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3 years ago

What reaction conditions most effectively convert a carboxylic acid to a methyl ester

Chemistry

2 answers:

ycow [4]3 years ago

4 0

Answer:

Fischer Esterification

Explanation:

Fischer esterification or Fischer-Speier esterification is a carboxylic esterification reaction that uses an inorganic acid as a catalyst, mainly sulfuric acid (H2SO4).

The carboxylic acids are usually too weak acids, so they have little tendency to yield the proton (H +) that they lose in the esterification.

A stronger acid, such as sulfuric acid, behaves like a proton donor and facilitates the esterification reaction.

First, sulfuric acid injects a proton into the carboxyl group

The alcohol molecule, R’-OH, has an electron-rich oxygen atom, is attracted to the protonated carboxylic structure

This complex is not very stable and stabilizes towards the most favorable energy molecule, which is the ester, releasing a water molecule and a proton (H +). The proton is then used to regenerate sulfuric acid

dem82 [27]3 years ago

4 0

Answer: The convenient and efficient sonochemical method for methyl esterification of carboxylic acids reaction conditions are ;

• catalyzation by polymer-supported triphenylphosphine (0.1 eq. PS-PPh3)

• in the presence of 2,4,6-trichloro-1,3,5-triazine (1.0 eq. TCT) and Na2CO3 (2.0 eq. )

• Temperature 50°C for 10 - 30 mins

Explanation:

Methyl esters of various carboxylic acids bearing reactive hydroxyl groups as well as acid- or base-labile functionalities could be rapidly prepared within short times in good to excellent yields in high purities without column chromatography.

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3 years ago

What is the equation between aqueous sodium carbonate and dilute hydrochloric acid

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2 years ago

Draw a lewis structure for ketene, c2h2o, which has a carbon–carbon double bond

MrMuchimi

Visual representation of covalent bonding indicating the valence shell electrons in the molecule, lines represents the shared pair of electron and pair of electrons that are not involved in bonding are represented as dots(lone pairs) are known as Lewis structures.

Compound formation takes place in order to complete the octet of each element that is according to octet rule, each atom forms bond with other atom in order to complete their octet that is to get eight electrons in its valence shell and attain stability.

An organic compound of the form $R^{'}R^{''}C=C=O$ is known as ketene.

The given ketene is $C_2H_2O$ .

The number of valence electron of:

$C = 4$

$H = 1$

$O = 6$

The number of valence electrons in $C_2H_2O$ = $2\times 4+2\times 1+1\times 6 =16$

2 electrons are involved in each single bond between carbon and hydrogen and 4 electrons are involved in each double bond formed between carbon-carbon and carbon-oxygen. Hence, the total number of electrons involved in bond formation are 12 and rest 2 pair of electrons are present on oxygen as lone pair of electrons.

Therefore, the attached image is the Lewis structure of $C_2H_2O$ .

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3 years ago

Excess magnesium reacts with 165.0 grams of hydrochloric acid in a single displacement reaction.

JulsSmile [24]

Answer:

The volume of hydrogen gas produced will be approximately 50.7 liters under STP.

Explanation:

Relative atomic mass data from a modern periodic table:

H: 1.008;
Cl: 35.45.

Magnesium is a reactive metal. It reacts with hydrochloric acid to produce

Hydrogen gas $\rm H_2$ , and
Magnesium chloride, which is a salt.

The chemical equation will be something like

$\rm ?\;Mg\;(s) + ?\;HCl \;(aq)\to ?\;H_2 \;(g)+ [\text{Formula of the Salt}]$ ,

where the coefficients and the formula of the salt are to be found.

To determine the number of moles of $\rm H_2$ that will be produced, first find the formula of the salt, magnesium chloride.

Magnesium is a group 2 metal. The oxidation state of magnesium in compounds tends to be +2.

On the other hand, the charge on each chloride ion is -1. Each magnesium ion needs to pair up with two chloride ions for the charge to balance in the salt, magnesium chloride. The formula for the salt will be $\rm MgCl_2$ .

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ ?\;MgCl_2\;(aq)$ .

Balance the equation. $\rm MgCl_2$ contains the largest number of atoms among all species in this reaction. Start by setting its coefficient to 1.

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ {\bf 1\;MgCl_2}\;(aq)$ .

The number of $\rm Mg$ and $\rm Cl$ atoms shall be the same on both sides. Therefore

$\rm {\bf 1\;Mg}\;(s) + {\bf 2\;HCl}\;(aq) \to ?\;H_2 \;(g)+ {1\;\underset{\wedge}{Mg}\underset{\wedge}{Cl_2}}\;(aq)$ .

The number of $\rm H$ atoms shall also conserve. Hence the equation:

$\rm {1\;Mg}\;(s) + {2\;\underset{\wedge}{H}Cl}\;(aq) \to {\bf 1\;H_2 \;(g)}+ {1\;MgCl_2}\;(aq)$ .

How many moles of HCl are available?

$M(\rm HCl) = 1.008 + 35.45 = 36.458\;g\cdot mol^{-1}$ .

$\displaystyle n({\rm HCl}) = \frac{m(\text{HCl})}{M(\text{HCl})} = \rm \frac{165.0\;g}{36.458\;g\cdot mol^{-1}} = 4.52576\;mol$ .

How many moles of Hydrogen gas will be produced?

Refer to the balanced chemical equation, the coefficient in front of $\rm HCl$ is 2 while the coefficient in front of $\rm H_2$ is 1. In other words, it will take two moles of $\rm HCl$ to produce one mole of $\rm H_2$ . $\rm 4.52576\;mol$ of $\rm HCl$ will produce only one half as much $\rm H_2$ .

Alternatively, consider the ratio between the coefficient in front of $\rm H_2$ and $\rm HCl$ is:

$\displaystyle \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}$ .

$\displaystyle n(\text{H}_2) = n(\text{HCl})\cdot \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}\;n(\text{HCl}) = \rm \frac{1}{2}\times 4.52576\;mol = 2.26288\;mol$ .

What will be the volume of that many hydrogen gas?

One mole of an ideal gas occupies a volume of 22.4 liters under STP (where the pressure is 1 atm.) On certain textbook where STP is defined as $\rm 1.00\times 10^{5}\;Pa$ , that volume will be 22.7 liters.

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.4\;L\cdot mol^{-1} = 50.69\; L$ , or

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.7\;L\cdot mol^{-1} = 51.37\; L$ .

The value "165.0 grams" from the question comes with four significant figures. Keep more significant figures than that in calculations. Round the final result to four significant figures.

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3 years ago

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Lynna [10]

True.

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3 years ago

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