How do you make benzocaine from p-aminobenzoic acid?
Benzocaine is the derivative of p-aminobenzoic acid and can be synthesized via the Fischer esterification reaction. It can be prepared from p -toluidine by a four-step synthesis. The problem of a synthesis of this type is that the overall yield of the final product is usually quite low.
What is benzocaine made from?
Benzocaine is the ethyl ester of p -aminobenzoic acid (PABA). It can be prepared from PABA and ethanol by Fischer esterification or via the reduction of ethyl p -nitrobenzoate.
How do you make benzocaine from ethyl ester?
Benzocaine is the ethyl ester of 4-aminobenzoic acid (2.3.1). The classic, optimal way of benzocaine synthesis is the reduction of the nitro group of the ethyl ester of 4-nitrobenzoic acid to benzocaine by hydrogen, which generates directly in the reaction medium by the reaction of iron filings with dilute acids [24–26 ].
What is the mechanism of action of benzocaine?
Benzocaine is an ester of paraaminobenzoic acid, lacking the terminal diethylamino group of procaine, with anesthetic activity. Benzocaine binds to the sodium channel and reversibly stabilizes the neuronal membrane which decreases its permeability to sodium ions. Depolarization of the neuronal membrane is inhibited,...
What is benzocaine made from?
Benzocaine is a chemical compound derived from para-aminobenzoic acid and ethanol. It is a white, odorless, crystalline powder. It acts on neuronal membranes and blocks nerve signals in the body. Its numbing effects are temporary.
Why is absolute ethanol used in the synthesis of benzocaine?
Explanation: Benzocaine is soluble in Ethanol, Methanol and Diethyl Ether. But it is not very soluble in water. Having water in the solution would decrease the solubility and would create a lot of hassle later.
How is Novocaine synthesized?
Procaine, the 2-diethylaminoethyl ester of 4-aminobenzoic acid (2.1. 1), better known as novocaine, is synthesized in two ways. The first way consists of the direct reaction of the 4-aminobenzoic acid ethyl ester with 2-diethylaminoethanol in the presence of sodium ethoxide.
Whats stronger benzocaine or lidocaine?
Results showed that lidocaine and benzocaine were equally effective, and both were better than placebo in reducing the pain of needle insertion.
What is the limiting reagent in benzocaine synthesis?
As the 4-aminobenzoic acid is the limiting amount, it is this quantity that we should use in our yield calculation.
What is the difference between absolute ethanol and 95% ethanol?
The ethanol-based products commonly used in laboratories are 95% pure. In this environment, ethanol is typically used to fuel alcohol lamps, preserve biological specimens, disinfect laboratory equipment, and dissolve organic compounds. Absolute ethanol, on the other hand, has a purity level of between 99% and 100%.
Why is Novocaine no longer used?
Novocain (or its non-trade name, Procain) was discontinued in dentistry because it can cause an allergic reaction in some patients. It was replaced in 1948 by Lidocaine, which is less allergenic, faster-acting, and longer-lasting.
What plant does Novocaine come from?
erythroxylum cocaThe Indian Dental Association mention that Lidocaine and novocaine are cocoa plant (erythroxylum coca) derivative and therefore safe. It often works very quickly and its effects do not usually last long.
How is lidocaine synthesized?
Lidocaine, 2-(diethylamino)-N-(2,6-dimethylphenyl)acetamide (2.2. 2), is synthesized from 2,6-dimethylaniline upon reaction with chloroacetic acid chloride, which gives α-chloro-2,6-dimethylacetanilide (2.1. 1), and its subsequent reaction with diethylamine [11]. Lidocaine is the most widely used local anesthetic.
What happens if you use too much benzocaine?
Benzocaine and other local anesthetics can cause methemoglobinemia, a serious condition in which the amount of oxygen carried through the blood is greatly reduced. This condition is life-threatening and can result in death.
How much benzocaine does it take to overdose?
Poisindex® states that the threshold toxic dose for benzocaine is 22-40 mg/kg.
What is the most powerful topical anesthetic?
The strongest numbing cream that is used by dermatologists is a triple anesthetic cream. The most common formulation is a combination of benzocaine 20%, lidocaine 6%, and tetracaine 4%, which is also called BLT cream.
