Urea Synthesis Research Articles

Photoelectrochemical Urea Synthesis from Nitrate and Carbon Dioxide on GaN Nanowires

Photoelectrochemical Urea Synthesis from Nitrate and Carbon Dioxide on GaN Nanowires

Integration of the Urea Fertilizer Industry Process Safety Index

The chemical industry has different stages of the production process, depending on the materials used and the products produced. Typically, previous approaches only use one or two parameters. The focus of this study is on a safety assessment metric called the Index Process Safety Value (IPSV). The evaluation process using IPSV involves initially identifying parameters, evaluating each parameter using IPSV, and then integrating the assessments. Integration assessments can be used to ascertain the level of risk involved in the standardization process. Standardization is carried out to ensure the specific attributes of each industrial process flow. Where in this standardization there are variations in index values and levels of potential danger. This main and initial process is the core of the Urea production process stages. Of the several stages of the urea production process, the one with the highest level of danger is during the production of Urea in the synthesis process, namely in the Reactor (DC101) with an index value of 0.4, while the lowest is in the urea synthesis process, namely in the Condenser (EA101) with the average index value is 0.28. This IPSV method can be used to analyze process safety, especially for the urea synthesis unit at Factory 5 of PT Pupuk Kaltim

Synthesis and research of polyurethane urea with 2-(2-aminoethoxy)ethan-1-amine and 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propane-1-amine as macrochain extenders, and compositions with ifosphamide based on them

Polyurethane urea (PUU) was synthesized using macrochain extenders of 2-(2-aminoethoxy)ethan-1-amine (DA1) and 3-{2-[2-(3-aminopropoxy)ethoxy]ethoxy}propan-1-amine (DA3) at a molar ratio of 4,4'-diaminodiphenylmethane (DADP) to DA1 and DA3 as 30:70; 50:50; and 70:30. The tensile strength () of PUU is in the range of 0.74–2.21 MPa, and the relative elongation at break () is 27.4–1003%. According to the DSC method, the studied PUUs are single-phase systems. The glass transition temperature (Tg) of the PUU DA1 series is from 21.920C to –39.480C, and the glass transition temperature for the PUU DA3 is from –20.040C to –33.960C. Based on the synthesized PUUs, composite materials were prepared containing 1 wt.% of ifosfamide (IFO) (=0.74–2.21 MPa, and =31.8–276.3%). According to the results of thermophysical studies, the compositions with IFO are single-phase systems with Tg of –24.80C to –36.220C. Thus, the introduction of IFO into the composition leads to an increase in the packing density of the macrochain, a decrease in the size of the free volume and, consequently, a decrease in the mobility of the blocks in space and a decrease in Сp. Compositions with IFO are resistant to temperatures of ~2500C, which allows thermal sterilization before use. Using the HPLC-UV method, the dynamics of IFO release from samples of PUU compositions synthesized at a molar ratio of DADP:DA1 as 0.5:0.5 and DADP:DA3 as 0.7:0.3 was investigated. It was established that IFO is released within 60 days from compositions based on PUU DA3 in the amount of 29.6%, and from compositions based on PUU DA1 in the amount of 42% with respect to the total amount of IFO introduced. The resulting composites are promising materials for medicine as means of local prolonged therapeutic action.

Fundamentals and Rational Design of Heterogeneous C‐N Coupling Electrocatalysts for Urea Synthesis at Ambient Conditions

AbstractElectrocatalytic C‐N coupling reaction is regarded as a promising strategy for achieving clean and sustainable urea production by coreducing CO2 and nitrogen species, thus contributing to carbon neutrality and the artificial nitrogen cycle. However, restricted by the sluggish adsorption of reactants, competitive side reactions, and multistep reaction pathways, the electrochemical urea production suffers from a low urea yield rate and low selectivity so far. In order to comprehensively improve urea synthesis performance, it is crucial to develop highly efficient catalysts for electrochemical C‐N coupling. In this article, the catalyst‐designing strategies, C‐N coupling mechanisms, and fundamental research methods are reviewed. For the coreduction of CO2 and different nitrogen species, several prevailing reaction mechanisms are discussed. With the aim of establishing the standard research system, the fundamentals of electrocatalytic urea synthesis research are introduced. The most important catalyst‐designing strategies for boosting the electrocatalytic urea production are discussed, including heteroatom doping, vacancy engineering, crystal facet regulation, atom‐scale modulation, alloying and heterostructure construction. Finally, the challenges and perspectives are proposed for future industrial applications of electrochemical urea production by C‐N coupling.

