Highest Glycerol Conversion Research Articles

Acrolein Production by Gas-Phase Glycerol Dehydration Using PO₄/Nb₂O5 Catalysts.

In this study, modified niobium oxide were prepared to study the addictive effects on the catalytic performance for gas-phase glycerol dehydration. The catalysts were characterized by N2 adsorption/desorption, XRD, NH3-TPD, FT-IR. The amount of phosphoric acid was up to 50 wt% in niobium. As a result, the highest glycerol conversion was achieved over 20 wt% PO4/Nb2O5. It indicates that the optimal amount of phosphoric acid leads the catalyst to have appropriate acidity which is an important factor for gas-phase glycerol dehydration.

HYDROGENOLYSIS OF GLYCEROL: COMPARISON OF CONTINUOUS AND BATCH MODE REACTIONS OVER Ni-ZnO CATALYSTS

Ni-Zn mixed oxide catalysts with varying mole ratios were prepared by the coprecipitation method. These catalysts were characterized by Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction, temperature programmed reduction, H2 chemisorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. Selective hydrogenolysis of glycerol to 1,2-propanediol was carried out with these catalysts both in continuous (fixed bed) and batch (liquid phase) conditions. Higher glycerol conversion was achieved in a fixed bed than in liquid phase glycerol hydrogenolysis. The selectivity to 1,2-propanediol was more in batch mode hydrogenolysis, whereas acetol is the main product in the continuous mode. The activity of catalysts depended on the Ni to Zn mole ratio, which in turn influenced the metal surface area of Ni on ZnO. The catalyst with a Ni to Zn mole ratio of 2 exhibited the highest activity. The observed activity was corroborated with the derived physicochemical properties of the catalysts. Different reaction parameters were studied and optimum reaction conditions were established.

Dual catalysis over ZnAl mixed oxides in the glycerolysis of urea: Homogeneous and heterogeneous reaction routes

In this work, we prepared ZnO, ZnAl2O4, and ZnAl mixed oxides with different metal molar ratios and applied them for synthesizing glycerol carbonate (GC) from glycerol and urea. The reaction routes related to the Zn species over the ZnAl mixed oxides were investigated. The ZnAl mixed oxides were found to consist of two Zn crystalline phases: ZnO and ZnAl2O4. From the reaction results, the ZnAl mixed oxides showed much higher glycerol conversion and GC yield than the ZnO and ZnAl2O4. During the reaction, the dissolution of the Zn species from the ZnO phase over the ZnAl mixed oxides was observed while the ZnAl2O4 phase remained insoluble. The ZnO phase provided a homogeneous reaction route via the dissolved Zn species, resulting in the formation of a Zn complex containing the isocyanate (NCO) and zinc glycerolate. In contrast, the insoluble ZnAl2O4 phase was responsible for not only a heterogeneous reaction route, but also adsorption of the Zn NCO complex on the catalyst. We proposed that the adsorbed Zn NCO complex could play a role as an active site for an additional heterogeneous reaction route. Therefore, the ZnAl mixed oxides exhibited high GC yields through the dual catalysis routes: the homogeneous reaction route over the ZnO phase and the heterogeneous reaction route over the ZnAl2O4 phase.

Metal–Organic Framework Mediated Synthesis of Small‐Sized γ‐Alumina as a Highly Active Catalyst for the Dehydration of Glycerol to Acrolein

AbstractThe dehydration of glycerol into acrolein was investigated over small‐sized γ‐Al2O3 prepared by a metal–organic framework (MOF) templated method. The particle size of alumina strongly affected the final physicochemical properties of γ‐Al2O3 as well as its catalytic activity. The MOF‐derived, small‐sized γ‐Al2O3 (M‐Al2O3) catalyst exhibited higher stability and higher activity in the glycerol dehydration reaction than conventional bulk γ‐Al2O3 and nanorod γ‐Al2O3 owing to enriched intercrystal mesopores and an abundance of accessible acid sites. M‐Al2O3 retained its high glycerol conversion (over 80 %) for nearly 200 h, whereas high acrolein selectivity (74 %) was achieved.