Why is it necessary to use absolute ethanol if you were preparing an ester using ethanol?
By using absolute ethanol, ester becomes acid due to the hydrogen from water. Therefore, absolute ethanol is chosen for this reaction which will lead the reaction to right (Forward reaction), rather than using any forms of diluted ethanol that could only negatively influence reaction for ester formation.
Why do we use absolute ethanol in this reaction instead of the more common 95% ethanol?
The most important reason for using absolute ethanol is that the Fischer esterification is an equilibrium reaction with a Keq≈4 . If you use ordinary 95 % ethanol as a reactant, the 5 % water will push the position of equilibrium somewhat to the left and decrease your yield.
What is the purpose of Fischer esterification?
Fischer Esterification is an organic reaction which is employed to convert carboxylic acids in the presence of excess alcohol and a strong acid catalyst to give an ester as the final product.
Why is it important to neutralize the reaction mixture with nahco3 during the work up?
Why is it important to neutralize the reaction mixture during the workup? 1. Neutralization prevents the ester from undergoing the reverse reaction to regenerate the carboxylic acid starting material.
What is the best topical anesthesia for superficial pain?
Local anesthetics, particularly benzocaine and lidocaine, are found in a number of topical mixtures for treatment of minor superficial pain. These may be found in both prescription and over-the-counter formulations. An adhesive patch that contains 5% lidocaine is available by prescription. This has been successfully used for treatment of focal tactile hyperalgesia, such as that seen in post-herpetic neuralgia. A eutectic mixture of 2.5% lidocaine and 2.5% prilocaine (EMLA) provides anesthesia for superficial procedures including venipuncture and some skin graft harvesting, but requires placement of an occlusive dressing and ∼60 min to reach full efficacy. Local anesthetics are commonly administered by focal infiltration to provide temporary loss of sensation for minor invasive procedures such as closure of a laceration with sutures. Mepivacaine is not effective for topical or infiltration anesthesia. If anesthesia is desired in a larger region, local anesthetics can be injected directly adjacent to major nerves or nerve roots such as is often performed for dental procedures and minor surgical procedures, especially on extremities, producing a nerve block. In addition, regional anesthesia in the lower leg and foot or lower arm and hand can be performed by administering intravenous lidocaine or prilocaine in a region that has been isolated from the general circulation by compressive exsanguination and application of a tourniquet. This is commonly known as a Bier's block. Injections into the spinal space, either epidurally or intrathecally are often used for peri- and post-operative pain, in addition to neuropathic pain states. With chronic pain states, delivery of local anesthetics with or without the addition of opiates via an implanted permanent intrathecal catheter and subcutaneous pump can provide a high degree of pain relief in selected patients. Low dose, intravenous lidocaine infusions have also been effective in treating some neuropathic pain states. Lidocaine can be used in the treatment of ventricular tachycardia or fibrillation. As will be discussed below, cardiovascular effects are an important toxicological consideration of lidocaine.
How to dissolve procainamide hydrochloride?
Dissolve the Procainamide hydrochloride by placing the flask in an ultrasonic bath at 20-25°C for 2-3 minutes.
How to titrate benzocaine?
Weigh approximately 150-170 mg of benzocaine into a 250 mL conical flask. Transfer 100 mL of acetic acid into the flask, and dissolve the benzocaine in the acid by placing the container in an ultrasonic bath at 20-25°C for 2-3 minutes. Add 10 mL of a mercuric acetate solution, and let the flask stand for 45 minutes. Add 2 drops of the crystal violet indicator, and titrate with 0.1N perchloric acid to a green end point with absence of blue shades. Accurately weigh about 135 mg of the Procainamide hydrochloride sample into the flask containing the neutralized benzocaine solution. Dissolve the Procainamide hydrochloride by placing the flask in an ultrasonic bath at 20-25°C for 2-3 minutes. Titrate with the standardized perchloric acid to a green end point with the absence of blue shades. The percent of Procainamide is calculated using:
How long does benzocaine last?
It begins to work 15–30 sec after application and lasts 12–15 min. It is also used under the names anestezin, dermoplast, and others.
What is the ethyl ester of 4-aminobenzoic acid?
