Background and overview[1]
Diphenyl glycolic acid, also known as diphenyl glycolic acid, is a white monoclinic needle crystal with a bitter taste. It melts into dark red at high temperatures. It is easily soluble in hot water, ethanol, and ether, and is slightly soluble in cold water and acetone. Its potassium salt is easily soluble in water, and the solution is red; its lead salt is an amorphous precipitate, which turns into a dark red solution when heated.
Preparation[1]
The benzoin produced in the first step of the reaction first generates diphenylethylenedione under the oxidation of oxidant NaBrO3, and then diphenylethylenedione generates the sodium salt of diphenylglycolic acid under the action of sodium hydroxide, which is called diphenylglycolic acid. It is the rearrangement of diphenyl glycolic acid (Figure 1). The formation of stable carboxylate salts is the driving force of the reaction. Once the carboxylate is generated, diphenylglycolic acid is generated after acidification.
The infrared spectrum of diphenylglycolic acid shows that: 3398.3cm-1 is the O—H stretching vibration, 2916.2 cm-1 is the C—H stretching vibration, 1720.4 cm-1 is the C =O stretching vibration, 1055.0 cm-1 is the C—O symmetric stretching vibration, 771.1cm-1 and 698.2cm -1 is the characteristic absorption of single substitution on the benzene ring; in addition, single bond stretching and various bending vibrations appear in the fingerprint area. See Figure 5.
Apply [2-3]
1. Used to prepare highly hydrophobic biodegradable soy protein plastics
CN200810046798.8 provides a method for preparing highly hydrophobic biodegradable soybean protein plastic. It uses isolated soybean protein as raw material, adds thiodiglycol and diphenyl glycolic acid, and prepares soybean protein plastic by hot pressing method. , the operation process is simple, and the prepared soy protein plastic is highly hydrophobic and biodegradable. The technical solution adopted to achieve the purpose of the present invention is: a preparation method of a highly hydrophobic biodegradable soy protein plastic includes the following steps: first mix soy protein isolate and thiodiglycol for 10 to 30 minutes, and then add diphenyl After adding glycolic acid, mix and stir for 10 to 30 minutes, and then hot-press the resulting mixture at 150 to 160°C and 10 to 20 MPa for 5 to 20 minutes to prepare soy protein plastic.
The dosage of thiodiglycol is 20-30wt% of the soybean protein isolate. The dosage of diphenyl glycolic acid is 0 to 20 wt% of soybean protein isolate, and 0 to 20 wt% does not include 0. The prepared soy protein plastic can be used as covering material, packaging material or disposable container material in the fields of agriculture, chemical industry, food or environment. Compared with the existing technology, the innovations of the present invention are as follows: the plasticizer used in the present invention is thiodiglycol, which is the hydrolyzate of mustard gas [(ClC2H4)2S], and has low cost and less than traditional glycerol. A hydrogen bond is more conducive to improving the water resistance of soy protein plastics, and due to the presence of sulfur-containing groups, the service life of soy protein plastics is extended. The present invention obtains 100% water-resistant biodegradable soy protein plastic by adding diphenyl glycolic acid.
2. Can be used for ultrasound-assisted preparation of vaterite calcium carbonate nano-assembly structures
Calcium carbonate is widely used in rubber, plastics, coatings, papermaking, inks, glue dots, sealants and other industries, and can also be used in toothpaste, food, medicine, packaging materials, building materials, chemical fiber and other industries. The crystal forms of calcium carbonate include three types: calcite, acrylic resin stone, and vaterite. Among them, calcite has the most stable structure. Both aragonite and vaterite are unstable, and vaterite is difficult to stabilize. Nano calcium carbonate has small particle size and large specific surface area. Compared with ordinary calcium carbonate, it has excellent performance. Nano-calcium carbonate with a particle size between 10-100nm has a reinforcing effect on rubber, plastics, etc.; while ultra-fine calcium carbonate with a particle size of 5-20nm has a reinforcing effect comparable to that of white carbon black. Nanoparticles can be used as building blocks for various superstructure materials to prepare assembly structures with different secondary structures “bottom-up”. Self-assembly systems with regular and different structures can enable certain physical and chemical interactions between nanoparticles, thereby enabling the product to have complex, diverse, and optimized functionality.
However, most of the nano-calcium carbonates prepared in the existing technology are micron or sub-micron in size. It is difficult to obtain ultra-small-sized nano-calcium carbonate with stable vaterite crystal form and assemble it into nano-calcium carbonate assembly. structure. The technical solution of the present invention is to overcome the shortcomings of the existing technology and propose a calcium carbonate nano-assembly structure for preparing vaterite. The invention proposes an ultrasound-assisted method for preparing vaterite calcium carbonate nano-assembly structures, which includes the following steps:
1) Prepare solution a: Dissolve the calcium salt in deionized water, heat to 60-80°C, add diphenyl glycolic acid, and stir evenly;
2) Prepare solution b: Dissolve sodium carbonate, ammonium carbonate or ammonium bicarbonate in deionized water;
3) Dissolve polyethylene glycol in toluene, add solution a, stir at 60-80°C for 1 hour, add solution b under ultrasound, react with ultrasound for 10-20 minutes, cool to 40-50°C, and stir for 1 hour;
4) Collect the product, centrifuge, wash and dry to obtain a vaterite calcium carbonate nano-assembly structure.
This method uses diphenyl glycolic acid as the crystal form control agent and morphology control agent, and uses ultrasound to initiate the interface reaction of the reactants colliding between the organic phase and the aqueous phase droplets, thereby obtaining a stable vaterite phase. Triangular sheet-shaped calcium carbonate nanoparticles control the assembly of calcium carbonate nanoparticles by reducing the solubility of diphenylglycolic acid, thereby obtaining a spherical assembly with an assembly size of approximately 1500-3000nm.
Main reference materials
[1] Zhao Sanhu, Zhao Minggen. Synthesis and characterization of diphenylglycolic acid catalyzed by vitamin B_1 tablets [J]. Journal of Gansu United University (Natural Science Edition), 2009, 23(06): 53-56.
[2]CN200810046798.8 Preparation method and use of highly hydrophobic biodegradable soy protein plastic
[3] CN201710485979.X A method for ultrasonic-assisted preparation of vaterite calcium carbonate nano-assembly structure
