Modeling and Optimizing the Synthesis of Urea-formaldehyde Fertilizers and Analyses of Factors Affecting these Processes

Abstract

Previous research into the synthesis of urea-formaldehyde fertilizers was mostly based on orthogonal experimental designs or single factor tests; this led to low precision for synthesis and relatively large ranges of parameters for these processes. To obtain mathematical response models for the synthesis of urea-formaldehyde fertilizers with different nitrogen release properties, a central composite design (CCD) of response surface methodology was used in our research to examine the effects of different reaction times, temperatures, and molar ratios on nitrogen insoluble in either hot or cold water. Our results showed that nitrogen insoluble in cold or hot water from urea-formaldehyde fertilizers were mainly affected by urea: formaldehyde molar ratios. Also, quadratic polynomial mathematical models were established for urea-formaldehyde. According to the models, the optimal process parameters which maximize cold-water-insoluble nitrogen and minimize hot-water-insoluble nitrogen for the synthesis of urea formaldehyde were as follows urea: formaldehyde molar ratio was 1.33, reaction temperature was 43.5 °C, and reaction time was 1.64 h. Under these conditions, the content of cold-water-insoluble nitrogen was 22.14%, and hot-water-insoluble nitrogen was 9.87%. The model could be an effective tool for predicting properties of urea-formaldehyde slow release fertilizers if the experimental conditions were held within the design limits.

Understanding the effect of temperature and time on protein degree of hydrolysis and lipid oxidation during ensilaging of herring (Clupea harengus) filleting co-products

“…Based on the ANOVA analysis (see Supplementary Information; Tables 7-12), the regression models for all six studied responses were significant (p < 0.05). Further, the lack-of-fit values were not significant (p > 0.05) for studied responses, except for TVB-N, suggesting that the model fitted the data very well 51 . The fit of the models was also evaluated by adjusted R 2 values, which minimizes the possibilities of overfitting the models, where a value close to 1.0 represents a good fit of the model 52,53 .…”

An Efficient and Robust Method for Selective Conversion of Aniline to Azobenzene Using nano‐TiO2‐P25‐SO3H, under Visible Light Irradiation

“…This strategy is a reputable means for optimizing the process, which minimizes the number of experiments, and then, the regression model equation would be acquired from quantitative data. The central composite design (CCD) was applied to justify a quadratic model, which is known as a standard RSM design (36–38). The arrangement of CCD resulted in restricting the impacts of uncontrolled factors.…”

“…5. Furthermore, by completing the reaction after 9 h of aniline oxidation, the peaks of GC/MS for azobenzene, aniline and nitrobenzene were obtained at retention times of 8.84, 4.98 and 6.18 min, respectively (39)(40)(41)(42)(43).…”

Nano‐WO3‐SO3H as a New Photocatalyst Insight Through Covalently Grafted Brønsted Acid: Highly Efficient Selective Oxidation of Benzyl Alcohols to Aldehydes

“…In order to precise and appropriate assessment of optimum conditions of reaction, determination was made to apply CCD. The central composite design (CCD) is one of the practical types of response surface model (RSM) which helps to get some amount of information while the number of experimental conditions is maintained minimum without losing accuracy . It is a notable optimization method for improvement responses by a fitted quadratic model which can be shown by following equation:…”