Biodiesel byproduct glycerol upgrading to glycerol carbonate over lithium–oil palm ash zeolite

Mesoporous oil palm ash zeolite (OPAZ) was synthesized and impregnated with various lithium ion loadings (5–15wt%). The synthesized Li–OPAZ catalyst was used to upgrade biodiesel byproduct glycerol to glycerol carbonate (GC) via transesterification pathway. Results indicated that Li–OPAZ sustained the transesterification reaction to appreciably high glycerol conversion (100%) and GC yield (98.1%) under the optimal reaction conditions of 343K, 90min, DMC/glycerol molar ratio of 2, and 2wt% catalyst loading. The crystallinity and framework of zeolite was preserved after lithium incorporation with a slight decrease in pore volume and surface area. However, basicity increased with increased lithium impregnation, explaining the observed high catalytic activity of the theoretical 10wt% Li loaded OPAZ. Hence, 10wt% Li–OPAZ was reused in five successive cycles of experiment with sustained appreciable catalytic activity toward glycerol conversion and GC yield.

Glycerol hydrogenolysis over ruthenium supported on lanthanum modified ZrO2 catalysts

2Ru/x%La-ZrO2 catalysts with different lanthanum contents (x = 0.0, 0.5, 1.0, 2.5, 5.0 10.0) were prepared by the deposition precipitation method and were characterized by XRD, BET surface area, CO chemisorption, CO2-TPD, NH3-TPD, TEM and XPS to determine the effect of lanthanum modification on the catalyst. Then these catalysts were used in the hydrogenolysis of glycerol in the aqueous phase at 190 °C for 8 h. It was found that the lanthanum modification could significantly improve the catalytic efficiency and the 2Ru/1.0%La-ZrO2 catalyst had the highest glycerol conversion and the strongest C–C cleavage ability. The comparison of the catalytic performances of individual catalysts with their physico-chemical characteristics led to the conclusion that the formation of Ruδ− particles, the better dispersion and the improvement of surface acidity and alkalinity had the highest potential for the improvement of the catalytic efficiency. Under the optimized reaction conditions, the reaction over the 2Ru/1.0%La-ZrO2 catalyst obtained the highest EG selectivity 55% and a good conversion of glycerol in less reaction time.

THE SYNTHESIS OF GLYCEROL CARBONATE FROM BIODIESEL BYPRODUCT GLYCEROL AND UREA OVER AMBERLYST 36

The increasing use of biodiesel as renewable fuels leads to the increasing of glycerol amount as a byproduct of biodiesel production. One of the glycerol derivative products that is environmentally friendly and renewable is glycerol carbonate. Glycerol carbonate is commonly used as a raw material for polymers, surfactants, emulsifiers, lubricants, paints, also used in the cosmetics and pharmaceutical industries. In this study, the research was carried out by using a batch reactor with a three-neck flask equipped with reverse cooling, thermometers, mercury stirrer, and heating mantle with the conditions of the reaction temperature around 373 413 K, mole ratio of reactants of urea: glycerol were 1:0,5, 1:1, 1:1,5, 1:2 and 1:4 and the concentration of catalyst were 1%, 2%, 3%, 4% and 5% respectively. Reaction was done for four hours. The results showed that the formation of glycerol carbonate from glycerol and urea using a catalyst Amberlyst 36 is affected by the catalyst concentration, reaction temperature and the ratio of reactants used. The highest glycerol conversion was obtained at 55.07% at a temperature of 393 K with mole ratio of urea and glycerol 1:0,5 and the percentage of catalyst 3% of the amount of glycerol.

Hydrothermal stability improvement of NiPt-containing γ-Al2O3 catalysts tested in aqueous phase reforming of glycerol/water mixture for H2 production

