7758-02-3 Usage
Chemical Description
Potassium bromide is a white crystalline powder used as a spectroscopic standard.
Description
Potassium bromide is a white salt that crystallizes in the cubic rock salt structure, similar to sodium chloride. It is hygroscopic, deliquescent, highly soluble in water, and soluble in some polar organic solvents like glycerol, ethylene glycol, liquid ammonia, and hot ethanol, but insoluble in acetone. Aqueous solutions of potassium bromide are neutral (pH about 7). When dissolved, KBr dissociates completely into its ions, making it a useful source of bromine ions in double displacement reactions or salt metathesis reactions.
Uses
Used in Photographic Industry:
Potassium bromide was used as a secondary halide in combination with an iodide in the paper negative processes, the albumen on glass process, and the wet collodion processes. When silver bromide gelatin emulsion was invented, potassium bromide became the primary halide. It was also used in combination with either bichloride of mercury, copper sulfate, or potassium ferricyanide in photographic bleaches and as a restrainer in alkaline developers used for gelatin plates and developing-out papers.
Used in Infrared Spectroscopy:
Because of its range of transparency to infrared radiation, KBr is used both as a matrix for solid samples and as a prism material in infrared spectroscopy. Potassium bromide is widely used in optics due to its low refractive index and wide spectral range into the infrared with nearly no absorption. As a result, KBr is widely used as infrared optical windows, as infrared beamsplitters, and as substrates for interferometers. Commonly, KBr is used in transmission infrared spectroscopy as a media for powder samples.
Used in Synthesis:
Potassium bromide has been used in synthesis, commonly as a source of bromide ions. For example, double displacement of KBr and bismuth nitrate yielded nanosheets of bismuth oxybromide. Solutions of KBr have also been found to be useful shape-control agents or crystal-habit modifiers in the formation of metal nanocrystals, including palladium nanorods and bimetallic platinum-palladium nanocrystals. KBr is a common source of bromide ions used as nucleophiles in organic chemistry.
Used as a Sedative:
Potassium bromide is also used as a sedative due to its calming effects.
Preparation
Potassium bromide was produced by the action of bromine on hot potassium hydroxide solution or Reacting elemental bromine with potassium hydroxide or potassium iodide will produce the potassium bromide salt:KOH + Br2 → KBr + HOBrKI + Br2 → KBr + I2The reaction of bromine with potassium carbonate and urea is the basis of the process. The first step of the process involves the addition of K2SO4 to the potassium carbonate solution, followed by heating to 80 °C. After the lead-containing precipitate is removed by filtration, the bromine and urea are added, and the temperature and pH are adjusted to 30 °C and 6.0-6.5, respectively. Potassium bromide is recovered by recrystallization after reduction of volume of the reacting solution by evaporation. The sulfate can be removed from the solution by addition of BaBr2.
Reactivity Profile
Potassium bromide is not in generally strongly reactive. A weak reducing agent, incompatible with oxidizing agents. Also incompatible with salts of mercury and silver. Violent reactions occur with bromine trifluoride. May react with nitrous ether spirit, many alkaloidal salts and starch. May also react with acids . Reacts with concentrated sulfuric acid to generate fumes of hydrogen bromide.
Hazard
Toxic by ingestion and inhalation
Fire Hazard
Flash point data for Potassium bromide are not available; however, Potassium bromide is probably nonflammable.
Flammability and Explosibility
Nonflammable
Biochem/physiol Actions
Potassium bromide (KBr) is used as an anticonvulsant and sedative. KBr is used for optical windows and prisms. KBr is transparent in the wide wavelength range from near ultraviolet to long wave infrared. It is employed in the sample preparation for infrared transmission spectra.
Safety Profile
Moderately toxic by
ingestion and intraperitoneal routes. Large
doses can cause central nervous system
depression. Prolonged inhalation may cause skin eruptions. Mutation data reported.
Violent reaction with BrF3. When heated to
decomposition it emits toxic fumes of K2O
and Br-. See also BROMIDES.
Veterinary Drugs and Treatments
Bromides are used both as primary therapy and as adjunctive therapy
to control seizures in dogs that are not adequately controlled by
phenobarbital (or primidone) alone (when steady state trough phenobarbital
levels are >30 mcg/mL for at least one month). While
historically bromides were only recommended for use alone in patients
suffering from phenobarbital (or primidone) hepatotoxicity,
they are more frequently used as a drug of first choice.
