33results about How to "Avoid degradation reactions" patented technology

The invention belongs to the technical field of chemistry, and in particular relates to a method for synthesizing azithromycin rearrangement impurity lactam. Its main steps are: (3R,4R,5S,6R,9R,10S,11S,12R,13R,15R,Z)‑12‑[[3,4,6‑trideoxy‑3‑(dimethylamino)‑ β-D-wood-hexyranosyl]oxy]-6-ethyl-4,5-dihydroxy-10-[(2,6-dideoxy-3-C-methyl-3-O-methyl yl-a-L-nucleo-hexyranosyl)oxy]-3,5,9,11,13,15-hexamethyl-7,16-dioxo-2-azabicyclo[11.2.1] Hexadecane-1-en-8-one (compound Ⅱ) undergoes acidification and alkalinization rearrangement, and after purification, the rearranged impurity lactam with a purity >99.5% is obtained. The synthesized high-purity azithromycin rearrangement impurity lactam is used as the impurity standard for finished product detection, which is conducive to strengthening the positioning and characterization of the impurity and improving the quality control of azithromycin API.

The invention discloses a structural silicone adhesive with low modulus and high volume resistivity. The structural silicone adhesive is composed of a component A and a component B according to a volume ratio of 10: 1, wherein the component A is composed of hydroxyl-terminated polymethylsiloxane, a plasticizer and a reinforcing filling material; and the component B is composed of methyl-terminatedpolydimethylsiloxane, pigment carbon black, a silane coupling agent, a chain extender, an active hydrogen sealing agent, a cross-linking agent, a catalyst, an antioxidant, a light stabilizer and a deep curing agent. The structural silicone adhesive with low modulus and high volume resistivity provided by the invention improves the volume resistivity of a conventional structural adhesive from 1015omega.cm to 1016 omega.cm, increases an order of magnitude in the volume resistivity, is applicable to structural assembly of a system with photovoltaic voltage classes of 1500 V, 2000 V and even 3000 V, specifically to structural adhesion assembly of places with high requirements on insulation, such as thin film assemblies, and exerts an effect of structural adhesion.

The invention discloses a disinfectant. The disinfectant is solution prepared by mixing A solution and B solution, wherein the A solution is prepared by mixing 15 to 20 mass percent solution of sodium chlorite and the solution of stabilizer, while the B solution is the mixed aqueous solution of citric acid and oxalic acid. The solution of stabilizer is 5 to 10 mass percent solution uniformly prepared from dianine sulfate, triethanolamine, ammonium persulfate and alchlor, and the mass ratio of the dianine sulfate to the triethanolamine to the ammonium persulfate to the alchlor is 1: 0.5-1.5: 0.5-1: 1.5-2.5. The volume of the solution of stabilizer is 2 to 5 percent based on the total volume of the A solution. The mass ratio of the citric acid to the oxalic acid is 1: 2-4, and the content of the B solution is 40 to 50 mass percent. The used volume ratio of the A solution to the B solution is 1-4: 1. The disinfectant has the advantages that: the medicinal performance is stable; disinfectant damages to an environment and human bodies are avoided in the use and production processes of the disinfectant; and apparatus and equipment are not corroded during the production.

The invention relates to a methylergometrine maleate injection and a preparation method thereof and belongs to the technical field of pharmaceutical preparations. The methylergometrine maleate injection comprises isoosmotic adjusting agent, buffer agent, antioxygen, metal ion complexing agent, analgesic and the like. Due to high stability of methylergometrine maleate and prescription ratio which is selected precisely and verified repeatedly, the methylergometrine maleate injection has more remarkable stability. The preparation method of the methylergometrine maleate injection is easy, in other words, the methylergometrine maleate injection can be produced by a conventional preparation method without any special equipment. Therefore advantages such as industrialization feasibility, high production efficiency, sterility guarantee, low adverse effect, controllable quality and excellent stability are achieved.