The hydrothermal stability of Ni and NiPt-containing γ-Al2O3 catalysts in aqueous phase reforming (APR) of glycerol/water mixture (C3H8O3/H2O, 10% w/w) was investigated putting in evidence the influence of the preparation method; sol–gel in basic medium (SGB) and impregnation on an in-house prepared sol–gel γ-Al2O3 support (SGI). All developed catalysts were characterized by ICP-AES, TPR-H2, in-situ heating XRD-O2, DSC/TG-N2/O2 and ex-situ reduction of XRD-H2, N2 physisoption and TEM techniques. The results indicate that SGI method and calcination treatment at 750 °C were crucial in extending the catalytic useful life of NiPt-containing γ-Al2O3 catalysts, resulting in an adequate distribution of NiPt metallic particles and good stability of γ-Al2O3 support against the severe hydrothermal conditions of APR process. The SGI method led to form stable NiPt catalysts with relatively big Ni particles and stable hydrothermal properties of γ-Al2O3 support, while the SGB catalysts exhibited well-dispersed Ni particles but unstable catalytic behavior. These last catalysts presented high glycerol conversions during the first hours of APR glycerol/water reaction, however, an important decrease in terms of glycerol conversion was observed after 24 h time-on-stream. The experimental results suggested that the most suitable stable and active catalyst was the NiPt/ASGI7 (better than >NiPt/ASGI6 > NiPt/ASGI5 >>> NiPt/ASGB7). This catalyst showed best catalytic activity and good catalytic stability along 56 h of time-on-stream, reaching, at steady state, highest total glycerol conversion (≈79%) and glycerol into gaseous products (≈57%) in APR reaction of glycerol/water mixture for hydrogen generation.

Roles of texture and acidity of acid-activated sepiolite catalysts in gas-phase catalytic dehydration of glycerol to acrolein

In the search for novel solid acid catalysts for the gas-phase catalytic dehydration of glycerol to acrolein, sepiolite clay minerals were activated with hydrochloric acid to produce acid-activated sepiolite catalysts. The effects of the activation process on the texture and acidity of acid-activated sepiolite, and their roles in gas-phase catalytic dehydration of glycerol to acrolein, were then investigated. A series of acid-activated sepiolite catalysts were made from purified natural sepiolite treated with hydrochloric acid of different concentrations (0–8mol/L) at 80°C, followed by drying at 100°C. The acid-activated sepiolite catalyst samples were characterized using X-ray diffraction, X-ray fluorescence analysis, scanning electronic microscopy, thermogravimetric analysis, N2 adsorption-desorption isotherms, NH3-temperature-programmed desorption. Fourier transform-infrared spectroscopy and pyridine adsorption followed by in situ infrared spectroscopy. The catalytic performances in gas-phase catalytic dehydration of glycerol to acrolein were studied using a vertical fixed-bed reactor. Typically, a glycerol conversion of 92.9%, an acrolein selectivity of 59.4%, and a yield of acrolein of 55.2% were achieved when the gas-phase catalytic dehydration of glycerol was conducted over HCl (2mol/L) acid-activated sepiolite catalyst at 320°C with an aqueous glycerol solution (20wt.%) at a rate of 0.10ml/min as the feedstock and air as the carrier gas at a flow rate of 20ml/min. The activation of the sepiolite with hydrochloric acid followed by drying can eliminate a portion of the zeolitic water in the tunnels, remove part of the magnesium and aluminum cations in the octahedral sheets of sepiolite, unbundle aggregated sepiolite fibers, and partly break the Si-O-Si in the tetrahedral sheets of sepiolite. These factors increased the porosity, the specific surface area and the acidity of the sepiolite. The partial leaching of magnesium and aluminum ions in the octahedral sheet generated octahedral vacancies and created MgOAl+ sites in the octahedral sheets, thereby increasing the amount of Lewis acid sites. Along with penetration of H+ cations into the interlayered space of the sepiolite by an ion-exchange reaction and physicochemical surface adsorption, some breakage of the SiOSi bonds in the tetrahedral sheets generated more SiOH+, thus increasing the quantity of Brønsted acid sites. Furthermore, the strength of acidity of the hydrochloric acid-activated sepiolite was significantly changed after the acid activation. The medium-strong Brønsted acid sites (SiOH+ and H+ adsorbed on the surface) appeared to be beneficial for the high conversion of glycerol and the selectivity to acrolein. Lewis acid sites could facilitate the formation of acetol. Under the reaction conditions mentioned above, the coking on the hydrochloric acid-activated sepiolite catalysts readily occurred, rapidly leading to the decrease of the yield of acrolein.

