New answers tagged

2

This does indeed work. One such reference includes US patent 3696080A in which propionaldehyde is reacted with dimethylamine to give the N,N-acetal as shown in the figure below. The described reaction procedure involves cooling both reagents to $\pu{-78^\circ C}$ before addition, letting the temperature rise to around $\pu{-35^\circ C}$ at which point ...


0

Number the carbon atoms from 1 to 7 in order from left to right. When a carbanion function forms at carbon atom #3, it can then attack either carbon atom #1 or carbon atom #7. To get carbon #7 into position for the latter attack, however, you need a bond rotation around the bond between carbon atoms 4 and 5. That could become restricted if a carbanion ...


-3

When you compare the ortho and para positions, both have a higher electron density vs the rest of the positions. So for now, we can attack both the positions. Now, look at the position of the alcohol group. The alcohol group pulls electrons by the inductive effect so it will decrease the electron density at the ortho position in comparison to the ortho ...


-1

An Alternate view, NOT mechanistically correct, but just to help remember it is that NO+ is a weaker nucleophile than NO2- as in one of the resonating structures of NO+, all the atoms have a complete octet and therefore it is relatively more stable. So, NO2- being the stronger nucleophile attacks.


2

Grignard reagent is an organomagnesium halide in which magnesium and halide bond is ionic. It is not like magnesium is always inserted in between carbon and halogen bond. Once formed, magnesium-carbon bond should be configurationally stable under the conditions of the reaction (Ref.1), and is polar covalent (at least partially) so that $\ce{Mg}$ has to be ...


2

Your thought is actually happening in real life. Petrolium industry uses the same concept except for polymerizing ethene (may be that also used to get higher alkanes). Fluid Catalytic Cracking (FCC) is one of the most important conversion processes used in petroleum refineries. FCC (see the schematic diagram below)) is widely used to convert the high-boiling,...


1

The Reimer–Tiemann reaction will give a mixture of products unless the formation of one product is highly disfavoured. The Kürti-Csakó notes in its introductory paragraph on the Reimer–Tiemann:[1] the regioselectivity is not high, but ortho-formyl products tend to predominate; The statement already hints at a product mixture being obtained. To further show ...


1

My initial guess for the product was Phloroglucinol, or 1,3,5-trihydroxybenzene1,2 Belskaya et al.3 says that 1,3,5-triaminobenzene can be formed, but it can eventually be hydrolyzed to Phloroglucinol The sources mention decarboxylation as the mechanism. Note that it is the trihydroxylamine 10 that is getting decarboxylated here. The mechanism becomes ...


4

The course of the reaction depends on whether or not a proton source other than ammonia is present. In the absence of an alcohol (ethanol, tert-butanol) the α-dione 1 adds an electron from sodium to give a resonance stabilized radical anion 2. A second electron is added to afford enediolate 3. [This is the same species formed with sodium in the acyloin ...


-1

$\ce{H2CO3}$ and $\ce{NaCl}$ do not react. The sodium chloride provides a surface with high friction which allows the $\ce{CO2}$ to transform into a gas. The same thing happens with mentos and fizzy drinks. One might say that the sodium chloride is serving as a catalyst for the transformation of $\ce{H2CO3}$ into $\ce{H+(aq)}$ and $\ce{CO2(g)}$.


3

The major product in this case is favoured due to Steric hindrance in the product. Drawing the full structure of the molecule in the reaction makes this clearer We can compare the degree of steric hindrance in the major product and the minor product by using A-values. The Wikipedia article gives the following A-values for common substituents: $$\begin{array}...


5

Often, yes; but sometimes not, and generalisations like that often don't work in organic chemistry. It's a better idea to understand why there's a correlation between "light" and "radical reactions". One way of generating radicals is by breaking bonds, and one way of breaking bonds is to use light. Of course, this only really works for ...


1

There is variable information in textbooks about the reaction of silicon with water. Unlike all common allotropic forms of carbon, silicon surface or dust can react with water at elevated temperatures to form oxide layer or orthosilic acid. Oxidation of Silicon by High-Pressure Steam by Joseph R. Ligenza Original Paper ABSTRACT: The oxidation of silicon by ...


4

This reaction was conducted using a 3- to 5-fold excess of ethyl cyanoacetate (ECA) and KOH over the arylnitro compounds in dimethylformamide (DMF). It is also important to realize that most KOH is 15% water, which allows for a source of protons in this basic medium. Steps 1 --> 3 (Scheme 1) illustrate a possible route to nitrone 4. In so doing the ECA ...


2

Your scheme is one of sequential reactions. The chain reaction has feedback so that one to two reactions occur repeatedly until the reactants are all consumed. The general scheme is shown in the diagram where $R\cdot$ represents any radical species ( H or Cl in Maurice's answer) and $\alpha$ has to be at least 1 for species $R\cdot$ to continue the chain ...


1

1. Electrophilicity of the triple bond Hard-soft acid-base theory ties in with this question. The general trends in nucleophile-electrophile reactivity show that hard (highly charge dense) nucleophiles have a tendency to react well with hard electrophiles, and soft (low charge density) nucleophiles with soft electrophiles. This relationship is due to two ...


