Production of Bitumen Modified with Low-Molecular Organic Compounds from Petroleum Residues. 3. Tar Modified with Formaldehyde

Abstract

The chemical modification of tar with formaldehyde as 37% aqueous solutionhas been studied in the presence of the catalysts. Hydrochloric acid, sulfuric acid, sodium hydroxide and acid tar were used as the catalysts. The effect of the catalyst nature and amount, as well as temperature, process time and initial components ratio on the softening point, penetration, brittle point and adhesion to crushed stone has been determined. The structure of the modified tars was confirmed by IR spectroscopy. The structural-group composition was determined. Arene-formaldehyde resins have been synthesized on the basis of toluene and modified tars using hydrochloric acid as a catalyst. The synthesized resins were characterized using IR spectroscopy. The chemistry of the tar modification with formaldehyde has been proposed.

Isolation of Antibacterial Nano-Hydroxyapatite Biomaterial from Waste Buffalo Bone and Its Characterization

“…Its characteristic is presented in the previous work. 19 Formaldehyde was used as 37% aqueous solution (formalin). The catalysts were concentrated sulfuric acid (density 1.83 g/cm 3 ) and concentrated hydrochloric acid (density 1.19 g/cm 3 ).…”

“…Tar modification with formaldehyde was caried out according to the procedure described previously. 19 The conditions and main characteristics of the formaldehyde modified tars (FMT) are represented in Table 2.…”

“…Previously, we established that tar chemical modification with formaldehyde should be carried out at the temperature of 353-393 K for 1 h with formalin concentration of 5 wt% relative to tar, and sulfuric acid as a catalyst in the amount of 2.5 wt% relative to tar. 19 The experiments were carried out with changing one parameter of the process and remaining other parameters constant, therefore we established only the tendency of parameters effect on the process proceeding and the real optimal conditions could not be determined.…”

“…If formaldehyde is used, it reacts with aromatic compounds of tar. The formed areneformaldehyde resins are modifiers of bitumen properties on the one hand, and on the other hand, the transition of oils into resins takes place, 19 which also improves the bitumen properties. When petroleum residue is modified with maleic anhydride, 18 the molecules of anhydride react with bitumen components.…”

“…20 This work is a continuation of study described by us previously. 19 The aim of this work is to determine the optimum conditions for chemical modification of tar with formaldehyde. To define optimal conditions for chemical modification of tar with formaldehyde, a series of experiments was carried out.…”