Pyridine, an organic compound with the chemical formula C5H5N, is a six-membered heterocyclic compound containing a nitrogen heteroatom. It can be regarded as a compound in which one (CH) in the benzene molecule is substituted by N, so it is also called nitrobenzene. It is a colorless or slightly yellow liquid with a stench.
Foreign name: pyridine
Alias: Azabenzene
Chemical formula: C5H5N
Molecular weight: 79.102
CAS login number: 110-86-1
EINECS accession number: 203-809-9
Melting point: -41.6 ℃
Boiling point: 15.3℃
Water soluble: Soluble
Density: 0.983 g/cm³
Exterior: Colorless liquid
Flash point: 20 ℃ (closed)
Application: Used in the manufacture of vitamins, sulfonamides, pesticides and plastics, etc.
Security description: S7; S16; S22; S24/25; S26; S28; S36/37/39; S38; S45; S61
Hazard Symbols: F; Xn
Hazard description: R11; R20/21/22
UN Dangerous Goods Number: 1282
Physical properties:
Melting point: -41.6℃
Boiling point: 115.3℃
Flash point: 20℃
Density: 0.983g/cm3
Ignition temperature: 482℃
Upper explosion limit (V/V): 12.4%
Lower explosion limit (V/V): 1.7%
Critical temperature (℃): 346.85
Critical pressure (MPa): 6.18
Refractive index: 1.509 (20℃)
Appearance: colorless liquid
Solubility: Miscible with water, alcohol, ether, petroleum ether, benzene, oil and other solvents
Chemical properties:
Pyridine and its derivatives are more stable than benzene, and their reactivity is similar to that of nitrobenzene. Typical aromatic electrophilic substitution reactions occur at the 3 and 5 positions, but the reactivity is lower than that of benzene, and nitration, halogenation, sulfonation and other reactions are generally not easy to occur. Pyridine is a weak tertiary amine that can form water-insoluble salts with various acids (picric acid or perchloric acid, etc.) in ethanol solution. The pyridine used in industry contains about 1% of 2-methylpyridine, so it can be separated from its homologues by taking advantage of the difference in salt-forming properties. Pyridine can also form crystalline complexes with various metal ions. Pyridine is easier to reduce than benzene, such as reducing to hexahydropyridine (or piperidine) under the action of metal sodium and ethanol. Pyridine reacts with hydrogen peroxide and is easily oxidized to N-pyridine oxide.
Application
It is used in the manufacture of vitamins, sulfonamides, pesticides and plastics; it can also be used as an alkaline solvent, and it is also an excellent solvent for deacidification and acylation reactions; it can also be used as a carbonyl group for polymerization, oxidation, and acrylonitrile. It can also be used as a catalyst for chemical reactions, etc.; it can also be used as a silicone rubber stabilizer, a raw material for anion exchange membranes, etc.
3-Bromopyridine,4-Methoxypyridine,Intermediates 2-Chloro-3-formyl-6-picoline,5-Bromo-2-methyl-3-nitropyridine Fuxin Custchem Fine Chemical Co., Ltd. , https://www.custchemvip.com
It is still a long way for new energy vehicles to enter the homes of ordinary people. In addition to the government’s “pushing awayâ€, it has to drive through the market to “open and go†to achieve a leap from official vehicles to civilian markets.
Recently, five ministries and commissions such as the Ministry of Finance jointly announced the Implementation Plan for the Purchase of New Energy Vehicles by Government Agencies and Public Institutions (hereinafter referred to as the “Implementation Planâ€), and defined the timetable and roadmap for “new energy†for official vehicles. It was pointed out that from 2014 to 2016, the proportion of new energy vehicles purchased by relevant government agencies and public institutions in total amount of equipment renewal for the year was not less than 30%, and will increase year after year.
Under the background of energy crisis and environmental protection, the promotion of new energy vehicles has become China's national strategy. In fact, before the five ministries and commissions jointly issued a document, this year there has been a round of policies and measures for the promotion of new energy vehicles. In February of this year, the Ministry of Finance and other four ministries issued relevant circulars to clarify the subsidy standards for new energy vehicles in the current two years. Subsequently, pilot cities such as Beijing and Shanghai broke the ice of local protection and opened up local subsidies. In July, the executive meeting of the State Council decided that from September 1, 2014 to the end of 2017, three types of new energy vehicles will be exempted from vehicle purchase tax... a number of policies are intensively introduced, reflecting the determination to promote new energy vehicles. In addition, the “Implementation Plan†also stipulates that the purchase of new energy vehicles is linked to environmental protection, and the proportion of new energy for buses is set for each year, and the entire process of quantitative assessment and feedback supervision is stipulated. The policy guidance is determined, planned, and supervised, and the new energy efficiency of official vehicles can be expected.
Promoting new energy vehicles allows the official vehicles to “run†first. On the one hand, implementation of resistance is even smaller. On the other hand, it also reflects the goal of public funds serving the public interest. However, the official car market is still large. To judge the success or failure of the new energy vehicle strategy, it is still necessary to go back to the market to test it. From the LED industry to photovoltaic power generation, all show that only from the government's main push to market-driven, can these new technologies dock to the market's strong driving force to achieve self-blood. In the area of ​​new energy vehicles, there are long-standing facts about "thermal policies and cold markets." As of June 2013, sales of new energy vehicles in China were less than 20,000, which accounted for less than 0.2% of national vehicle sales, far behind the United States, Japan and other countries. It is still a long way for new energy vehicles to enter the homes of ordinary people. In addition to the government's “pushing awayâ€, it has to “drive and go†through the market to achieve a leap from official vehicles to civilian markets.
First of all, current preferential policies such as subsidies and tax reductions are mainly concentrated in the purchase of cars. To achieve the healthy development of the new energy auto industry, the R&D sector also needs government support. Due to the high cost, even if all kinds of preferential policies are counted, new energy vehicles are still more expensive than traditional energy vehicles. There are also certain gaps between the indicators of cruising range, maximum speed and safety performance and foreign products. In addition, many cities have only two or three models of new energy vehicle catalogs available year after year, and fewer models also constrain the enthusiasm of citizens for “new energy vehiclesâ€. Fundamentally speaking, only by strengthening scientific and technological R&D can it be possible to completely solve these problems; only if it is not inferior to conventional cars in terms of endurance and price, consumers will vote with their feet to realize the new energy of civilian vehicles.
Second, apart from focusing on scientific and technological research and development, how to make full use of the shortcomings in the use of new energy vehicles under the existing conditions is crucial. As we all know, "buying a car with easy charging" is a big problem in the marketization of new energy vehicles. This "Implementation Plan" clearly states that it must be equipped with a charging interface in accordance with the 1:1 configuration of new energy vehicles. To achieve this goal is not easy. Without a charging pile, the car cannot be sold; there are not enough vehicles and charging piles are not profitable. To solve this problem, it may be inevitable that the government will “pave money with money†in the short term, but in the long run, it must be designed. With a reasonable cost sharing and benefit-sharing mechanism, auto manufacturers, power supply companies, and government agencies all need to find mutual benefit conventions.
Third, the government can flexibly use its own policy resources to further increase the "privileges" enjoyed by new energy vehicles. At present, in some motor vehicle restricted cities, new energy vehicles are given priority, and Jiangxi and other places have also reduced the cost of new energy vehicles. While exploring whether these measures can be widely promoted, it is also necessary to explore the possibility of further increasing the "privileges" of new energy vehicles, such as restrictions on single and double numbers in limited cities, free licenses, annual ticket discounts, etc. The attraction of energy vehicles is also helpful.