Benzocaine is the ethyl ester of 4-aminobenzoic acid (2.3.1). The classic, optimal way of benzocaine synthesis is the reduction of the nitro group of the ethyl ester of 4-nitrobenzoic acid to benzocaine by hydrogen, which generates directly in the reaction medium by the reaction of iron filings with dilute acids [24–26 ].
How long does hemolysis last?
The normal life span of a circulating erythrocyte is approximately 120 days. Any degree of reduction in this life span represents hemolysis. If hemolysis exceeds the regeneration of new erythrocytes, it results in anemia. Several chemicals or their reactive metabolites can cause hemolysis via oxidative injury (e.g., chlorates, benzocaine, methylene blue, nitrites, phenol, sulfonamides). Other chemicals can cause hemolysis in the absence of oxidant injury, for example, lead and arsine. Lead causes anemia by a combination of mechanisms, including the inhibition of several enzymes involved in heme synthesis. Toxic levels of lead above 25 μg dl−1 can be treated with chelation therapy. The mechanism of hemolysis behind arsine toxicity involves the fixation of arsine by sulfhydryl groups of hemoglobin and impairment of membrane proteins, including Na+ –K +–ATPase. Supportive care and cessation of exposure are the treatments of choice in most cases. In severe cases, exchange transfusion can be used.
What is Bier's block?
In addition, regional anesthesia in the lower leg and foot or lower arm and hand can be performed by administering intravenous lidocaine or prilocaine in a region that has been isolated from the general circulation by compressive exsanguination and application of a tourniquet. This is commonly known as a Bier's block.
How does Sensuino work?from bath.ac.uk
The Sensuino prototype is built using an Arduino, a microcomputer that is commonly used in embedded systems, as its foundation and allows us through the use of programming to interact directly with hardware such as LEDs, LCDs, motors and sensors. Our current prototype utilises a thermistor to measure temperature, a photoresistor to measure the intensity of light and a LCD to output the data and allow the user to change the settings such as the intensity of light at which the user wants the lights to turn on and also the speed of the fan. The thermistor is a sensor used to measure the temperature and it works by resisting the current based on the temperature of the environment, the higher the temperature, the greater the resistance. Our software that is uploaded on the Arduino will measure the current and then convert this through the use of a formula to degrees Celsius. Depending on this temperature the motor, controlling the fan, spins faster or slower to lower the temperature. The photoresistor is used to measure the intensity of light and will also like the thermistor resist the current based on the light intensity, the darker it is the lower the resistance. The software in this case based on the custom threshold set by the user will turn on the LEDs based on the intensity of light. The current version of the prototype currently uses a motor as the fan, the speed of the motor is dependent on the flow of the current and we can adjust this through the use of our software which increases the current if the temperature is higher which in turns spins the motor faster. A light-emitting diode is a two-lead semiconductor light source, that emits light when current is supplied. Our prototype uses four LEDs, which turns on based on the threshold value of the intensity of light set by the user and measured by the photoresistor. Home automation is the future and the industry is rapidly growing, with IoT (Internet of Things) becoming cheaper and more accessible, the Sensuino is the basis of any home automation system. It automatically adapts based on the environment without any input from the user. It is very easy to think of our prototype in a limited sense, but it can be applied to a variety of situations. For example instead of a motor, the system could be hooked up to an air conditioning unit, in place of the LEDs we can have an expensive chandelier in the lounge.
What is esters used for?from slideshare.net
Esters are used in a wide range of fields, including the medical, cosmetology and fuelsindustry. For instance, biodiesel fuel is an alternative fuel source that is composed mainly ofmonoalkyl esters from vegetable oil or animal fats (1).
What is the purpose of ester in chemistry?from slideshare.net
1. I. Introduction Esters are important compounds in organic chemistry. They are used in numerous types ofsynthetic reactions, to create different products for a vast array of purposes, including medicinaland cosmetic. To produce an ester, one can utilize an esterification reaction. In particular, theFischer Esterification ...
What is the use of esters in perfume?from slideshare.net
Other esters are used for their strongfruity smells in cosmetology for perfumes, while still others are used as flavor additives in foods.Benzocaine is an ester that has been used in the medical industry as a local anasethetic fordecades.
