In the process of synthesizing polysilazane, there are various ways to avoid side reactions:
Strictly control the reaction conditions
Temperature control: Accurately control the reaction temperature within an appropriate range, as different synthesis reactions have their corresponding optimal temperature ranges. For example, when preparing polysilazane by reacting silicon halides with ammonia, excessive temperature may cause additional reactions such as decomposition of reactants, resulting in unwanted small molecule products; However, if the temperature is too low, it may lead to a slow reaction rate, incomplete reaction, and increase the risk of subsequent side reactions. So it is necessary to determine the accurate and suitable temperature through multiple experiments based on the specific reaction system, and use high-precision temperature control equipment to maintain a stable temperature environment.
Pressure regulation: For reactions that require specific pressures, pressure parameters should be reasonably set and strictly controlled. For example, in some high-temperature and high-pressure synthesis processes, improper pressure may change the equilibrium direction of the reaction and promote the occurrence of side reactions. Accurately controlling the pressure to ensure the smooth progress of the main reaction can effectively avoid side reactions caused by abnormal pressure.
Atmosphere creation: It is crucial to maintain the reaction in an inert atmosphere (such as high-purity nitrogen, argon, etc.). Impurities such as oxygen and moisture in the air can easily react with reactants or products, generating by-products. The silicon nitrogen bond in polysilazane is sensitive to moisture. Once mixed with air, contact between moisture and it can trigger hydrolysis reactions, damaging the structure of the product. So it is necessary to continuously and stably introduce inert gas into the reaction vessel to maintain a good oxygen free and water free reaction environment.
Ensure the high quality of raw materials
High purity requirement: The selection of high-purity raw materials is the basis, such as silicon halides, ammonia or amines, silicon hydride compounds, etc. The higher the purity of the raw materials, the less impurities they contain, and the lower the possibility of side reactions. For example, if the raw material contains trace amounts of metal ion impurities, it may catalyze some unexpected side reactions. Therefore, it is necessary to purchase raw materials with a purity of 99.9% or higher as much as possible to reduce the risk of side reactions from the source.
Raw material pretreatment: For some raw materials that are prone to moisture absorption and contain impurities, pretreatment is required before use. For example, for some silicon containing monomers, water and impurities can be removed through vacuum distillation, vacuum drying, and other methods to ensure that they participate in the reaction in a pure state and avoid side reactions caused by impurities carried by the raw materials themselves.
Reasonable selection and use of catalysts
High selectivity catalyst: Select catalysts with high selectivity to accurately catalyze the main reaction while minimizing the catalytic effect on other side reactions. For example, in the synthesis of polysilazane involving hydrosilylation reactions, selecting appropriate transition metal catalysts (such as platinum based catalysts, etc.) can accelerate the main reaction rate while suppressing possible side reactions such as isomerization and over addition, guiding the reaction towards the direction of producing the target polysilazane product.
Accurate control of dosage: Accurately controlling the dosage of catalyst is also crucial, as excessive or insufficient catalyst dosage can lead to problems. Excessive usage may trigger unexpected catalytic reactions, leading to the occurrence of side reactions; Insufficient dosage may slow down the reaction rate, prolong the reaction time, and increase the likelihood of side reactions occurring. To determine the optimal range of catalyst dosage in this reaction system through preliminary small-scale experiments, and strictly operate according to this dosage.
Optimize reaction process
Optimization of feeding method: Adopt scientifically reasonable feeding methods, such as batch feeding, slow drip feeding, etc. For example, in the reaction of slowly adding ammonia dropwise to a silicon halide solution, if a large amount of ammonia is added at once, it may cause severe side reactions due to the high concentration of local reactants. By slowly adding, the reactants can be kept at a relatively uniform and appropriate concentration in the reaction vessel, and the reaction can proceed smoothly, effectively avoiding the occurrence of side reactions.
Reaction time control: Accurately grasp the reaction time and avoid excessively long or short reaction times. If the time is too long, the product may undergo further side reactions such as decomposition and polymerization; If the time is too short, the reaction may not be complete, and unreacted raw materials may also participate in the generation of new side reactions in the subsequent process. Based on the specific reaction system, the optimal reaction time that can ensure complete reaction and minimize side reactions should be explored through experiments, and the reaction should be terminated strictly according to this time.
Standardize reaction equipment and operating procedures
Equipment cleaning and maintenance: Ensure that the reaction equipment is clean, free of impurities, and has good sealing. Impurities remaining on the inner wall of the equipment may mix into the reaction system, causing side reactions; Poor sealing can easily allow external air to enter, bringing in unfavorable factors such as oxygen and moisture. Regularly clean and dry the reaction equipment, and check its sealing performance to ensure that the reaction takes place in a pure and stable environment.
Standardization of operating procedures: Develop strict and standardized operating procedures, and require operators to strictly follow them. Any non-standard operational behavior, such as incorrect feeding sequence, untimely temperature adjustment, etc., may lead to uncontrolled reactions and subsequently trigger side reactions. Operators need to undergo professional training, familiarize themselves with each operation step and precautions, and follow standard procedures for synthesis operations.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150K.    
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.