Simple and Green Adipic Acid Synthesis from Cyclohexanone and/or Cyclohexanol Oxidation with Efficient (NH4)xHyMzPMo12O40 (M: Fe, Co, Ni) Catalysts

The oxidation of cyclohexanone and/or cyclohexanol to adipic acid (AA) was performed at 90 °C with a reaction time of 20 h, in the presence of H2O2 as oxidant and transition metal substituted ammonia polyoxometalates of formula, (NH4)xHyMzPMo12O40 (M: Fe, Co, or Ni,  and x = 2.5 or 2.28) as catalysts.  The catalytic results showed that the AA yield is sensitive to the transition metal nature and to the reaction conditions (sample weight and substrate amount). The (NH4)2.29H0.39Co0.16PMo12O40 was found to be the better catalytic system toward AA synthesis from cyclohexanone oxidation, with 40% of AA yield

Trajectory reconstruction for robot programming by demonstration

The reproduction of hand movements by a robot remains difficult and conventional learning methods do not allow us to faithfully recreate these movements because it is very difficult when the number of crossing points is very large. Programming by Demonstration gives a better opportunity for solving this problem by tracking the user’s movements with a motion capture system and creating a robotic program to reproduce the performed tasks. This paper presents a Programming by Demonstration system in a trajectory level for the reproduction of hand/tool movement by a manipulator robot; this was realized by tracking the user’s movement with the ArToolkit and reconstructing the trajectories by using the constrained cubic spline. The results obtained with the constrained cubic spline were compared with cubic spline interpolation. Finally the obtained trajectories have been simulated in a virtual environment on the Puma 600 robot

Study of the Physiological Indices of Sea Cucumber Holothuria tubulosa (Gmelin, 1788) of the Oranaise Coast (Algeria)

Sea cucumbers (Holothuroidea) of the order Aspidochirotes constitute a highly visible and diverse group within marine ecosystems. This echinoderm filled with fundamental ecological functions by its activities detritivore and of bioturbation. In the Mediterranean is more precisely in Algerian waters, among the dominant species is the Holothuria tubulosa hence the interest in the study of this species. A total of 170 specimens are harvested at the sites of Sidi lakhdar and Ain Franin during the period October 2013 to October 2014. The analysis concerns the physiological indices, namely the gonad index (GI) and the repletion index (RI), allowing us to determine the reproductive periods and the various stages of the reproductive cycle of Holothuria tubulosa according to the seasons and the temperature and to see the relation between the feeding period and the reproduction period. The results show that sea cucumbers exhibit fluctuations in physiological indices as a function of temperature and seasons

Evaluation of the Overall Potential Toxicity of Shallow Marine Sediment from Oran Bay by Means of Bioassays of Acute Toxicity

This study investigates the ecotoxicological evaluation of sediment contamination from west Algerian Mediterranean coast (Oran harbour-Ain Franin).The toxicity of sediment and interstitials waters was estimated using bioessays of acute toxicity with brine shrim

Preparation, Characterization, and Catalytic Activity of Tin (Antimony) Substituted and Lacunar Dawson Phosphotungstomolybdates for Synthesis of Adipic Acid

Tin (antimony) substituted and lacunar Dawson phosphotungstomolybdates (a1-K10P2W12Mo5ÿO61, a1-K8P2W12Mo5SnO61 and a-Cs4SnP2W12Mo6O62,and a-Cs3SbP2W12Mo6O62) were synthesized and characterized by Fourier Transform Infra Red (FTIR), nuclear magnetic resonance (31P NMR), Visible Ultra Violet (UV-Vis) spectroscopy, and X-ray diffraction (XRD). Their catalytic properties were examined in the oxidation reaction of cyclohexanone at 90 °C and that of cyclohexene at 70 °C to adipic acid (AA), in presence of hydrogen peroxide and in free solvent. The effects of catalyst/substrate molar ratios, hydrogene peroxide flow rate, heteropolysalt composition, and cyclohexanol addition on AA yields were studied. The Cs4SnP2W12Mo6O62 (the most efficient) led to 61 % of AA yield from the cyclohexanone oxidation using a catalyst/substrate molar ratio of 13.3×10-4, H2O2 flow rate of 0.5 mL/h, and a reaction time of 20 h. Copyright © 2019 BCREC Group. All rights reserve

Preparation, characterization of mixed-valence antimony-tin phosphomolybdic polyoxometalates and application in the cyclohexanone oxidation in the presence of hydrogen peroxide