1

A good example of chain rection is the photochloration of $\ce{H_2}$ by $\ce{Cl_2}$. The first reaction is due to the first photon striking a chlorine molecule, producing two chlorine atoms Cl. Then each Cl atom reacts with a $\ce{H_2}$ molecule producing one HCl and one H atom. This H atom reacts with another $\ce{Cl_2}$ producing one HCl and a new Cl atom ...


5

I'd say, yes it is possible. The pioneering work on interconversion reactions of cyclobutyl, cyclopropylcarbinyl, and allylcarbinyl derivatives has been done by John D. Roberts and coworkers (Ref.1). In these works, they have checked reactions under both $\mathrm{S_N1}$ and $\mathrm{S_N2}$ conditions. They have observed the reactions expected to involve ...


5

Aniruddha Deb gave an excellent answer to your question. Yet, there is another important point of differences on two Friedel-Craft processes: Alkylation vs acylation. I admit that rearrangement is the major drawback on alkylation process (using alkyl halides with a catalyst). However, another fact is you cannot stop the reaction after monoalkylation. The ...


9

Initially one would assume that cumene (isopropyl benzene) would be the major product. However, kinetic control does have a say in this reaction, according to Gilman and Means.1 At - 2°, n-propyl bromide with benzene and aluminum chloride gave n-propylbenzene, identified as its sulfonamide. Genvresse (6) obtained both n-propylbenzene and isopropylbenzene by ...


8

I agreed with andselisk's answer. Yet, Ambident Substrates are not limited to March’s given examples in that answer. A substrate, which can be consecutively acted either as an electrophile of a nucleophile is also called ambident substrate (Ref.1). One of the best example is acetaldehyde or propanaldehyde in aldol condensation: In 2002, Barbas III & ...


10

There is a subsection in March’s Advanced Organic Chemistry [1, pp. 450–451] that provides a straightforward definition and a couple of examples: 10.G.viii. Ambident Substrates Some substrates (e.g., 1,3-dichlorobutane) can be attacked at two or more positions, and these may be called ambident substrates. In the example given, there happen to be two leaving ...


1

On 'heating' in the 'earth atmosphere' elemental magnesium in what form? This is, in my assessment, actually quite a good chemistry essay type question, because required clarification on the chemistry is likely needed. This arises from noted ambiguities, as for example, with respect to the intensity of the heat applied, the form of Mg present (as a powder or ...


-2

It is halogenation by free radical mechanism. In UV radiations halogen gas produces two halogen free radical which can cause allylic substitutions !


5

I don't think that composition is the answer because on an average, the atmosphere of Earth has more Nitrogen than Oxygen, so I think that the answer may be temperature. Indeed, temperature is an important factor for this reaction and the reaction carries at a specific temperature. It was intensively studied in the late 19th century$\ce{^{[2]}}$. It was ...


19

A large pile of grey magnesium powder, when lit in air, produces a smouldering pile which cools down to reveal a crusty white solid of magnesium oxide. However, if you break apart the mound, you can find something quite strange in the middle - a clearly brownish powder that wasn't there before. Seeing is believing! The author of the video also has a clever ...


4

Nicolau Saker Neto's answer does a more accurate job of answering the question. Do give that answer a read as well. Exactly the same question was pubilshed in University of Waterloo's Chem13 magazine. More details can be found in the link but the conclusion was: Given that no evidence of $\ce{Mg3N2}$ formation could be found, it appears that the hydration ...


2

First, a review of the underlying chemistry per an educational source: A clock can be formed from molecules that react at a rate from the time the chemicals are mixed to the time the reaction occurs. Explanation: There are two forms of iodine: Element form (Iodine): I2 + starch -------> blue Ion form (Iodide): I- + starch --------> colorless There are ...


1

Note that whether the forward or reverse reaction is favorable depends entirely on the relative magnitudes of Q and K (the reaction quotient versus the equilibrium constant): $$\begin{align} Q&>K \rightarrow \text{reactants favored} \\ K&>Q \rightarrow \text{products favored} \end{align}$$ Next, consider that when you declare a value for $\...


4

Not really. As long as you are in solution (=unreacted monomer or solvent), it makes no difference if the reactive chain end is diffusing slow or fast. The monomer molecules come by at the same rate. The mobile chain end would help against a local depletion of monomer, but once your mixture gets so viscous that this could happen, neither a long or a short ...


6

Kornblum1 demonstrated that nitrocyclohexane 3 was the major isolable product from the reaction of iodocyclohexane 1 and silver nitrite. Earlier work by Rosanow2 (1915) claimed the additional formation of tertiary nitro compound 7, a result that Kornblum did not confirm. If indeed nitrocyclopentane 7 did form, a ring contraction is required. Ring contraction ...


0

Your mechanism is almost correct. In your first intermediate, you have a red arrow in the wrong place. Since this ring is opening up, you want the arrow showing movement of the ring electrons (those between the lower carbonyl and the ring oxygen). Ideally, you would show those electrons becoming the new CO double bond of the aluminum carboxylate.


-1

Electronic effects govern in the order Resonance/Mesomeric > Hyperconjugation > inductive With this I mean that +M will dominate over -I Therefore the order of reactivity towards nucleophilic substitution is 4>1>2>3


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