Chemical Intermediate

There have been considerable efforts to produce renewable polymers from biomass. Poly(ethylene terephthalate) (PET) is one of the most versatile bulk materials used in our daily lives. Recent advances in the new catalytic process for conversion of biomass have allowed us to design more technically effective and cheaper methods for the synthesis of green PET monomers. This review analyses recent advances in the synthesis of PET monomers from biomass. Different routes for ethylene glycol (EG) and purified terephthalic acid (PTA) synthesis are systematically summarized. The advantages and drawbacks of each route are discussed in terms of feedstock, reaction pathway, catalyst, economic evaluation and technology status, trying to provide some state-of-the-art information on green PET monomer synthesis. Finally, an outlook is presented to highlight the challenges, opportunities and on-going trends, which may serve as guidelines for designing novel synthetic routes to green polymers from fundamental science to practical use.

The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC–5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33 ± 6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03 ± 0.01%) and the highest tissue adherence (75.67 ± 1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®.

The invention relates to a method for synthesizing 2-methoxy-4-cyano benzaldehyde which servers as an important medicinal intermediate. The method comprises the following steps: causing 3-methoxy-4-methyl benzoate to react with thionyl chloride react under the heating condition to generate 3-methoxy-4-methyl benzoyl chloride; causing the 3-methoxy-4-methyl benzoyl chloride to react with aqueous ammonia to generate 3-methoxy-4-methyl benzoyl amide; dehydrating the 3-methoxy-4-methyl benzoyl amide to generate 3-methoxy-4-methyl benzonitrile; brominating the 3-methoxy-4-methyl benzonitrile by N-bromosuccinimide (NBS) to generate 3-methoxy-4-benzylene bromide benzonitrile; and hydrolyzing the 3-methoxy-4-benzylene bromide benzonitrile to obtain the target product of 2-methoxy-4-cyano benzaldehyde. The method provided by the invention has the outstanding advantages that the reaction condition is mild, the reactions are rapid, the process is simple, and the operation is easy, thereby being suitable for industrial production.

Mushroom tyrosinase (EC 1.14.18.1), a copper containing oxidase, catalyzes both the hydroxylation of tyrosine into o-diphenols and the oxidation of o-diphenols into o-quinones. In the current study, the effects of 4-cyanobenzaldehyde and 4-cyanobenzoic acid on the monophenolase and diphenolase activities of mushroom tyrosinase have been studied. The results show that 4-cyanobenzaldehyde and 4-cyanobenzoic acid can inhibit both the monophenolase activity and the diphenolase activity of mushroom tyrosinase. The lag phase of tyrosine oxidation catalyzed by the enzyme was obviously lengthened, and the steady-state activity of the enzyme decreased sharply. 1.0 mM 4-cyanobenzaldehyde and 4-cyanobenzoic acid can lengthen the lag phase from 78 s to 134 and 115 s, respectively. Both 4-cyanobenzaldehyde and 4-cyanobenzoic acid can lead to reversible inhibition of the enzyme. The IC50 values of 4-cyanobenzaldehyde and 4-cyanobenzoic acid were estimated as 0.62 and 2.45 mM for monophenolase and as 0.72 and 1.40 mM for diphenolase, respectively. A kinetic analysis shows that 4-cyanobenzaldehyde and 4-cyanobenzoic acid are mixed-type inhibitors for the diphenolase. The apparent inhibition constants for 4-cyanobenzaldehyde and 4-cyanobenzoic acid binding with both the free enzyme and the enzyme–substrate complex have been determined and compared.

The effect of primary, secondary and tertiary hexylamines as collectors for the reverse flotation of quartz from an artificial mixture with hematite (1:1 by weight) was investigated by varying the pH and the collector concentration. The results show that di-n-hexylamine (di-HAA) was the most selective collector for the reverse flotation of fine quartz from hematite. The adsorption isotherms of di-HAA on quartz and hematite show much lower “saturation” values than those of mono-HAA on quartz and hematite. The adsorption densities of di-HAA on hematite are apparently too small to obtain the surface hydrophobicity that is necessary for flotation, even if the concentration is increased up to 1·10−3 mol l−1.

Di-n-hexylamine was originally used to synthesize pure SAPO-31 as a structure directing agent (SDA) and the synthesized SAPO-31 crystals have some novel features. After loaded with Pt, it exhibits higher selectivity to isomerization compared with the results of SAPO-31 prepared by the regular method.