What is Fischer's esterification?from slideshare.net
Conclusion Fischer Esterification was used as a means to synthesize benzocaine, an ester, from p-aminobenzoic acid, a carboxylic acid. This is done by adding excess alcohol, in this case 6. 7. ethanol, and catalytic sulfuric acid. The reaction takes place as a reflux, and yields large, whiteand flaky crystals.
Why are protons not asshifted as the next two peaks?from slideshare.net
These protons are deshielded by the nitrogen atom, but are not asshifted as far as the next two peaks because they are so far from the oxygen atoms of the ester.The next peak, a doublet with a chemical shift of 6.48ppm shows the symmetrical hydrogenatoms on the benzene ring closest to the ester substituent.
What is game theory?from bath.ac.uk
Game theory is a branch of applied maths that allows us to model and analyse zero-sum games between intelligent rational decision makers. Connect 4 is an example of a game that can be modelled and “solved” using game theory.
What is the name of the drug that is used to treat ulcers?
Benzocaine. Benzocaine , sold under the brand name Orajel amongst others, is an ester local anesthetic commonly used as a topical pain reliever or in cough drops. It is the active ingredient in many over-the-counter anesthetic ointments such as products for oral ulcers.
What is the bath solution used for amphibians?
A bath solution of benzocaine has been used to anesthetize amphibians for surgery.
How is benzocaine made?
Synthesis. Benzocaine can be prepared by esterification using 4-aminobenzoic acid and ethanol. It can also be prepared by reduction of ethyl 4-nitrobenzoate to the amine. In industrial practice, the reducing agent is usually iron and water in the presence of a little acid.
What is the benzocaine in Jiffy Toothache Drops?
Jiffy Toothache Drops bottle (7.75% Benzocaine) Benzocaine is used as a key ingredient in numerous pharmaceuticals: Some glycerol-based ear medications for use in removing excess wax as well as relieving ear conditions such as otitis media and swimmers ear. Some previous diet products such as Ayds. Some condoms designed to prevent premature ...
How old do you have to be to take benzocaine?
As a result, the FDA has stated that benzocaine products should not be used in children under two years of age, unless directed by and supervised by a healthcare professional. In European countries, the contraindication applies to children under 12 years of age.
When was benzocaine first synthesized?
History. Benzocaine was first synthesized in 1890 by the German chemist Eduard Ritsert (1859–1946), in the town of Eberbach and introduced to the market in 1902 under the name "Anästhesin".
What is the melting point of benzocaine?
The melting point of benzocaine is 88–90 °C, and the boiling point is about 310 °C. The density of benzocaine is 1.17 g/cm 3 . Benzocaine is commonly found, particularly in Britain, as an additive in street cocaine and also as a bulking agent in "legal highs".
How does Sensuino work?from bath.ac.uk
The Sensuino prototype is built using an Arduino, a microcomputer that is commonly used in embedded systems, as its foundation and allows us through the use of programming to interact directly with hardware such as LEDs, LCDs, motors and sensors. Our current prototype utilises a thermistor to measure temperature, a photoresistor to measure the intensity of light and a LCD to output the data and allow the user to change the settings such as the intensity of light at which the user wants the lights to turn on and also the speed of the fan. The thermistor is a sensor used to measure the temperature and it works by resisting the current based on the temperature of the environment, the higher the temperature, the greater the resistance. Our software that is uploaded on the Arduino will measure the current and then convert this through the use of a formula to degrees Celsius. Depending on this temperature the motor, controlling the fan, spins faster or slower to lower the temperature. The photoresistor is used to measure the intensity of light and will also like the thermistor resist the current based on the light intensity, the darker it is the lower the resistance. The software in this case based on the custom threshold set by the user will turn on the LEDs based on the intensity of light. The current version of the prototype currently uses a motor as the fan, the speed of the motor is dependent on the flow of the current and we can adjust this through the use of our software which increases the current if the temperature is higher which in turns spins the motor faster. A light-emitting diode is a two-lead semiconductor light source, that emits light when current is supplied. Our prototype uses four LEDs, which turns on based on the threshold value of the intensity of light set by the user and measured by the photoresistor. Home automation is the future and the industry is rapidly growing, with IoT (Internet of Things) becoming cheaper and more accessible, the Sensuino is the basis of any home automation system. It automatically adapts based on the environment without any input from the user. It is very easy to think of our prototype in a limited sense, but it can be applied to a variety of situations. For example instead of a motor, the system could be hooked up to an air conditioning unit, in place of the LEDs we can have an expensive chandelier in the lounge.