Modeling of intensified glycerol steam reforming in a heat-exchange integrated microchannel reactor

The aim of this study is to investigate glycerol steam reforming in a heat exchange integrated microchannel reactor involving solid wall separated, rectangular-shaped, parallel reaction and heating channels by means of mathematical modeling techniques. Heat needed for endothermic glycerol steam reforming taking place in Co-Ni/Al2O3 coated channels is supplied by steam flowing in the adjacent channels separated by solid walls. Simultaneous catalytic reaction and heat exchange within the microchannel reactor are modeled by 2D Navier-Stokes equations which were solved by the finite volume method in ANSYS 16.0 platform to study the effects of operational parameters, namely molar inlet steam-to-carbon ratio (S/C) and temperature of the reactive mixture, inlet temperature and velocity of steam, flow configurations of the reactive mixture and steam, and of structural parameters, i.e. reactor wall material and thickness of the wall between the reaction and heating channels on temperature distribution and on glycerol conversion. The results show that increasing S/C from 1 to 6 promotes H2 and CO2 selectivity, having average values of 64.7% and 21.2%, respectively. The same effect, however, suppresses CO selectivity from 12.8% to 10.8% and resulted in CH4 selectivity below 2.7%. Product distribution is found to be in alignment with those of experimental studies reported in the literature. Heating by steam has an obvious contribution to glycerol conversion, which is found to be 73.3% and 63.8% in the presence and absence of steam heating, respectively. Counter- and co-current flow of steam with respect to reactive mixture, however, do not lead to a notable difference in conversion. Increasing steam inlet temperature from 663K to 783K improved conversion by 10.0%, whereas changing steam inlet velocity from 2 to 8m/s did not change reforming channel temperature significantly. Reactor performance is significantly affected by increasing feed temperature of the reactive mixture from 673K to 773K which improved conversion by 11.7%. Higher glycerol conversions are also obtained by using thicker separating walls and thermally conductive wall materials, both of which favor heat flux into the reforming channel. Changing the wall thickness from 4×10−4m to 1.2×10−3m elevates conversion by 1.3%. A similar response is noted upon using silicon carbide instead of AISI steel as the material of construction of the microchannel reactor. In general, selectivity towards H2 is positively correlated with the degree of uniformity of reaction channel temperature, which is also found to dampen undesired CH4 selectivity.

Reforming of glycerol for hydrogen production over Ni based catalysts: Effect of support type

ABSTRACTThis current work focuses on hydrogen production that is a component in syngas by glycerol dry reforming over 15% nickel (Ni) loading supported on different oxides, namely CaO, ZrO2, and La2O3. The screening process was conducted in a fixed-bed reactor at 700°C under atmospheric pressure. It was found that 15% Ni/CaO showed the best performance in screening studies. The effect of temperature and the carbon to glycerol ratio (CGR) was then analyzed for this catalyst. From the analysis, it was seen that 15% Ni/CaO has its optimum condition at 800°C and CGR = 1, where it gives the highest glycerol conversion (XG = 37.66%) and hydrogen yield (YH = 32.45%).

PEMBUATAN BIOADITIF TRIACETIN DENGAN KATALIS PADAT SILICA ALUMINA

Triasetin is a bioaditif to increase the octane number of the gasoline. Triasetin was generated from the reaction between giserol and acetic acid. Glycerol is a byproduct of biodiesel production. Triasetin production can reduce glycerol which is actually a waste by converting it into bioaditif having higher value. The reaction can be accelerated by addition of catalysts either solid or liquid catalyst. The reaction in this study used a solid catalyst types Silica Alumina. The reaction takes place in the three-neck flask reactor which is equipped with heating unit, mixers, and tools to take samples at regular intervals. Variables used in this research is the variety of reaction time and the reaction temperature (70, 80, 90, 100, and 1100C). The concentration of triasetin obtained will be known through the analysis of Gas Chromatography - Mass Spectrometry (GC-MS). The results of the analysis of GC or GC-MS treated or counted so getting glycerol conversion and selectivity of triasetin. The highest glycerol conversion 8,45% occurs at a temperature of 700C the reaction time of 90 minutes with triasetin selectivity 100%.

Characterization of Ag-promoted Ni/SiO2 Catalysts for Syngas Production via Carbon Dioxide (CO2) Dry Reforming of Glycerol

The carbon dioxide (CO2) dry reforming of glycerol for syngas production is one of the promising ways to benefit the oversupply crisis of glycerol worldwide. It is an attractive process as it converts carbon dioxide, a greenhouse gas into a synthesis gas and simultaneously removed from the carbon biosphere cycle. In this study, the glycerol dry reforming was carried out using Silver (Ag) promoted Nickel (Ni) based catalysts supported on silicon oxide (SiO2) i.e. Ag-Ni/SiO2. The catalysts were prepared through wet impregnation method and characterized by using Brunauer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Thermo Gravimetric (TGA) analysis. The experiment was conducted in a tubular reactor which condition fixed at 973 K and CO2:glycerol molar ratio of 1, under atmospheric pressure. It was found that the main gaseous products are H₂, CO and CH4 with H₂:CO molar ratio < 1.0. From the reaction study, Ag(5)-Ni/SiO2 results in highest glycerol conversion and hydrogen yield, accounted for 32.6% and 27.4%, respectively.

