Application of Methyltetrahydrophthalic Anhydride_Kain Industrial Additives

Background and overview^[1]

Methyltetrahydrophthalic anhydride, also known as methyltetrahydrophthalic anhydride, is a light yellow transparent oily liquid. It is an important intermediate in electronic information materials, medicines, pesticides, resins, and defense industries. It can also be used in coatings. , plasticizers, pesticides and other industries. Methylene tetrahydrophthalic anhydride is mainly produced by Diels-Alder reaction of mixed C5 and maleic anhydride. The main components of mixed C5 are piperylene and isoprene (mass fraction about 50%), pentene-1, pentene-2, n-pentane and isopentane. The main reactions of mixing C5 and maleic anhydride are the reaction of piperylene with maleic anhydride and the reaction of isoprene with maleic anhydride.

Domestic production of methyltetrahydrophthalic anhydride uses a batch production process. This process has many shortcomings, such as time-consuming and labor-intensive operation, unstable system, slow reaction when the concentration of reactants decreases in the later stage of the reaction, thereby increasing the reaction time. Different batches There are differences in products, insufficient production capacity, etc. In recent years, as the motor, electronics, and electrical appliance industries have continuously improved their requirements for insulation performance and reliability, the application of this type of curing agent has developed rapidly, and the market demand has become larger and larger. The shortcomings of the intermittent production process are particularly obvious in this context.

Structure

Apply^[1-3]

Methyltetrahydrophthalic anhydride (MTHPA) is an important intermediate in electronic information materials, medicines, pesticides, resins, and defense industries. It has the characteristics of low melting point, low toxicity, low volatility, etc. It is easy to use, has high reactivity with epoxy resin and good miscibility. The epoxy resin cured product using this curing agent has excellent electrical insulation properties and mechanical properties. In recent years, with the continuous improvement of insulation performance reliability requirements in the motor, electronics, and electrical appliance industries, the application of this type of curing agent has developed rapidly and has good market prospects. Examples of its application are as follows:

1) For preparing a heat-resistant and toughened methyltetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, heat-resistant acid anhydride and toughening agent are heated and reacted in the presence of an acidic catalyst. The weight ratio of tetrahydrophthalic anhydride, heat-resistant acid anhydride, toughening agent and catalyst is 1:0.06~0.5:0.10~0.40:0.008~0.05. The reaction temperature is between 80~200℃. After the heating reaction, methyltetrahydrophthalic anhydride is obtained. The liquid crude product is then put into the flash kettle. The temperature of the flash kettle is between 170 and 240°C, and the flash is carried out under the condition that the vacuum degree is gauge pressure minus 0.070 to 0.095MPa. Steam and refine to obtain modified heat-resistant and toughened methyltetrahydrophthalic anhydride. After modification, the glass transition temperature of the modified methyltetrahydrophthalic anhydride and epoxy resin cured product can reach 135~150℃, and the impact strength is 16~25KJ/M2.

2) Preparing C5 petroleum resin from methyltetrahydrophthalic anhydride production waste liquid, including: (1) separating the cis piperylene material A obtained by removing gum from the methyltetrahydrophthalic anhydride production waste liquid, and Separate and remove dicyclopentadiene from the cracked C5 fraction to obtain decyclic C5 material B; (2) Feed materials A and B in a weight ratio of 1:0.1-5, and catalyze them in C5 light oil under the catalysis of aluminum trichloride catalyst. Intermittent cationic polymerization is carried out in a solvent; (3) After the polymerization reaction, the catalyst is removed using three-stage continuous water washing to obtain C5 petroleum resin. The C5 petroleum resin coating prepared by the invention has light color, high softening point and stable quality index, and is specially used for road markings. This method utilizes the waste liquid produced by methyltetrahydrophthalic anhydride, improves the utilization value of the waste liquid, and adopts continuous water washing. The process has been automated, improving washing efficiency while reducing water and material losses.

Preparation^[1]

Synthesize methyltetrahydrophthalic anhydride using a gaseous mixture of C5 and maleic anhydride as raw material: methyltetrahydrophthalic anhydride:

1) Intermittent reaction experimental method

Prepare a certain amount of 25% maleic anhydride-methyltetrahydrophthalic anhydride solution, add an appropriate amount of polymerization inhibitor, take 80mL of the prepared solution and add it to the maleic anhydride solution storage bottle, take 41mL of the mixed C5 liquid and add C5 In the storage bottle (the ratio of the active components in C5 to maleic anhydride is 1.1:1), keep the water temperature stable at 44°C (the boiling point of C5 at normal temperature) in the constant temperature water tank, and control the dripping of C5 by adjusting the knob. Accelerate, add dropwise at the rate of ld/3s, ld/4S and ld/5S. C5 is added dropwise into the vaporization bottle to quickly vaporize and flow into the reaction bottle to react with the maleic anhydride solution (C5 gas velocity is measured in liquid volume) , the experiment mainly examines the feed rate and �� of c5.To examine the effect of temperature on the reaction, record the temperature in the reaction bottle every 15 minutes after the experiment starts, and take samples for analysis.

2) Continuous reaction experimental method

Prepare a certain amount of 25% maleic anhydride solution in methyl tetrahydrophthalic anhydride, add an appropriate amount of polymerization inhibitor, add the prepared maleic anhydride solution into a storage bottle, and add a sufficient amount of mixed C5 liquid In the C5 storage bottle, the constant temperature water bath where the C5 vaporization bottle is located is kept at 44°C. The dripping speed of C5 and maleic anhydride is controlled by adjusting the knob to examine the impact of the feed ratio on the reaction (the feed ratio is the amount of C5 active component and Ratio of the amount of maleic anhydride), change the temperature of the No. 1 constant temperature water bath to examine the effect of temperature. Record the temperature in the reaction bottle every 15 minutes after the start of the experiment, and take samples for analysis.