Selective Electrosynthesis of Urea via C−N Coupling: Current Status, Challenges and Future Prospects

AbstractSelective electrosynthesis of urea from carbon source (CO2) and nitrogen (N2, NO3−, NO2−) source provides a sustainable strategy for production of essential nitrogen‐based fertilizers. The traditional technology of urea synthesis employs two consecutive processes, synthesis of NH3 from N2+H2 and urea from NH3+CO2, which always involves high energy consumption and environmental concerns. By contrast, urea electrosynthesis avoids the above harsh steps and meanwhile has higher atomic economy. Herein, we present a comprehensive review on the progress and prospect of urea electrosynthesis from abundant carbon and nitrogen sources via coupling of C−N under ambient conditions, and also discuss the mechanism researches, strategies of substrates activation, current challenges and future opportunities of urea electrosynthesis. The urea electrosynthesis via C−N coupling realizes abundant and low‐cost inorganic carbon and nitrogen sources for efficient resource utilization and provides guidance and reference for C−C, C−S or other coupling reactions.

Efficient Solar Driven Upgrading of N2 to Urea Through Photoredox Reactions on Pt Cluster/TiO2

AbstractSynthetic nitrogen fertilizers, such as urea, are instrumental in augmenting agricultural output and addressing the demands of a growing population. Nevertheless, conventional urea production heavily relies on energy‐intensive processes. In this study, an environmentally friendly photocatalytic method is proposed for directly and selectively synthesizing urea from nitrogen (N2) and methanol (CH3OH using a Pt cluster‐decorated TiO2 catalyst (Pt cluster/TiO2). Remarkably, the Pt cluster/TiO2 exhibits outstanding urea synthesis performance with a rate of 105.68 µmol g−1 h−1 and N‐selectivity of 97.29 ± 0.79%, representing the highest level of photocatalytic urea synthesis from N2. Further analysis with density functional theory (DFT) calculation reveals that the “σ–π*” donor–acceptor interaction occurred between Pt clusters and N2, efficiently reducing the N2 hydrogenation barrier. EPR experiments demonstrate that photogenerated electrons (e−) and hole (h+) are synchronously consumed through N2 reduction and CH3OH oxidation, thereby accelerating urea synthesis. The crucial step of C─N coupling is initiated by the reaction between *NH─NH and *CHO intermediate, facilitated by the low energy barrier on Pt cluster/TiO2. This work suggests an mild route of urea production and provides profound insights into the underlying chemistry of the C─N coupling reaction, which can guide the sustainable synthesis of essential indispensable chemicals.

Hereditary Amino Acid Metabolism Disorders and Urea Cycle Disorders: to Practicing Physician

Hereditary amino acid metabolism disorders (aminoacidopathies) are clinically and genetically heterogeneous group of hereditary metabolic diseases caused by enzymes deficiency involved in amino acid metabolism, that finally leads to progressive damage of central nervous system, liver, kidneys, and other organs and systems. Hereditary urea cycle disorders occur because of enzyme deficiency leading to impaired urea synthesis and hyperammoniemia in patients. The age of disease onset and clinical manifestations severity range from milder, intermittent forms to severe, manifesting in the first hours of life. Expanded neonatal screening (implemented in Russian Federation at 01.01.2023) allows to diagnose diseases from these groups in the first days of life, to prescribe timely pathogenetic therapy. Altogether it helps to prevent the development of disease severe complications. Raising awareness about hereditary aminoacidopathies and urea cycle disorders among pediatricians, neonatologists, neurologists, gastroenterologists, ophthalmologists is a topical issue of modern pediatrics.

The influence of steroidal implants and manganese sulfate supplementation on growth performance, trace mineral status, hepatic gene expression, hepatic enzyme activity, and circulating metabolites in feedlot steers.