Liquid Phase Oxydehydration of Glycerol to Acrylic Acid over Supported Silicotungstic Acid Catalyst: Influence of Reaction Parameters

The liquid phase catalytic oxydehydration of glycerol to acrylic acid over supported silicotungstic acid (SiW) catalysts was carried out in the batch reactor. The effect of oxidizing agent concentration (H2O2), reaction temperatures (70 and 90 °C), types of supports (HZSM-5, SiO2 and Al2O3) and SiW loading (20-60 wt.% based on support) on the conversion and product yield were investigated. The addition of H2O2 and supported SiW catalysts significantly conducted the synergetic positive effects on glycerol conversion and acrylic acid yields as well as other desired products including glycolic acid, formic acid, acetic acid, acrolein and acrylic acid. High reaction temperature was able to enhance high glycerol conversion as the same yield of all desired products. The BET surface area of supported SiW catalysts played much more important role in the activities of oxydehydration of glycerol that this oxydehydration was more remarkable than the acidity of catalysts. Among all supported SiW catalysts, the SiW/HZSM-5 with SiW loading of 30 wt.% exhibited the highest glycerol conversion (85.54%) with the production acrylic acid yield of 30.57 % over 2.74 M H2O2 at 90 °C. The kinetics of glycerol conversion to desired products over supported SiW catalyst was explored.

CaAl-layered double hydroxides as active catalysts for the transesterification of glycerol to glycerol carbonate

Several hydrocalumite-type materials (CaAl-LDHs) were prepared by precipitation using nitrate or chloride salts with and without ultrasound, and aged hydrothermally in autoclave or by refluxing with and without microwaves. These samples were tested as catalysts for the transesterification of glycerol with dimethyl carbonate to glycerol carbonate. After 3h of reaction, all catalysts showed high glycerol conversion (70–84%) and moderate selectivity values to glycerol carbonate (52–65%) accompanied by the formation of low amounts of glycidol (7–15%). These results are very interesting taking into account the low specific surface area of these catalysts (7–25m2/g). No significant catalytic differences were observed between the catalysts. This can be due to the similar surface and basic characteristics observed for all of them. By increasing the reaction time, an increase of conversion was observed arriving practically to total conversion after 24h of reaction, with selectivity to glycerol carbonate in the range 65–75%. Several catalytic reuses favoured the decarboxylation of glycerol carbonate resulting in the formation of higher amounts of glycidol (30%) but still maintaining high selectivity values to glycerol carbonate (70%).

Vapor-phase hydrogenolysis of glycerol to 1,2-propanediol using a chromium-free Ni-Cu-SiO2 nanocomposite catalyst

A Ni-Cu-SiO2 nanocomposite was studied as a catalyst for vapor-phase glycerol hydrogenation to produce 1,2-propanediol (1,2-PDO). Substitution of a small amount (3wt%) of Ni for Cu is beneficial for decreasing the Cu particle size, which would be advantageous for attaining higher 1,2-PDO selectivity and higher glycerol conversion. 92% 1,2-PDO selectivity and 100% glycerol conversion were obtained at 220°C, 30bar, and a weight hourly space velocity of 0.5h−1 over Ni(3)-Cu(77)-SiO2, which were nearly identical to those obtained with the conventional copper chromite (CuO-Cr2O3) catalyst. Therefore, the present Ni(3)-Cu(77)-SiO2 nanocomposite is regarded as a green and efficient catalyst for glycerol conversion into more valuable 1,2-PDO.

Optimum Rebalancing of the 3-Hydroxypropionic Acid Production Pathway from Glycerol in Escherichia coli.