Although not frequently used, bromides are also considered
suitable by some for use in cats with chronic seizure disorders, but
cats may be more susceptible to the drug’s adverse effects.
Purification Methods
Crystallise the bromide from distilled water (1mL/g) between 100o and 0o. Wash it with 95% EtOH, followed by Et2O. Dry it in air, then heat it at 115o for 1hour, pulverize it, then heat it in a vacuum oven at 130o for 4hours. It has also been crystallised from aqueous30% EtOH, or EtOH, and dried over P2O5 under vacuum before heating in an oven.
Check Digit Verification of cas no
The CAS Registry Mumber 7758-02-3 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,7,5 and 8 respectively; the second part has 2 digits, 0 and 2 respectively.
Calculate Digit Verification of CAS Registry Number 7758-02:
(6*7)+(5*7)+(4*5)+(3*8)+(2*0)+(1*2)=123
123 % 10 = 3
So 7758-02-3 is a valid CAS Registry Number.
InChI:InChI=1/BrH.K/h1H;/q;+1/p-1
7758-02-3Relevant articles and documents
Ion Exchange of Layered Alkali Titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with Alkali Halides by the Solid-State Reactions at Room Temperature
Ogawa, Makoto,Saothayanun, Taya Ko,Sirinakorn, Thipwipa Tip
, p. 4024 - 4029 (2020/04/08)
Ion exchange of layered alkali titanates (Na2Ti3O7, K2Ti4O9, and Cs2Ti5O11) with several alkali metal halides surprisingly proceeded in the solid-state at room temperature. The reaction was governed by thermodynamic parameters and was completed within a shorter time when the titanates with a smaller particle size were employed. On the other hand, the required time for the ion exchange was shorter in the cases of Cs2Ti5O11 than those of K2Ti4O9 irrespective of the particle size of the titanates, suggesting faster diffusion of the interlayer cation in the titanate with lower layer charge density.
A novel zero valent metal bismuth for bromate removal: Direct and ultraviolet enhanced reduction
Huang, Hong,Liu, Guoshuai,Wang, Xiuheng
, p. 4148 - 4155 (2020/02/04)
Bromate (BrO3-) is a carcinogenic and genotoxic by-product of the ozone disinfection process. In this study, a new zero-valent metal, bismuth, was used to reduce bromate. Bismuth samples were prepared by a solvothermal method and characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The morphology of the bismuth powder was microspheres assembled with dense nanosheets. The kinetics of the direct bromate reduction by bismuth accorded with the pseudo-first-order kinetics model. The rate coefficients of the initial bromate concentration of 1.00 mg L-1, 2.50 mg L-1, 5.00 mg L-1 were identically close to 0.08 min-1. For 0.20 mg L-1, a reaction rate coefficient near 0.10 min-1 was obtained. The reducing products of bromate included bromide ions (Br-) and bismuth oxybromides. The bromate removal efficiency was enhanced remarkably in the presence of ultraviolet (UV) light, and the corresponding kinetic coefficient was 4 times higher than that of direct reduction. The mechanism of ultraviolet enhancement was analyzed by diffuse reflectance spectroscopy (DRS), the density functional theory (DFT) calculation, open circuit potential (OCP) analysis, photocurrent measurement and linear sweep voltammetry (LSV). Besides, the influence of dissolved oxygen (DO) on bromate reduction efficiency and the sustainability of the as-prepared sample were investigated. DO inhibited the reduction rate obviously, but showed a slight effect on the formation of bromide ions. In the long-term periodic experiments, the kinetic coefficient decay occurred in both direct (without UV irradiation) and ultraviolet assisted bromate reduction. However, the kinetic coefficient of UV-assisted reduction (0.115 min-1) was about 2 times higher than that of the direct reduction in the last cycle of periodic experiments. In conclusion, the novel bromate reduction strategy based on the zero-valent bismuth metal material has been proved efficient and sustainable, which contributes to the development of drinking water treatment technologies.
Synthesis, characterization, and catalytic behavior of methoxy- and dimethoxy-substituted pyridinium-type ionic liquids
Manikandan, Chitrarasu,Ganesan, Kilivelu
, p. 3362 - 3367 (2014/12/11)
Synthesis of methoxy-substituted pyridinium-type ionic liquids from a nontoxic and easy method is described. Catalytic behaviors of synthesized ionic liquids were investigated with various concentrations for the Mannich reaction. We have observed that methoxy- and dimethoxy-substituted pyridinium bromides showed better catalytic behavior than other ionic liquids.
Xi:Irritant;