Angus-cross steers (n = 144; 359 kg ± 13.4) were used to assess the effect of dietary Mn and steroidal implants on performance, trace minerals (TM) status, hepatic enzyme activity, hepatic gene expression, and serum metabolites. Steers (n = 6/pen) were stratified by BW in a 3 × 2 factorial. GrowSafe bunks recorded individual feed intake (experimental unit = steer; n = 24/treatment). Dietary treatments included (MANG; 8 pens/treatment; Mn as MnSO4): (1) no supplemental Mn (analyzed 14mg Mn/kg DM; Mn0); (2) 20mg supplemental Mn/kg DM (Mn20); (3) 50mg supplemental Mn/kg DM (Mn50). Within MANG, steers received a steroidal implant treatment (IMP) on day 0: (1) no implant; NO; or (2) combination implant (Revalor-200; REV). Liver biopsies for TM analysis and qPCR, and blood for serum glucose, insulin, non-esterified fatty acids, and urea-N (SUN) analysis were collected on days 0, 20, 40, and 77. Data were analyzed as a randomized complete block with a factorial arrangement of treatments including fixed effects of Mn treatment (MANG) and implant (IMP) using PROC MIXED of SAS 9.4 using initial BW as a covariate. Liver TM, serum metabolite, enzyme activity, and gene expression data were analyzed as repeated measures. No MANG × IMP effects were noted (P ≥ 0.12) for growth performance or carcass characteristic measures. Dietary Mn did not influence final body weight, overall ADG, or overall G:F (P ≥ 0.14). Liver Mn concentration increased with supplemental Mn concentration (MANG; P = 0.01). An IMP × DAY effect was noted for liver Mn (P = 0.01) where NO and REV were similar on day 0 but NO cattle increased liver Mn from days 0 to 20 while REV liver Mn decreased. Relative expression of MnSOD in the liver was greater in REV (P = 0.02) compared to NO and within a MANG × IMP effect (P = 0.01) REV increased liver MnSOD activity. These data indicate current NASEM Mn recommendations are adequate to meet the demands of finishing beef cattle given a steroidal implant. Despite the roles of Mn in metabolic pathways and antioxidant defense, a basal diet containing 14mg Mn/kg DM was sufficient for the normal growth of finishing steers. This study also provided novel insight into how implants and supplemental Mn influence genes related to arginine metabolism, urea synthesis, antioxidant capacity, and TM homeostasis as well as arginase and MnSOD activity in hepatic tissue of beef steers.

Synthesis of urea from CO2 and N2 fixation under mild conditions using polarized hydroxyapatite as a catalyst

A modified green ceramic converts N2 and CO2 to urea using mild reaction conditions and UV irradiation. The addition of a small amount of NO to the feed gas mixture allows the UV illumination to be removed and enhances the yield and selectivity.

Electrocatalytic C–N coupling for urea synthesis: a critical review

Strategies for building efficient electrocatalytic urea synthesis systems.

Ambient electrosynthesis of urea with nitrate and carbon dioxide over a CuRu alloy catalyst.

Urea synthesis under mild conditions starting from the electrocatalytic coupling of carbon dioxide (CO2) and nitrate represents a promising alternative experimentally to conquer the huge energy consumption in the industrial Haber-Bosch process. Herein, an electrocatalyst consisting of CuRu alloy nanoparticles on carbonized cellulose (CuRu-CBC) is designed and realizes the urea yield rate of 394.85 ± 16.19 μg h-1 mgcat-1 and an ultrahigh faradaic efficiency (FE) of 68.94 ± 3.05% at -0.55 V (vs. RHE) under ambient conditions. Further XAS analyses indicated that the favored internal electron transfer between Cu and Ru dual active sites significantly improved the C-N coupling activity. Various characterizations, including in situ ATR-SEIRAS and DEMS analysis highlighted the favorable generation of key intermediates *CO and *NH, making CuRu-CBC a promising catalyst for urea synthesis.

Screening Transition Metal Electrodes for Achieving near 100% Selectivity to Urea via Electroreduction of NO3- and CO2 at 100 mA/cm2 Current Density

The current method to synthesize urea is highly energy intensive and has a massive carbon footprint. Electrochemical synthesis of urea from NO3- and CO2 is an attractive and sustainable way...

Catalysts for C-N coupling in urea electrosynthesis under ambient conditions from carbon dioxide and nitrogenous species.

Urea is an indispensable nitrogen-containing organic compound in modern human life. However, the current industrial synthesis of urea involves ammonia, which is produced through the Haber-Bosch process under harsh reaction conditions, causing huge energy consumption and heavy environmental pollution. Electrochemical reduction of carbon dioxide (CO2) and nitrogenous species (N2, NOx- and NO) have achieved significant progress, offering a promising approach for the electrochemical C-N coupling to produce urea under ambient conditions. Urea synthesis driven by renewable electricity represents a suitable alternative to the traditional process, contributing to the goal of carbon neutrality and nitrogen cycles. However, challenges such as low yield rate, poor selectivity and unveiled reaction mechanisms still need to be addressed. This review provides a summary of the latest catalysts utilized in urea electrosynthesis, aiming to provide guidance and prospects for the development of high-performance catalysts.

