alkaline hydrolysis
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A straightforward and transition metal-free one-pot protocol to synthesize halobenzo[b]furans has been developed employing simple and easily available starting materials such as O-aryl carbamates and alkynylsulfones. The fine-tuning of the different steps involved was key to achieving a successful one-pot procedure. Initially, a directed ortho-lithiation process, which uses the carbamate as the directed metalation group, was crucial in providing access to O-2-alkynylaryl N,N-diethyl carbamates by a direct alkynylation of the o-lithiated carbamate, with arylsulfonylalkynes as electrophilic reagents. Cyclization of the generated o-alkynylaryl carbamates was successfully accomplished through a strategy involving in situ carbamate alkaline hydrolysis under conventional heating or microwave irradiation, coupled with a subsequent heterocyclization step delivering the desired benzo[b]furans. A wide variety of new halobenzo[b]furans has been synthesized and their utility has been demonstrated by their further transformation.

Alkaline hydrolysis rates coefficients for the series of methyl 3-(7-substituted-1-naphthyl) propynoate was calculated in 70%v/v dimethylsulphoxide-water at various temperatures (25,30,40, and 50̊ C). The pKa values of 3-(7-substituted-1-naphthyl) propynoic acid and (E)- 3-(7-substituted-1-naphthyl) propenoic acid calculated in 80%w/w 2-methoxyethanol-water at room temperature (25.0̊ C). logk2 of esterification rate coefficients for 3-(7-substituted-1-naphthyl) propynioc acid and (E)-3(7-substituted-1-naphthyl) propenioc acid with DDM have been measured at 30.0̊ C. Reversed substituent dipolar effects were found in the ionization reaction. In the esterification reaction with DDM the result show similar but reduced substituted effects. Rate retardations was found in the alkaline hydrolysis. It could be result from steric effect or reversal of substituent dipolar effect with a combination of steric effect.

The influence of humic aggregates in water solution upon the chemical stability under basic conditions of different substrates has been reviewed. The kinetic behavior of each substrate has been modelized in terms of micellar pseudophase model.

The paper presents the results of studies of nanosized titanium dioxide (TiO2) samples synthesized by alkaline hydrolysis. The surface properties of the samples were modified using high-temperature annealing. As a result, samples with a specific surface area of 31-203 m2/g were obtained. The specific capacity of TiO2 in lithium and sodium cells was determined. It is noted that the nature of the curves obtained, the specific capacity and its stability during cycling depend on the nature of the alkali metal cation and the surface properties of TiO2.

AbstractFeathers, burdensome waste from the poultry industry, can be a cheap source of keratin, a protein with excellent physicochemical, biological, and mechanical properties. Acid and alkaline hydrolyses are usually adopted for isolation of keratin from its natural resources. This study aimed at assessing the statistically significant effect of input variables in the alkaline hydrolysis of keratin from chicken feathers on the process yield and on the molecular weight of peptides obtained. The effect of the volume ratio of 1M NaOH to the feathers’ mass, the hydrolysis time, and the shaking speed of the reaction mixture on the process yield were analyzed. The use of statistical analysis at the design step of experiment allowed reducing the trial number from 27 to 9. Among the input variables analyzed, only the volume ratio of 1M NaOH to the feathers’ mass had a significant effect on the process yield, while none of them significantly affected the molecular weight of the peptides obtained. All hydrolysates were dominated by two peptides’ fractions, with molecular weights of ca. 130 and 250 kDa, and mixture of many peptides of weight close to 10 kDa and smaller. Alkaline hydrolysis of feather keratin yielded protein hydrolysates soluble over a wide pH range.

Abstract Aiming at the shortcomings of traditional methods for detecting the content of Alkaline Hydrolysis Nitrogen (AHN) and pH value in soil, such as time-consuming and labor-consuming, this paper proposes a rapid quantitative inversion method based on hyperspectral analysis of AHN content and pH value. This method uses db4 discrete wavelet denoising (DWD) and wavelet denoising normalization (DWD-N) to carry out Pearson correlation analysis, and two methods, Ridge regression and Partial Least Squares Regression (PLSR), were used to compare the accuracy of hyperspectral inversion of soil AHN content and pH value. Experiments have demonstrated that in the inversion of the AHN content prediction model, Ridge regression has a good modeling effect under the DWD-N model, where R2=0.647, RMSE=7.067mg/kg. PLSR has good prediction effect under DWD-N, where R2 is the highest of 0.792, RMSE is 3.438mg/kg; in the model inversion of pH prediction, the full-band PLSR modeling effect of pH value under DWD pretreatment is the best, which modeling set and the prediction set of R2 is 0.826 and 0.875, the RMSE is 0.217 mg/kg and 0.191 mg/kg respectively.

Abstract Concrete as alkaline (pH ∼12,5) and moist material can cause deterioration of polyvinyl chloride (PVC) floor coverings and adhesives through alkaline hydrolysis. Attempts to prevent alkaline hydrolysis have mainly been made by installing PVC floor coverings above ‘dry-enough’ concrete or by using self-levelling low-alkali (pH ∼11…11,5) screeds between concrete and floor coverings. In this study, screed, adhesive and PVC floor covering combinations have been varied by using different floor covering conditions in laboratory test series. VOC emissions have been analysed from flooring material samples (Bulk-VOC). The test samples have been measured for two to three years after installing floor covering. According to the results, a 5 mm layer of low-alkali screed (pH less than 11,5) will effectively protect PVC flooring against alkaline hydrolysis. It could also be concluded that the pH level immediately under floor covering has a better correlation with VOC emission than the RH of concrete in the moment of installing the floor covering.