3-Hydroxypropionic acid (3-HP) can be biologically produced from glycerol by two consecutive enzymatic reactions, dehydration of glycerol to 3-hydroxypropionaldehyde (3-HPA) and oxidation of 3-HPA. The pathway has been proved efficient, but imbalance between the rates of the two enzymatic reactions often results in the accumulation of the toxic 3-HPA, which severely reduces cell viability and 3-HP production. In this study, we used UTR engineering to maximally increase the activities of glycerol dehydratase (GDHt) and aldehyde dehydrogenase (ALDH) for the high conversion of glycerol to 3-HP. Thereafter, the activity of GDHt was precisely controlled to avoid the accumulation of 3-HPA by varying expression of dhaB1, a gene encoding a main subunit of GDHt. The optimally balanced E.coli HGL_DBK4 showed a substantially enhanced 3-HP titer and productivity compared with the parental strain. The yield on glycerol, 0.97 g 3-HP/g glycerol, in a fed-batch experiment, was the highest ever reported.

Glycerol Carbonate Production from Biodiesel Waste Over Modified Natural Clinoptilolite

The conversion of glycerol, a byproduct in biodiesel production, to valuable products will improve the economic feasibility of a biodiesel plant. Conversion of glycerol and sodium bicarbonate to glycerol carbonate over natural clinoptilolite was studied in a 500 mL batch reactor for 30–60 min. The optimum condition for better conversion of glycerol was investigated by altering the ratio of reactant, water content, ratio of catalyst-to-glycerol (wt%), diameter of zeolite particles, treatment of natural clinoptilolite, and temperature. The conversion of glycerol has been improved by increasing temperature, concentration of catalyst and decreasing catalyst diameter. Nevertheless, the conversion decreased with increasing of sodium bicarbonate concentration and with higher amount of water. The highest conversion of glycerol was obtained over treated clinoptilolite with diameter catalyst of 0.46 mm, catalyst-to-glycerol ratio of 9 wt%, sodium bicarbonate/glycerol ratio of 3, and water/glycerol of 3 at temperature of 100 °C for 30 min. Applications of sodium bicarbonate as a reactant and water as solvent and natural clinoptilolite as solid catalyst are potential to reduce cost of production and environmental footprint.

Continuous production of lactic acid from glycerol in alkaline medium using supported copper catalysts

With increasing demand for biodiesel, large quantity of crude glycerol has been produced both in Brazilian and world market, and this excess glycerol has become a problem that must be solved. Several studies have been performed with the objective to transform glycerol in value-added chemical products. Lactic acid has wide uses in chemical and food industries, and the hydrothermal transformation of glycerol to lactic acid is presented as an alternative to conventional production process. In this study, the production of lactic acid from glycerol under alkaline conditions, using copper (20wt.% CuO) catalysts supported on Al2O3, ZnO and MgO in continuous flow reaction system was investigated. The catalysts were prepared by impregnation method and characterized by XRF, XRD, N2 adsorption–desorption, TPR, and TPD-CO2 and the dispersion of copper was determined by N2O oxidation. The reaction was carried out at 240°C, 35atm, with space velocity (WHSV) of 2h−1, 10vol.% glycerol solution and NaOH/glycerol molar ratio of 0.5, 0.75 and 1.0. All catalysts showed high conversion of glycerol with yield and selectivity to lactic acid in the range of 80 and 90%, respectively, when the reactions are performed with NaOH/glycerol molar ratio of 1.0.

Synthesis of Alumina Based Alkaline Catalyst for Biodiesel-Derived Glycerol to Polyglycerol

Biodiesel which comes from pure renewable resources provide an alternative fuel option for future. The rapid growth of the biodiesel industry will result in overproduction of less value glycerol and create a superfluity of this impure by-product. The synthesis of alkaline alumina catalyst for polyglycerol production via solvent free base-catalyzed etherification of low value glycerol is reported. The etherification of biodiesel derived glycerol to polyglycerol was studied in a heterogeneous catalysis under solvent free system, using alkalines over γ – alumina catalysts. All the catalysts were prepared by incipient-wetness impregnation of an aqueous solution of alkaline compounds on γ – alumina as a support. The effects of alkaline compound, reaction temperature, catalyst amount, and reaction time in conversion of glycerol to polyglycerol were investigated. The catalyst with potassium loaded on γ -alumina gave the highest basicity and the best catalytic activity for this reaction. The highest glycerol conversion into polyglycerol production was obtained with high yield 79.5% over prepared catalyst respectively. Industrially, the findings attained in this study might contribute towards promoting the biodiesel industry through utilization of its by-products.