The difference between ortho phthalic anhydride and Nai method

As important raw materials in organic chemical industry, o-phthalic anhydride (phthalic anhydride) and Naifa (para-hydroxyl isomer of phthalic acid) play different roles in practical application because of their differences in chemical structure and properties. In this paper, the differences and connections between the two will be analyzed in depth from the aspects of structure, chemical properties, production process and application fields.

1. structure and chemical properties of the difference

1. Structural characteristics

The structure of ortho phthalic anhydride is symmetrical, and the two carboxylic acid anhydride groups in the molecule are para-connected, showing a planar structure with high molecular symmetry. The molecular weight and structural complexity of Nye's law are different due to the different positions of hydroxyl groups and the asymmetric molecular structure.

with both physical properties

The melting point of ortho-phthalic anhydride is high, about 231 ° C., and has good stability, but it is easy to decompose at high temperature. The melting point of Naifa is lower, about 166°C, but it is more stable at high temperatures.

2. Chemical properties

Ortho phthalic anhydride has strong acidity, strong water absorption, low pH value, and is often used in chemical reactions under acidic conditions. However, the acidity of the Naifa is weak and the pH value is high, so it is often used in the reaction under neutral or alkaline conditions. This difference in pH value makes the use of the two scenarios significantly different.

2. production process and manufacturing method

1. Preparation method

The preparation of ortho-phthalic anhydride usually uses the traditional anhydride preparation method, the process is relatively simple, but the production efficiency is low. The preparation of the Nai method uses modern chemical synthesis methods, through multi-step reaction synthesis, production efficiency and product quality have been significantly improved.

2. Production equipment

The production of ortho-phthalic anhydride mostly uses chemical equipment in the 15th century, and the production process is relatively cumbersome and vulnerable to environmental factors. The production of Naifa uses automated production equipment from the late 1980 s and 1990 s, making the production process more efficient and more tightly controlled.

3. application field

1. Ortho phthalic anhydride application

Because of its high acidity, o-phthalic anhydride is widely used in the synthesis of organic acids, such as the manufacture of organic chlorine compounds and biodegradable materials. It has important application value in pharmaceutical, fine chemical and environmental protection materials.

2. Nai method of application

Because of its neutral pH value and good stability, Nafa is used as a preparation of neutral acid, which is used in the field of fine chemicals and biopharmaceuticals. In the synthesis of pharmaceutical intermediates and the extraction of bioactive substances, the performance of Naifa is particularly prominent.

4. environmental protection and safety factors

1. Environmental performance

Compared with o-phthalic anhydride, Naifa produces less harmful substances in the production process and has less impact on the environment. However, due to its flammable and explosive nature, it still needs to be strictly controlled when used.

2. Safety

Ortho phthalic anhydride because of its high acidity, the use of special attention to protection, avoid contact with the skin and eyes. The neutrality of Naifa makes it practical, but it still needs to wear protective equipment during operation to prevent accidents.

5. summary

As two forms of phthalic acid, o-phthalic anhydride and Naifa have significant differences in structure, chemical properties, production process and application fields. The choice of raw materials depends on the specific process requirements and application requirements. In the future, with the continuous advancement of chemical technology, more efficient and environmentally friendly production methods and applications will gradually expand, and promote the development of the co-integration of adjacent phthalic anhydride and Naifa.