What is esters used for?from slideshare.net
Esters are used in a wide range of fields, including the medical, cosmetology and fuelsindustry. For instance, biodiesel fuel is an alternative fuel source that is composed mainly ofmonoalkyl esters from vegetable oil or animal fats (1).
What is the purpose of ester in chemistry?from slideshare.net
1. I. Introduction Esters are important compounds in organic chemistry. They are used in numerous types ofsynthetic reactions, to create different products for a vast array of purposes, including medicinaland cosmetic. To produce an ester, one can utilize an esterification reaction. In particular, theFischer Esterification ...
What is the use of esters in perfume?from slideshare.net
Other esters are used for their strongfruity smells in cosmetology for perfumes, while still others are used as flavor additives in foods.Benzocaine is an ester that has been used in the medical industry as a local anasethetic fordecades.
What is Fischer's esterification?from slideshare.net
Conclusion Fischer Esterification was used as a means to synthesize benzocaine, an ester, from p-aminobenzoic acid, a carboxylic acid. This is done by adding excess alcohol, in this case 6. 7. ethanol, and catalytic sulfuric acid. The reaction takes place as a reflux, and yields large, whiteand flaky crystals.
Why are protons not asshifted as the next two peaks?from slideshare.net
These protons are deshielded by the nitrogen atom, but are not asshifted as far as the next two peaks because they are so far from the oxygen atoms of the ester.The next peak, a doublet with a chemical shift of 6.48ppm shows the symmetrical hydrogenatoms on the benzene ring closest to the ester substituent.
What is game theory?from bath.ac.uk
Game theory is a branch of applied maths that allows us to model and analyse zero-sum games between intelligent rational decision makers. Connect 4 is an example of a game that can be modelled and “solved” using game theory.
What is the most favorable course of action for a chemical?
SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.
What is local anesthesia?
Anesthetics, Local. Drugs that block nerve conduction when applied locally to nerve tissue in appropriate concentrations. They act on any part of the nervous system and on every type of nerve fiber. In contact with a nerve trunk, these anesthetics can cause both sensory and motor paralysis in the innervated area.
What is a lubricant used for?
For general use as a lubricant and topical anesthetic on esophagus , larynx, mouth, nasal cavity, rectum, respiratory tract or trachea, urinary tract, vagina. It is also used to suppress gag reflex.
What is surface anaesthetic?
A surface anaesthetic, it is used to suppress the gag reflex, and as a lubricant and topical anaesthetic on the larynx, mouth, nasal cavity , respiratory tract, oesophagus, rectum, urinary tract, and vagina. It has a role as a topical anaesthetic, an antipruritic drug, an allergen and a sensitiser.
What is the Henry's law constant for benzocaine?
The Henry's Law constant for benzocaine is estimated as 1.6X10-8 atm-cu m/mole (SRC) using a fragment constant estimation method (1). This Henry's Law constant indicates that benzocaine is expected to be essentially nonvolatile from water surfaces (2). Benzocaine is not expected to volatilize from dry soil surfaces (SRC) based upon an estimated vapor pressure of 2.6X10-4 mm Hg (SRC), determined from a fragment constant method (3).
What is the KoC of benzocaine?
According to a classification scheme (3), this estimated Koc value suggests that benzocaine is expected to have moderate mobility in soil. However, aromatic amines are expected to bind strongly to humus or organic matter in soils due to the high reactivity of the aromatic amino group (4,5), suggesting that mobility may be much lower in some soils (SRC).
What is the vapor pressure of benzocaine?
If released to air, an estimated vapor pressure of 2.6X10-4 mm Hg at 25 °C indicates benzocaine will exist in both the vapor and particulate phases in the ambient atmosphere.
