Application and Synthesis of 2-vinylpyridine

Application and synthesis of 2-vinylpyridine

Pyridine and its derivatives are important intermediates for the synthesis of pesticides and pharmaceuticals. As an important pyridine derivative, 2-vinylpyridine is mainly used in the synthesis of butylpyridine latex, cisplatin (silicosis treatment drug), paclitaxel hydrochloride (vasodilator), ion exchange resin, chemical film, etc.

Application of 2-vinylpyridine

2-vinylpyridine (2-VP) is a kind of fine chemical product with wide application, which can be used as a common carrier of polymer loading catalyst, intermediate of organic synthesis and monomer of polymer in functional polymer, surfactant, antistatic agent, coating, medicine and pesticide, etc. 2-VP is an important monomer for the synthesis of many kinds of polymers.

1.Rubber industry

Currently, the largest use of 2-vinylpyridine is copolymerization with styrene and others to produce butylpyridine latex. Butylphenyl pyridine latex (VPL for short) is a terpolymer emulsion made from butadiene, styrene and 2-vinylpyridine through emulsion polymerization. Due to the introduction of a very polar pyridine group within the molecule, it has a strong adhesive ability. It is mainly used for impregnating cord or cord fabric such as rayon, nylon, polyester, etc. It is widely used in rubber products such as high-strength tires, pressure-resistant hoses, transportation belts, hiking boots, etc. for aircraft and automobiles. Compared with natural latex or styrene butadiene latex, styrene butadiene latex can increase the adhesion strength of rayon cord bonded to rubber by 17%~67%, and the adhesion strength of nylon cord bonded to rubber by 43~122%. In recent years, with the rapid development of China's national economy, the production of rubber products, mainly tires, is large

2. Pharmaceutical industry

In the pharmaceutical industry, the use of styrene-2-vinylpyridine copolymer as a film coating material for tablets has many advantages and is gradually replacing the traditional sucrose coating material. This coating material can overcome the disadvantages of sugar coating such as easy moisture deterioration and cracking, and ensure the stability of tablets for a long time. In addition to synthetic coating materials, 2-vinylpyridine can also be used in the production of drugs such as cisplatin and pethidine hydrochloride in medicine.

3. Functional polymer materials

In the emerging molecular branding technology, 2-vinylpyridine as a functional monomer for non-covalent molecular branding chiral stationary phase chiral separation ability is better. Acrylamide can form strong hydrogen bonding with the amide group of amino acid derivatives, while the basic functional monomer 2-vinylpyridine forms strong ionic interaction with its carboxyl group. The synergistic effect of both makes the composite functional monomer acrylamide + 2-vinylpyridine have good branding effect for amino acid derivatives.

4. Electronic materials

2-vinylpyridine can get block copolymer after self-polymerization and reaction with polyethylene glycol and other substances, and then form complexes with other substances to make the cathode material of electrode, which can effectively reduce the internal resistance of all-solid-state lithium secondary battery and promote the transfer of lithium ion at the cathode and between the cathode and electrolyte to reduce the internal resistance of the battery.

Ligands in the form of complexes as catalyst carriers

2-Vinylpyridine can be polymerized with many substances to obtain polymer copolymers used as ligands for complexes in the field of catalysis. For example, the rare-earth polymer complexes synthesized from vinylpyridine have been widely studied recently, which can be used as catalysts and have special optical properties.

5. Pesticide industry

2-vinylpyridine is used to synthesize the herbicide paraquat, and it can also be used with methanol to synthesize the insecticide imidacloprid, etc. These pesticide products are the leading varieties of pesticides in the market now.

Synthesis method of 2-vinylpyridine

Addition reaction of acrylonitrile and acetylene in the presence of catalyst

The catalytic addition reaction between acrylonitrile and acetylene in the presence of organocobalt can produce 2-vinylpyridine, and the reaction equation is as follows.

2-Vinyl pyridine prepared by addition of acrylonitrile and acetylene.jpg

Decarboxylation of pyridyl acrylic acid

In 1983, Stoicescu Calin et al. from Romania proposed the decarboxylation of pyridinyl acrylic acid to synthesize vinyl pyridine. Pyridinyl acrylic acid, copper powder and hydroquinone were mixed together and refluxed in quinoline solvent under nitrogen atmosphere for 1.5h to obtain 65.7% of vinyl pyridine.