Application of binaphthol derivatives in living radical photopolymerization. The invention relates to the field of organic photocatalyst catalyzed controllable active free radical polymerization, in particular to 1,1'-bi-2,2'-naphthol derivatives used as organic photocatalysts to undergo active controllable free radical photopolymerization under visible light organic catalytic system. The present invention uses BINOL-based polymers as organic photoredox catalysts, which can achieve rapid reversible balance between dormant species and active chains, making the polymerization reaction controllable, and can prepare homopolymers with controllable molecular weight and low polydispersity. At the same time as compound and block copolymer, it also provides a new application method for BINOL organic polymers in organic photocatalytic active radical polymerization; the organic photocatalytic system involved in the present invention has high efficiency, low cost, easy operation, The prepared polymer has the characteristics of controllable molecular weight and narrow polydispersity, which conforms to the production concept of environment-friendly green production.

The invention discloses a method for manufacturing a super-barrier multi-layer hollow container, comprising: a blow molding process, in which a preform made of resin material is injected into the preform with a first air pressure P1 Blowing nitrogen to form a hollow body with a first volume; mixing blow molding process, reducing the air pressure to the second air pressure P2, and blowing fluorine gas into the hollow body with a third air pressure P3 to form a hollow body with a second volume. Embryo body, wherein, P3 is greater than P1; cycle blow molding process, reduce the air pressure to the fourth air pressure P4, blow nitrogen into the hollow body with the fifth air pressure P5, wherein, P5 is less than P3, repeat this step until After the blowing time is over, the hollow container of a predetermined shape is formed, and the outer wall of the hollow container is at least partially attached to the cavity wall of the extrusion blow mold. The invention can make the barrier property of the produced hollow container stronger, expand its application range, and greatly improve the economic benefit while improving the production efficiency.

A method for directly preparing 2,5-dimethyloltetrahydrofuran from fructose, the method is in a water / oil two-phase system, under the condition of 0.5-10MPa H2, 80-180°C, under the action of a catalyst for 0.5-16h Direct one-step conversion of fructose to 2,5‑dimethyloltetrahydrofuran. The highest selectivity of 2,5-dimethyloltetrahydrofuran is 72%, and the highest yield is 56%.

The invention belongs to the technical field of chemistry, and particularly relates to a synthetic method of an azithromycin rearrangement impurity R. The method mainly comprises the steps that (3R,4R,5S,6R,9R,10S,11S,12R,13R,15R,Z)-12-[[3,4,6-trideoxy-3-(dimethylamino)-beta-D-wood-pyranose group]oxygen]-6-ethyl-4,5-dihydroxyl-10-[(2,6-dideoxy-3-C-methyl-a-L-nuclear-pyranose group)oxygen]-3,5,9,11,13,15-hexamethyl-7,16-dioxy-2-azabicyclo[11.2.1]cetane-1-alkene-8-ketone(compound III) is subjected to acidification rearrangement, and after refining is conducted, the rearrangement impurity R withthe purity being 99.5% or above is obtained. The synthesized high-purity azithromycin rearrangement impurity R serves as an impurity standard substance of finished production detection, locating and qualification on the impurity are enhanced conveniently, and quality control over azithromycin active pharmaceutical ingredient is improved.

The invention discloses a moisture-resistant and heat-resistant high-strength silicone structural adhesive special for photovoltaic assemblies. The moisture-resistant and heat-resistant high-strengthsilicone structural adhesive special for the photovoltaic assemblies consists of an A component and a B component according to a volume ratio of 10:1, wherein the A component consists of hydroxyl-terminated polydimethylsiloxane, a thixotropic agent, a reinforcing filler, a heat-resistant filler and a plasticizer; and the B component consists of methyl-terminated polydimethylsiloxane, pigment carbon black, a silane coupling agent, an active hydrogen blocking agent, a crosslinker , a catalyst, an antioxidant, a light stabilizer, and a deep curing agent. According to the moisture-resistant and heat-resistant high-strength silicone structural adhesive special for the photovoltaic assemblies, the problem that currently strength of a silicone structural adhesive decreases after damp-heat aging is solved; and the moisture-resistant and heat-resistant high-strength silicone structural adhesive special for the photovoltaic assemblies is applicable to the fields of structural bonding of double glass assembly back tracks, and between hanging buckles and glass, and bonding and sealing of photovoltaic assembly frames, and junction boxes, etc.; and the structural adhesive has high strength, excellent heat and humidity resistance and adhesion, and can play a structural adhesive role.