How does Sensuino work?from bath.ac.uk
The Sensuino prototype is built using an Arduino, a microcomputer that is commonly used in embedded systems, as its foundation and allows us through the use of programming to interact directly with hardware such as LEDs, LCDs, motors and sensors. Our current prototype utilises a thermistor to measure temperature, a photoresistor to measure the intensity of light and a LCD to output the data and allow the user to change the settings such as the intensity of light at which the user wants the lights to turn on and also the speed of the fan. The thermistor is a sensor used to measure the temperature and it works by resisting the current based on the temperature of the environment, the higher the temperature, the greater the resistance. Our software that is uploaded on the Arduino will measure the current and then convert this through the use of a formula to degrees Celsius. Depending on this temperature the motor, controlling the fan, spins faster or slower to lower the temperature. The photoresistor is used to measure the intensity of light and will also like the thermistor resist the current based on the light intensity, the darker it is the lower the resistance. The software in this case based on the custom threshold set by the user will turn on the LEDs based on the intensity of light. The current version of the prototype currently uses a motor as the fan, the speed of the motor is dependent on the flow of the current and we can adjust this through the use of our software which increases the current if the temperature is higher which in turns spins the motor faster. A light-emitting diode is a two-lead semiconductor light source, that emits light when current is supplied. Our prototype uses four LEDs, which turns on based on the threshold value of the intensity of light set by the user and measured by the photoresistor. Home automation is the future and the industry is rapidly growing, with IoT (Internet of Things) becoming cheaper and more accessible, the Sensuino is the basis of any home automation system. It automatically adapts based on the environment without any input from the user. It is very easy to think of our prototype in a limited sense, but it can be applied to a variety of situations. For example instead of a motor, the system could be hooked up to an air conditioning unit, in place of the LEDs we can have an expensive chandelier in the lounge.
What is esters used for?from slideshare.net
Esters are used in a wide range of fields, including the medical, cosmetology and fuelsindustry. For instance, biodiesel fuel is an alternative fuel source that is composed mainly ofmonoalkyl esters from vegetable oil or animal fats (1).
What is the purpose of ester in chemistry?from slideshare.net
1. I. Introduction Esters are important compounds in organic chemistry. They are used in numerous types ofsynthetic reactions, to create different products for a vast array of purposes, including medicinaland cosmetic. To produce an ester, one can utilize an esterification reaction. In particular, theFischer Esterification ...
What is the use of esters in perfume?from slideshare.net
Other esters are used for their strongfruity smells in cosmetology for perfumes, while still others are used as flavor additives in foods.Benzocaine is an ester that has been used in the medical industry as a local anasethetic fordecades.
What is Fischer's esterification?from slideshare.net
Conclusion Fischer Esterification was used as a means to synthesize benzocaine, an ester, from p-aminobenzoic acid, a carboxylic acid. This is done by adding excess alcohol, in this case 6. 7. ethanol, and catalytic sulfuric acid. The reaction takes place as a reflux, and yields large, whiteand flaky crystals.
Why are protons not asshifted as the next two peaks?from slideshare.net
These protons are deshielded by the nitrogen atom, but are not asshifted as far as the next two peaks because they are so far from the oxygen atoms of the ester.The next peak, a doublet with a chemical shift of 6.48ppm shows the symmetrical hydrogenatoms on the benzene ring closest to the ester substituent.
What is game theory?from bath.ac.uk
Game theory is a branch of applied maths that allows us to model and analyse zero-sum games between intelligent rational decision makers. Connect 4 is an example of a game that can be modelled and “solved” using game theory.
What temperature is the esterification step?
The esterification step was screened at different reaction temperatures, but good conversions were observed only above 150 °C, being the best condition a temperature of 180 °C for 3 h. Reduction of nitro group can be performed by different heterogeneous catalysts, we have chosen Pd/C since is a cheap and readily available catalyst which can afford the desired product under mild conditions on moderated reaction time. Both steps are simple and reproducible on gram scale. p -Amino benzoic acid ethyl ester ( 4) can be obtained after recrystallization with 92% of purity.
How to synthesize ethyl ester?
Two different approaches can be used starting from the esterification of p -nitro benzoic acid to its ethyl ester followed by nitro reduction or it could start with nitro re duction leading to p -amino benzoic acid, followed by formation of the related ethyl ester product (Scheme 1) [ 3 ].
What is benzocaine used for?