Preparation of 2-vinylpyridine by decarboxylation of pyridinyl acrylic acid.jpg

Dehydrogenation of ethylpyridine at high temperature

Preparation of 2-vinylpyridine by dehydrogenation of ethylpyridine at high temperature.jpg

Oxidative dehydrogenation of 2-ethylpyridine with chromium-niobium catalyst to obtain 2-vinylpyridine

The production of vinyl pyridine by dehydrogenation reaction of alkylpyridine in the presence of oxygen with V2Os /MgO and MoO3/Mg0 as catalysts has also been reported, but the selectivity of vinyl pyridine in this method is very low.

Methyl pyridine (MP) and formaldehyde as raw material, dehydration after addition or direct synthesis

Preparation of 2-vinylpyridine from methyl pyridine (MP) and formaldehyde.jpg

Properties of 2-vinylpyridine

2-vinylpyridine is transparent liquid at room temperature, volatile, colorless but with irritating odor, slightly soluble in water, soluble in acetone, benzene, very soluble in various organic solvents, such as chloroform, ethanol, ether. Its main physical properties are shown in Table 1-1.

The molecular structure of 2-vinylpyridine is similar to styrene, chemically active, easily denatured under light or heat, self-polymerization into a brown viscous liquid, often added to the appropriate amount of polymerization inhibitor 4-tert-butyl catechol in storage; is flammable, volatile vapor mixed with air, combustion and even explosion can occur when exposed to open flame; poor stability, decomposed into toxic nitrogen oxide gas under heat, so In the use and storage process should avoid direct contact with acid and alkali substances, strong oxidizing substances, to prevent contact with ultraviolet radiation, fire sources and free radical initiators, resulting in accidents. Thus, in the process of storage, the following three points should be noted:

• (1) Store in a cool, ventilated environment. Keep away from fire, static electricity, water and heat sources, and store separately from strong oxidizing substances, and never mix them.
• (2) Stored in a dark place, prevent light exposure, sealed storage. Do not use mechanical devices and equipment that can easily generate sparks and static electricity for transportation. Storage with emergency fire and explosion-proof facilities, as well as leak emergency treatment facilities and shelter materials;
• (3) The liquid is sealed in tightly sealed brown glass bottles and wrapped externally in wooden barrels or iron passages. Store in a dry, low-temperature environment with attention to ventilation, moisture and protection from direct light.

In addition, 2-vinylpyridine is a toxic and harmful chemical with tearing and irritation, and direct contact or accident will endanger human health, mainly in the following ways:

• (1) When used in the laboratory, brief exposure to specific concentrations of 2-vinylpyridine may cause inflammation of the eyes, nose and throat, and longer exposure may cause headache, nausea, nervousness, and anorexia.
• (2) Direct contact of liquid 2-vinylpyridine with the skin can cause a burning sensation, even with immediate skin rinsing treatment, followed by relatively severe burns, with the affected area exhibiting a reddish-brown burn mark that disappears over a period of about one month;
• (3) 2-Vinyl pyridine at a concentration of 0.5 ppm or more produces a very unpleasant and disgusting odor, which may cause acute symptoms and allergies even when the concentration is low and the odor is small and tolerable. Common treatment methods:
• (1) Inhalation: ensure unobstructed airway, artificial respiration if necessary, seek medical attention in serious cases, observe and note the phenomenon of respiratory failure, and give oxygen infusion 10~15L/min if needed;
• (2) eye contamination: immediately flush with water, and continuously flush both eyes with isotonic sodium chloride solution during the process of transport to seek medical attention;
• (3) ingestion do not use emetic, first rinse the oral cavity, if it can be swallowed and accompanied by vomiting reflex but not drooling, ingest about 200mL of water for dilution and promptly send to the doctor.

Therefore, during the experiment, the operator should pay attention to wear appropriate protective clothing, gloves and use protective glasses or face shield.