Revisiting the mechanism of β-O-4 bond cleavage during acidolysis of lignin VII: acidolyses of non-phenolic C6-C2-type model compounds using HBr, HCl and H2SO4, and a proposal on the characteristic action of Br− and Cl−

A non-phenolic C6-C2-type lignin model compound with the β-O-4 bond, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl)ethanol (I), was acidolyzed in aqueous 82% 1,4-dioxane containing HBr, HCl, or H2SO4 with a concentration of 0.2 mol/L at 85 ℃ to examine the differences between these acidolyses. Compound I primarily converted to an enol ether compound, 1-(2-methoxyphenoxy)-2-(3,4-dimethoxyphenyl)ethene (II), via the benzyl cation followed by acidolytic β-O-4 bond cleavage regardless of the acid-type, although the disappearance rates of compound I were remarkably different (HBr > HCl >> H2SO4). Acidolyses of compound II using these acids under the same conditions showed a similar tendency, but the rate differences were much smaller than in the acidolyses of compound I. Acidolyses of the α-methyl-etherified derivative of compound I (I-α-OMe) using these acids under the same conditions suggested that the formation rates of the benzyl cation from compound I-α-OMe (also from compound I) are not largely different between the acidolyses using these acids, but those of compound II from the benzyl cation are remarkably different. Acidolysis of the α-bromo-substituting derivative of compound I (I-α-Br) using HBr under the same conditions showed a characteristic action of Br¯ in the acidolysis. Br¯ adds to the benzyl cation generated from compound I or I-α-OMe to afford unstable compound I-α-Br, resulting in acceleration of the formation of compound II and of the whole acidolysis reaction.

Enzymatic Synthesis of O-Methylated Phenophospholipids by Lipase-Catalyzed Acidolysis of Egg-Yolk Phosphatidylcholine with Anisic and Veratric Acids

Lipase-catalyzed acidolysis reactions of egg-yolk phosphatidylcholine (PC) with anisic (ANISA) and veratric (VERA) acids were investigated to develop a biotechnological method for the production of corresponding biologically active O-methylated phenophospholipids. Screening experiments with four commercially available immobilized lipases indicated that the most effective biocatalyst for the incorporation of ANISA into phospholipids was Novozym 435. None of the tested enzymes were able to catalyze the synthesis of PC structured with VERA. The effects of different solvents, substrate molar ratios, temperature, enzyme loading, and time of the reaction on the process of incorporation of ANISA into the phospholipids were evaluated in the next step of the study. The mixture of toluene/chloroform in the ratio 9:1 (v/v) significantly increased the incorporation of ANISA into PC. The acidolysis reaction was carried out using the selected binary solvent system, 1/15 substrate molar ratio PC/ANISA, 30% (w/w) enzyme load, and temperature of 50 °C afforded after 72 h anisoylated lysophosphatidylcholine (ANISA-LPC) and anisoylated phosphatidylcholine (ANISA-PC) in isolated yields of 28.5% and 2.5% (w/w), respectively. This is the first study reporting the production of ANISA-LPC and ANISA-PC via a one-step enzymatic method, which is an environmentally friendly alternative to the chemical synthesis of these biologically active compounds.

The study of the modification methylphenylsiloxane resin with dimethylene links metal compounds and boric acid

In this paper we study the effect of modified metal compounds and boric асid (E), where Element = B, Ti, Zr, Al on the thermal stability of methylphenylsiloxane resins derived from alkoxysilanes. Currently interested in the reaction for producing oligosilsesquioxanes based on acidolysis alkoxysilanes. In this regard, the author was tasked with obtaining new methylphenylsiloxane resins with different properties. In this paper, we study the properties of new methylphenylsiloxane resins (MFSS), modified metal compounds and boric acid. New MFSS obtained by a new universal technology-acidolysis mixture of methyltriethoxysilane (MTEOS) and phenyltriethoxysilane (PHTEOS) with various radicals, which are environmentally friendly raw materials. The obtained MFSS were characterized by NMR spectroscopy on 1H and 29Si nuclei. The spectra were recorded at room temperature in deuteroacetone using a Bruker AM-360 Fourier spectrometer. 29Si NMR spectra were measured using the pulse program "Inverse Gated Heteronuclear Decoupling". Thermogravimetric analysis was performed on the device Derivatograph-H (firm Mom). TGA studies were carried out in the argon atmosphere and in air at a heating rate of 10 ºC/min. The acidolysis reaction of methyltriethoxysilane and phenyltriethoxysilane is a convenient and versatile method for the synthesis of new heat-resistant methylphenylsiloxane resins. In the course of the study, it was found that the resins obtained on the basis of organoalkoxysilanes are characterized by higher thermal and thermo-oxidative stability. It is shown that the modification methylphenylsiloxane resin dimethylsiloxane links in the main chain elementlocalname fragments of ≡Si-O-Element-O-Si≡, where element = B, Ti, Zr, Al increases its resistance to the level methylphenylsiloxane resin without dimethylsiloxane links.

Preparation of Chitin Whisker and Effect to Crystallization of Polylactide

The aim of this study was to investigate the effect of chitin whisker (CW) to the crystallization of polylactide (PLA) nanocomposite films. CW which obtained from acidolysis reaction was compounded with PLA pellets into nanocomposite films by cast film extrusion. The morphology and crystallinity of CW were observed by TEM and XRD, illustrated that the dimension of whisker was affected by hydrolysis time. Increasing of hydrolysis time, the length of whisker was more regular with narrower distribution. Moreover, the crystallinity of whisker was obviously increased after acid hydrolysis. The nanocomposite film showed rough surface compared to pure PLA film due to some agglomeration of nanoparticles. However, CW and PLA were well-mixed with no phase separation. The introduction of 0.1 phr of CW decrease cold-crystallization temperature (Tcc) from about 121 °C to 118 °C and also increase the degree of crystallinity around 10%. There was no difference of thermal transition temperature between pure PLA and nanocomposite films with the addition of CW more than 0.1 phr which inspected by DSC. Despite the transition temperature express insignificantly different, the degree of crystallinity of nanocomposite was increase, indicating that chitin whisker would induce the crystallinity of PLA.

Technological Study of Titanium Slag Production from Titanium-Bearing Blast Furnace Slag

Titanium-bearing blast furnace slag in which TiO2 content reaches to 20%~23% is a kind of precious secondary resource. The research utilizes the stable characteristic of TiO2 in hydrochloric acid to digest acid-soluble matters in slag. Titanium-bearing slag is obtained after solid-liquid separation process. The optimum acidolysis reaction condition can be known through analysis of raw material granularity, acid-slag ratio, reaction temperature and effect caused by reaction time on TiO2 content in slag. XRD image analysis can prove that the chemical compounds of Al、Mg、Fe are totally acid-thinned and TiO2 content in slag reaches to above 40%. This technology provides a valuable new way for the comprehensive utilization of titanium-bearing Slag.