Benzocaine, an ethyl ester of p -amino benzoic acid ( 1 ), is a local anesthetic generally used as a topic pain reliever, which can also be found in many other anesthetic preparations. It was first synthesized in 1888 by the German chemist/pharmacist Eduard Ritsert. As early as 1888, Ritsert had been working on the production of an antipyretic to replace the toxic and harmless phenacetin when he synthesized p -aminobenzoic acid ethyl ester which did not presented any antipyretic activity, but it did have a local anesthetic effect. Ritsert left the new substance to the Hoechst company, where it was marketed under the name “anesthetic”, which became of outstanding importance in medicine as local anesthetics, with special mention being made of “Novocaine” (diethylaminoethyl p -aminobenzoate) invented by Alfred Einhorn in 1905 (Fig. 1) [ 1, 2 ].
What was Ritsert's first antipyretic?
As early as 1888, Ritsert had been working on the production of an antipyretic to replace the toxic and harmless phenacetin when he synthesized p -aminobenzoic acid ethyl ester which did not presented any antipyretic activity, but it did have a local anesthetic effect.
What are the advantages of continuous flow?
Compared to batch technology, continuous-flow process has several advantages [ 5, 6, 7, 8, 9 ]. The precise control of reaction parameters as temperature, residence time, pressure and stoichiometry are more effective [ 10 ]. This perfect precision increases the selectivity with high reproducibility and allows the scale-up and better reaction yields. Plus, the continuous flow system minimizes the hazard and improves the heat transfer efficiency due to smaller volume of reactor, so that the thermal unstable molecules are prevented to decomposition [ 11, 12, 13, 14 ].
Is benzocaine an anesthetic?
Benzocaine (ethyl p -aminobenzoate), ethyl ester of p -aminobenzoic acid, is an anesthetic acting as a blocker of the nerve impulses and reducing the permeability of neuronal membrane to sodium iodide, it has become widespread in the pharmaceutical industry having applications as an anesthetic prior to exams such as endoscopy or as a “retarding” agent when inserted in condom. Due to the wide insertion in the pharmaceutical market, the methodologies for obtaining this molecule have already been elucidated and published in the literature, however the application of traditional reactions in refined systems, such as continuous flow are a technological bottleneck that allow approaches aimed at the optimization of productivity. Thus, the present work aimed to apply the reduction and esterification of p -nitrobenzoic acid in one step continuous flow systems, optimizing the reaction time and sequences, in order to add relevance and technology to the process as a whole. The model applied in a continuous flow system generated extremely positive values compared to the present literature, which include results with high conversion (> 99%) and selectivity (> 99%), in residence times that reach up to a minimum of 12 s.
Is Fischer's esterification simple?
The esterification reaction is quite simple and any protocol for a Fischer esterification would in the end lead to the formation of the desire d ester with small differences on yields. Aromatic nitro reduction has already been well investigated over literature and many metal catalysts and biocatalysts can be found over literature with different reaction times and conversion profiles. Despite the simplicity of the chemical reactions behind this important molecule, continuous-flow technology has not yet explored its potential in order to deliver a simple and fast methodology to obtain such compound [ 4 ].
How does Sensuino work?from bath.ac.uk
The Sensuino prototype is built using an Arduino, a microcomputer that is commonly used in embedded systems, as its foundation and allows us through the use of programming to interact directly with hardware such as LEDs, LCDs, motors and sensors. Our current prototype utilises a thermistor to measure temperature, a photoresistor to measure the intensity of light and a LCD to output the data and allow the user to change the settings such as the intensity of light at which the user wants the lights to turn on and also the speed of the fan. The thermistor is a sensor used to measure the temperature and it works by resisting the current based on the temperature of the environment, the higher the temperature, the greater the resistance. Our software that is uploaded on the Arduino will measure the current and then convert this through the use of a formula to degrees Celsius. Depending on this temperature the motor, controlling the fan, spins faster or slower to lower the temperature. The photoresistor is used to measure the intensity of light and will also like the thermistor resist the current based on the light intensity, the darker it is the lower the resistance. The software in this case based on the custom threshold set by the user will turn on the LEDs based on the intensity of light. The current version of the prototype currently uses a motor as the fan, the speed of the motor is dependent on the flow of the current and we can adjust this through the use of our software which increases the current if the temperature is higher which in turns spins the motor faster. A light-emitting diode is a two-lead semiconductor light source, that emits light when current is supplied. Our prototype uses four LEDs, which turns on based on the threshold value of the intensity of light set by the user and measured by the photoresistor. Home automation is the future and the industry is rapidly growing, with IoT (Internet of Things) becoming cheaper and more accessible, the Sensuino is the basis of any home automation system. It automatically adapts based on the environment without any input from the user. It is very easy to think of our prototype in a limited sense, but it can be applied to a variety of situations. For example instead of a motor, the system could be hooked up to an air conditioning unit, in place of the LEDs we can have an expensive chandelier in the lounge.
