1,5-Dibromopentane

1,5-Dibromo norbornane, its main use in the "Tiangong Kaiwu" scope, in the classical Chinese form described as follows: This 1,5-dibromo norbornane, in many things has its own function. It can be the base material for synthesizing wonderful medicines in the way of craftsmanship. Physicians and pharmaceuticals often rely on its unique properties to become a good prescription for treating diseases and diseases. Because of its unique structure, the cover can be cleverly combined with various medicinal materials, modulating medicinal properties, and making the medicinal effect more obvious. In the field of utensils manufacturing, it also has extraordinary uses. It can be an additive to color and quality of paints. On the lacquer ware, applying a substance containing this 1,5-dibromo norbornane can make the paint surface more firm, and the color is more radiant, lasting for a long time, making the utensils both beautiful and durable, and can be handed down as a good product. Furthermore, it is related to the art of fire attack. It can help the control of fire a little, or in the ignition of things, use it in moderation, and can adjust the intensity of fire. In wartime, fire attack is an important strategy, and this 1,5-dibromo norbornane can be used in the medicinal induction of fire attack, the production of fire utensils, etc., or it can play a small role to help the benefits of war. Although it is not the key main material of the fire attack, it can also increase the effect of the fire attack if it is properly allocated in the details.

1,5-Dibromoanthraquinone is an organic compound with the following physical properties: In terms of color state, it is often in the state of yellow to orange crystalline powder. This color state characteristic can be regarded as the basis for preliminary identification in many organic synthesis and dye preparation scenarios. Looking at its appearance, it can be preliminarily speculated about its species. The melting point is quite high, about 268-272 ° C. The higher melting point is due to the existence of strong forces between molecules, such as van der Waals force, hydrogen bonding, etc. Such a high melting point makes 1,5-dibromoanthraquinone a stable solid state at general ambient temperature, and it is not easy to melt easily due to temperature fluctuations. This does not require excessive concern about its physical state changes during storage and transportation. In terms of solubility, it is insoluble in water. Water molecules form hydrogen bonds and have a tight structure, while 1,5-dibromoanthraquinone molecules have weak polarity and cannot form effective interactions with water, so it is difficult to dissolve in water. However, it is soluble in some organic solvents, such as hot toluene, xylene, etc. This solubility characteristic is extremely critical in organic synthesis operations, providing ideas for selecting suitable reaction solvents and subsequent product separation and purification. For example, after synthesizing related products, their solubility in specific organic solvents can be used to separate from other impurities by means of extraction. In terms of sublimation, it can be sublimated under certain conditions. The property of sublimation indicates that 1,5-dibromoanthraquinone can directly transform from solid state to gaseous state under specific temperature and pressure conditions. This property may be applied in the field of material purification. By controlling temperature and pressure, 1,5-dibromoanthraquinone is sublimated, and then separated from unsublimated impurities to achieve the purpose of purification.

1% 2C5-dibromo-p-xylene has unique chemical properties. Although this substance is not detailed in Tiangong Kaiwu, it can be deduced according to its chemical general principles and similar characteristics. In this substance, bromine atoms are active. Bromine has strong electronegativity, which makes the carbon-bromine bond electron cloud biased towards bromine, causing the carbon to be partially positively charged and vulnerable to attack by nucleophiles. In case of hydroxyl negative ions, nucleophilic substitution can occur, and bromine is replaced by hydroxyl groups to form corresponding alcohols. When exposed to light or heating, the carbon-bromine bond can homogenize and produce free radicals. If there are olefins in the system, it can initiate free radical addition. Bromine free radicals are added to the double bond of olefins to generate new free radicals, and then interact with dibromo-p-xylene to lengthen the carbon chain and expand the molecular structure. Because of the electron absorption of bromine atoms, the electron cloud density of the benzene ring decreases, resulting in the reduction of the electrophilic substitution activity of the benzene ring. Compared with the reaction of bromine and benzene catalyzed by iron bromide, the bromide of dibromo-p-xylene is more difficult to bromide, and the new substituent has multiple mesopositions. Because of the electron absorption of bromine, the density of the electron cloud of the ortho and para-position decreases even more. < When exposed to fire, heated bromine atoms can form bromine radicals, capture key radicals in the chain reaction during combustion, prevent combustion from spreading, and can be added to materials as flame retardants. This dibromo-p-xylene, due to the existence of bromine atoms, has the characteristics of nucleophilic substitution, free radical reaction, etc., benzene ring electrophilic substitution activity changes, and has flame retardant ability, which is important in the field of organic synthesis and materials.

1,5-Dihydroxylnaphthalene is often used as a test reagent in synthesis as follows: 1,5-Dihydroxylnaphthalene is a key reagent in organic synthesis. In many chemical synthesis reactions, it is often used as a color reagent. For example, in the field of detection and analysis of carbohydrates, 1,5-Dihydroxylnaphthalene can react with carbohydrates under specific conditions to generate products with specific colors, thereby enabling qualitative or quantitative analysis of carbohydrates. This is due to the structure and properties of carbohydrates, which can be combined with 1,5-dihydroxylnaphthalene under suitable pH, temperature and other conditions through a specific chemical reaction mechanism to produce substances with color changes, so that the presence or absence of carbohydrates and their content can be judged according to the depth of color or the presence or absence of color changes. Furthermore, in some organic synthesis routes, 1,5-dihydroxylnaphthalene, due to its unique molecular structure, contains two hydroxyl functional groups, which have certain reactivity and selectivity. It is often used as a key intermediate to participate in the construction of complex organic compounds. It can be connected or transformed with other organic compounds through esterification, etherification, oxidation and other reactions of hydroxyl groups, and gradually build up the molecular framework of the target product, which has important applications in many fields such as drug synthesis and material chemistry. For example, when synthesizing some polymer materials with special properties, 1,5-dihydroxynaphthalene can be used as a monomer or modifier to introduce into the polymer chain, giving the material unique optical, electrical or mechanical properties.

1% 2C5-dibromo norbornene is a key raw material in organic synthesis. The preparation method is as follows: First, the addition reaction is carried out with norbornadiene and bromine as the starting material. Norborndiene has a special double-ring structure and can react with bromine according to the electrophilic addition mechanism. At low temperature and in the presence of a suitable solvent (such as dichloromethane), bromine is slowly added dropwise to the solution containing norborndiene. Bromine positive ions in bromine attack the double bond of norborndiene first to form a brominium ion intermediate, and then bromine negative ions attack the intermediate from the opposite side to form 1% 2C5-dibromo norbornene. This reaction condition is relatively mild, but it is necessary to strictly control the amount of bromine and the drip speed to prevent excessive bromination. Second, norbornene derivatives are used as raw materials. First, functional groups are introduced at specific positions of norbornene through a specific reaction to construct suitable intermediates, and then bromide atoms are precisely introduced into the target position through a bromination reaction to prepare 1% 2C5-dibromo norbornene. This path step may be more complicated, but the selectivity of the reaction check point is better, which is conducive to improving the purity and yield of the product. For example, first let norbornene react with a nucleophilic reagent, introduce an activable double-bond group at the double-bond ortho-position, and then brominate, and bromine atoms are preferentially added to the target double bond. Third, the synthesis is catalyzed by transition metals. Appropriate transition metal catalysts (such as palladium, copper and other complexes) are selected to catalyze the reaction of brominated reagents with norbornene derivatives in the presence of specific ligands and bases. Transition metal catalysts can activate substrates, change reaction paths and activities, and promote the selective formation of 1% 2C5-dibromo norbornene. This method has the advantages of high atomic economy and mild reaction conditions, but catalyst cost and recycling may be issues to be considered.