Electrochemical strategies for urea synthesis via C–N coupling of integrated carbon oxide–nitrogenous molecules reduction

The electrochemical coupling of C and N has sparked considerable research attention, heralded as a capable method to curb carbon and nitrogen emissions while concurrently storing surplus renewable electricity in...

Durable and efficient urea electrosynthesis using carbon dioxide and nitrate over defect-rich In2O3 nanotubes

A defect-rich In2O3 electrocatalyst is highly durable and efficient for sustainable urea synthesis via co-reduction of CO2/NO3− under mild conditions.

Electroreduction of CO2 and nitrate for urea synthesis on a low-coordinated copper catalyst

Electroreduction of CO2 and NO3- to urea (ECNU) offers a fascinating route for migrating NO3- pollutants and synthesizing valuable urea. Herein, low-coordinated copper (L-Cu) is developed as an effective ECNU...

Utilisation of carbon dioxide and nitrate for urea electrosynthesis with a Cu-based metal-organic framework.

It is important and challenging to utilise CO2 and NO3- as a feedstock for electrosynthesis of urea. Herein, we reported a stable 2D metal-organic framework (MOF) Cu-HATNA, possessing planar CuO4 active sites, as an efficient electrocatalyst for coupling CO2 and NO3- into urea, achieving a high yield rate of 1.46 g h-1 gcat-1 with a current density of 44.2 mA cm-1 at -0.6 V vs. RHE. This performance surpasses most of the previously reported catalysts, revealing the great prospects of MOFs in sustainable urea synthesis.

Efficient urea synthesis via one-step N–C–N coupling: strong metal–support interaction-driven planar Cu clusters on two-dimensional Mo2C MXene

The anchoring of the Cu cluster on Mo2C substrate can achieve a planar configuration, effectively boosting urea synthesis via a one-step mechanism.

Transition metal oxide clusters: advanced electrocatalysts for a sustainable energy future.

The comprehensive utilization of sustainable green energy is essential to face the global energy and environmental crisis. The oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and electrocatalytic urea synthesis (EUS) are the pivotal electrocatalytic processes, necessitating the development of low-cost electrocatalysts with high efficiency. Small-sized transition metal oxide (TMO) clusters have attracted a lot of attention because of their exceptional qualities, such as exhibiting a dense array of low-coordinated metal active sites (e.g. abundant metal cation defects and oxygen vacancy), amorphous structures with high surface energy, high atom utilization efficiency, and cost-effectiveness. Furthermore, the synergistic actions between metal clusters and TM-Nx single atom active sites remarkably boost up the electrocatalytic performances, corroborated by density functional theory (DFT). More efforts in this comprehensive feature article are expected to achieve insights into the fundamental understanding of electrocatalytic reaction mechanisms in our lab and serve as a guide for creating cutting-edge electrocatalysts of transition metal oxide clusters.

Exploration of earth-abundant transition metals (Fe, Co, Ni) doped on W18O49 system as electrocatalysts for urea productiont

The conversion of inert N2 and CO2 into urea by electrocatalytic technology not only reduces the cost of urea synthesis in future, but also alleviates the environmental pollution problem caused by carbon emission in traditional industrial production. However, facing downside factors such as strong competitive reactions and unclear reaction mechanism, the design of high-performance urea catalysts is imminent. This study demonstrates that W18O49 system doped heteronuclear metals (TM = Fe, Co, Ni) can effectively solve the problem of competitive adsorption between N2 and CO2 and realize the co-adsorption of N2 and CO2 at diverse sites. Their theoretical limiting voltages for urea production on TM-W18O49 (TM = Fe, Co, Ni) systems are −0.46 V, −0.42 V and −0.52 V, respectively. The results are all lower than that of the contrastive voltage in pristine W18O49 system (-0.91 V), further indicating the rationality and necessity of single-atom doped strategy for the co-reduction of two molecules. Specially, Co-W18O49 can theoretically inhibit the side reactions of NRR, CO2RR, and HER, which deserve future experimental exploration in future. The study suggests that doping heteronuclear metal into transition metal oxides is a feasible scheme to solve competitive adsorption and improve catalytic performance.