5 results about "Solubility equilibrium" patented technology

The present application belongs to the technical field of crystalline compounds, and particularly relates to a preparation method of small-particle-size tigositabine crystal form A. The method comprises dissolving tigositabine crude product in an acidic mixed solvent (pH 2-3) containing a surfactant, removing impurities by hot filtration after constant-temperature stirring, transferring the filtrate into a crystallizer, pressurizing and cooling, slowly releasing pressure, adding an alkali solution to adjust to neutrality, and obtaining the product after low-temperature aging, filtration and drying. The present application effectively inhibits crystal grain agglomeration and growth by means of synergistic methods such as surfactant regulation, controllable nucleation by pressurizing and cooling, slow pressure release and mild alkali adjustment crystallization, and small-particle-size crystal form A with a Dv(90) of 7.46-8.97 μm is prepared. The product yield reaches 85.5%-88.0%, the dissolution rate in water is significantly better than that of the original research and the product of the comparative example, and the dissolution equilibrium can be basically reached in 30 min, thus solving the technical pain points of large crystal size and slow dissolution in the prior art, and the present application can be widely used in the research and production of tigositabine preparations.

The invention discloses a high-temperature and high-pressure natural gas solubility determination and isotope fractionation simulation experiment device and method. The device comprises a gas supply module, a liquid supply module, an integrated reaction kettle, a vacuum module, an independent double-path gas collection module, a test analysis module and a computer control system. The method comprises the following steps: injecting a solution and natural gas into a reaction kettle until dissolution equilibrium, and introducing a state equation to directly calculate theoretical dissolved gas volume and solubility; independently collecting residual free gas in an equilibrium state and overall desolventized gas, determining isotopes, and calculating a thermodynamic equilibrium fractionation coefficient in the dissolution process; natural gas is induced to be continuously desolventized, instantaneous desolventized gas is collected in sections, isotopes are measured, and solvokinetic fractionation parameters are calculated in combination with a Rayleigh model. The whole process is completed in situ in the same kettle body, fluid transfer errors are thoroughly eliminated, and a reliable evaluation means is provided for deep natural gas reservoir forming simulation.

This invention discloses a method for the directional preparation of high-purity pentazole energetic eutectic based on a ternary phase diagram. The method first determines the solubility of the pentazole salt and the eutectic ligand in a selected solvent. Then, a series of pentazole salt solutions of different concentrations are reacted with excess ligand. After reaching dissolution equilibrium, filtration and dilution are performed. High-performance liquid chromatography (HPLC) is used to determine the concentration of each component, and a ternary phase diagram of the pentazole salt-eutectic ligand-solvent system is constructed accordingly, ultimately determining the formation region of the eutectic and the optimal feed ratio. Under the optimal conditions, the pentazole salt and ligand are mixed and stirred in a specific ratio, and then filtered to obtain the high-purity pentazole eutectic product. This method is simple to operate, has a short cycle time, low cost, good reproducibility, and produces high-purity products, providing an efficient and reliable preparation route for the rapid and controllable synthesis of pentazole energetic eutectic.

The invention relates to a gas-liquid saturated solution phase equilibrium and viscosity integrated measurement device, which comprises a constant temperature environment space, a built-in gas cavity and an equilibrium kettle and is used for realizing dissolution equilibrium of solute gas and a solvent; the gas filling system is used for conveying solute gas to the device; the viscosity measuring system is used for measuring the viscosity of the saturated liquid through two capillary tubes which can be connected in series and in parallel; the working medium circulating system is used for driving saturated liquid to flow; the density measuring system is used for measuring the density of saturated liquid; the temperature and pressure measuring system is used for monitoring pressure and temperature parameters in the device; the temperature control system is used for controlling the temperature in the device; the magnetic stirring system is used for accelerating gas-liquid two-phase balance in the balance kettle; the vacuum treatment system is used for vacuumizing the device; the solubility measuring system is used for collecting a saturated liquid sample and calculating the solubility; and the data acquisition and processing system is used for recording and processing related measurement data in real time. The device is convenient to use and accurate and efficient in measurement.

The invention discloses a rapid determination method of ammonia nitrogen in a complex matrix sample, which comprises the following steps: pre-treating the complex matrix sample to be determined: weighing the sample, placing the sample in a headspace bottle, adding ammonia-free water, adjusting the pH to neutralize, adding a small amount of high-concentration non-volatile inorganic strong alkali solution, covering and sealing, and uniformly mixing to obtain a sample solution; the volume of the sample solution accounts for 40-60% of the total volume of the headspace bottle; after the sample solution reaches escape-dissolution equilibrium, sample gas is extracted by using pretreatment equipment, and the sample gas is detected according to preset chromatographic conditions in cooperation with a gas chromatograph and a detector; preparing a standard stock solution containing ammonium ions, and establishing a standard curve and a peak area of a standard sample point; and processing data according to a sample detection result, and judging whether the ammonia nitrogen content in the sample is qualified or not. According to the method, the target object can be rapidly measured only by additionally adding a chemical reagent into a detection system, and the anti-interference capability is high.