In this work, a series of polyoxometalates (POMs), as soluble salts of formula Sn1.5PMo12O40, SbPMo12O40 and $\mathrm{H}_{3-x}\mathrm{Sn}_{x1}\mathrm{Sb}_{x2}\mathrm{PMo}_{12} \mathrm{O}_{40}$ ($x=2x_{1}+3x_{2}$ and $x_{1}$, $x_{2}=$ 0–0.75) were synthesized using the cationic exchange method under stoichiometric conditions. They were characterized and tested in the oxidation of cyclohexanone using hydrogen peroxide in the absence of organic solvent, co-catalyst phase transfer compounds or surfactants. UV–Visible and X-ray photoelectron spectroscopic analyses showed a partially reduced state of POM with coexistence of the couples Mo(VI)/Mo(V), Sb(V)/Sb(III) and Sn(IV)/Sn(II), without affecting their structure, results confirmed by FT-IR and Raman spectroscopies. The reversible cyclic voltammetry analysis evidenced the valence change of the Mo species, Mo(VI)/Mo(V). The POMs are found to be active in the cyclohexanone oxidation reaction and among them the most efficient is $\mathrm{H}_{0.75}\mathrm{Sb}_{0.75}\mathrm{PMo}_{12}\mathrm{O}_{40}$ with 49% of adipic acid yield

Preparation, characterization of mixed-valence antimony-tin phosphomolybdic polyoxometalates and application in the cyclohexanone oxidation in the presence of hydrogen peroxide

In this work, a series of polyoxometalates (POMs), as soluble salts of formula Sn1.5PMo12O40, SbPMo12O40 and $\mathrm{H}_{3-x}\mathrm{Sn}_{x1}\mathrm{Sb}_{x2}\mathrm{PMo}_{12} \mathrm{O}_{40}$ ($x=2x_{1}+3x_{2}$ and $x_{1}$, $x_{2}=$ 0–0.75) were synthesized using the cationic exchange method under stoichiometric conditions. They were characterized and tested in the oxidation of cyclohexanone using hydrogen peroxide in the absence of organic solvent, co-catalyst phase transfer compounds or surfactants. UV–Visible and X-ray photoelectron spectroscopic analyses showed a partially reduced state of POM with coexistence of the couples Mo(VI)/Mo(V), Sb(V)/Sb(III) and Sn(IV)/Sn(II), without affecting their structure, results confirmed by FT-IR and Raman spectroscopies. The reversible cyclic voltammetry analysis evidenced the valence change of the Mo species, Mo(VI)/Mo(V). The POMs are found to be active in the cyclohexanone oxidation reaction and among them the most efficient is $\mathrm{H}_{0.75}\mathrm{Sb}_{0.75}\mathrm{PMo}_{12}\mathrm{O}_{40}$ with 49% of adipic acid yield

Overcoming the caking phenomenon in olive mill wastes

The use of olive mill wastes (orujillo) within coal fired power stations in the UK has led to unexpected difficulties with material caking within the fuel handling plant. This study replicated orujillo caking on a laboratory scale using a planetary ball mill and explored the impact of mill parameters (speed, volume, and duration) on the caking phenomenon. The impact of orujillo composition was examined for 4 sections of fresh and dried orujillo (whole, pulp 0-850 µm, pulp 850-3350 µm, and cluster 3350 µm+) for set milling conditions. Caking was induced by heat generation within the mill and was most prevalent in the pulp section of orujillo. Caking was brought on by a glass transition step, which was measured to be around 97-98 °C for a moisture content of 6-7% in a differential scanning calorimeter (DSC). Caking was the result of the bulk moisture content (14-18%) being higher than the standard moisture content of orujillo (< 12%), and can be mitigated through drying. Thus the key to overcoming orujillo caking in fuel handling plants is through moisture content control. Additionally, as the caking issue is most prevalent in the pulp section, all fines below the required combustion particle size (typically < 1 mm) should be removed prior to comminution and sent directly to the burner. This would also reduce the comminution load by nearly 50%, increase the energy potential of the fuel, and remove the most problematic section of orujillo from the fuel handling plant

Keggin-Type Mixed Polyoxomolybdates Catalyzed Cyclohexanone Oxidation by Hydrogen Peroxide: In Situ IR Pyridine Adsorption

SSCI-VIDE+CDFA+NESInternational audiencePolyoxometalate