esterification Reaction

One‐pot solvent‐free transformation of natural triglycerides to ester and amide derivatives over CaO@KC nanostructured catalysts

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