What is esters used for?from slideshare.net
Esters are used in a wide range of fields, including the medical, cosmetology and fuelsindustry. For instance, biodiesel fuel is an alternative fuel source that is composed mainly ofmonoalkyl esters from vegetable oil or animal fats (1).
What is the purpose of ester in chemistry?from slideshare.net
1. I. Introduction Esters are important compounds in organic chemistry. They are used in numerous types ofsynthetic reactions, to create different products for a vast array of purposes, including medicinaland cosmetic. To produce an ester, one can utilize an esterification reaction. In particular, theFischer Esterification ...
What is the use of esters in perfume?from slideshare.net
Other esters are used for their strongfruity smells in cosmetology for perfumes, while still others are used as flavor additives in foods.Benzocaine is an ester that has been used in the medical industry as a local anasethetic fordecades.
What is Fischer's esterification?from slideshare.net
Conclusion Fischer Esterification was used as a means to synthesize benzocaine, an ester, from p-aminobenzoic acid, a carboxylic acid. This is done by adding excess alcohol, in this case 6. 7. ethanol, and catalytic sulfuric acid. The reaction takes place as a reflux, and yields large, whiteand flaky crystals.
Why are protons not asshifted as the next two peaks?from slideshare.net
These protons are deshielded by the nitrogen atom, but are not asshifted as far as the next two peaks because they are so far from the oxygen atoms of the ester.The next peak, a doublet with a chemical shift of 6.48ppm shows the symmetrical hydrogenatoms on the benzene ring closest to the ester substituent.
What is game theory?from bath.ac.uk
Game theory is a branch of applied maths that allows us to model and analyse zero-sum games between intelligent rational decision makers. Connect 4 is an example of a game that can be modelled and “solved” using game theory.
Overview
History
Benzocaine was first synthesized in 1890 by the German chemist Eduard Ritsert (1859–1946), in the town of Eberbach and introduced to the market in 1902 under the name "Anästhesin".
Medical uses
Benzocaine is indicated to treat a variety of pain-related conditions. It may be used for:
• Local anesthesia of oral and pharyngeal mucous membranes (sore throat, cold sores, mouth ulcers, toothache, sore gums, denture irritation)
• Otic pain (earache)
Side effects
Benzocaine is generally well tolerated and non-toxic when applied topically as recommended.
However, there have been reports of serious, life-threatening adverse effects (e.g., seizures, coma, irregular heart beat, respiratory depression) with over-application of topical products or when applying topical products that contain high concentrations of benzocaine to the skin.
Overapplication of oral anesthetics such as benzocaine can increase the risk of pulmonary aspir…
Pharmacology
Pain is caused by the stimulation of free nerve endings. When the nerve endings are stimulated, sodium enters the neuron, causing depolarization of the nerve and subsequent initiation of an action potential. The action potential is propagated down the nerve toward the central nervous system, which interprets this as pain. Benzocaine acts to inhibit the voltage-dependent sodium channels (VDSCs) on the neuron membrane, stopping the propagation of the action potential.
Chemistry
Benzocaine is the ethyl ester of p-aminobenzoic acid (PABA). It can be prepared from PABA and ethanol by Fischer esterification or via the reduction of ethyl p-nitrobenzoate. Benzocaine is sparingly soluble in water; it is more soluble in dilute acids and very soluble in ethanol, chloroform, and ethyl ether. The melting point of benzocaine is 88–90 °C, and the boiling point is about 310 °C. The density of benzocaine is 1.17 g/cm .
Veterinary medicine
A bath solution of benzocaine has been used to anesthetize amphibians for surgery.
External links
• "Benzocaine". Drug Information Portal. U.S. National Library of Medicine.