Ester compounds $\bf A$ and $\bf B$ undergo a condensation reaction in a solution of sodium ethoxide in ethanol. After the reaction, the mixture is treated with water, and one of the products is $\bf C$; the spectroscopic analysis results are shown in the table below:

| Compound |  $\rm ^1H-NMR (\delta, ppm)$                  |
| :----- |:------------------------------- |
| $\bf A$      | $\rm 8.03 (1H, s), 4.22 (2H, q), 1.29 (3H, t)$ |
| $\bf B$       | $\rm 4.12 (2H, q), 2.04 (3H, s), 1.26 (3H, t)$ |
| $\bf C$      | $\rm 8.82 (3H, s), 4.42 (6H, q), 1.41 (9H, t)$ |

Which of the following statements is correct:
酯类化合物$\bf A$、$\bf B$在乙醇钠的乙醇溶液中发生缩合反应,反应后用水处理,产物之一为$\bf C$;其谱学分析结果如下表所示:

| 化合物 |  $\rm ^1H-NMR (\delta, ppm)$                  |
| :----- |:------------------------------- |
| $\bf A$      | $\rm 8.03 (1H, s), 4.22 (2H, q), 1.29 (3H, t)$ |
| $\bf B$       | $\rm 4.12 (2H, q), 2.04 (3H, s), 1.26 (3H, t)$ |
| $\bf C$      | $\rm 8.82 (3H, s), 4.42 (6H, q), 1.41 (9H, t)$ |

下列说法正确的是：
All other options are incorrect
$\bf B$ Acid hydrolysis produces gas
$\bf A,B,C$ The hydrolysis products under acidic conditions are completely different.
$\bf A,B,C$ all belong to the $C$ point group
$\bf C$ is capable of self-condensation.
$\bf A，B$ The product of a single condensation reaction occurring between them is only one type.
其他选项均不正确
$\bf B$酸性条件下水解产生气体
$\bf A,B,C$酸性条件下水解的产物完全不同
$\bf A,B,C$均属于C点群
$\bf C$能够自缩合
$\bf A，B$发生一次缩合的产物只有一种
Analyze the proton NMR spectrum:
Since they are all ester compounds, the alcohol before condensation has at least one methyl group; therefore, for $\bf A,B,C$, their $
\rm 3H,t$ peaks are all methyl peaks, and the high-field $\rm 2H,q$ peak is methylene, suggesting that these five hydrogens constitute an ethyl group, so $\bf A,B,C$ all produce ethanol after hydrolysis. Option C is incorrect.

<Checkpoint>[$\rm 3H,t$ peaks are all methyl peaks, and the high-field $\rm 2H,q$ peak is methylene, constituting an ethyl group](1)</Checkpoint>

<Checkpoint>[$\bf A,B,C$ all produce ethanol after hydrolysis](1)</Checkpoint>

Observing the proton NMR spectrum of $\bf C$, it has a low-field peak, which can be speculated to be aromatic hydrogen. $\bf C$ has three ethyl groups, which can be speculated to be three ethyl ester groups and three aromatic hydrogens, so $\bf C$ contains a benzene ring; since the chemical shifts of the aromatic hydrogens are the same, their chemical environments are also the same, $\bf C$ is actually meta-tris(ethyl ester)benzene, with the structure of; O=C(C1=CC(C(OCC)=O)=CC(C(OCC)=O)=C1)OCC

<Checkpoint>[$\bf C$ is actually meta-tris(ethyl ester)benzene, with the structure of：O=C(C1=CC(C(OCC)=O)=CC(C(OCC)=O)=C1)OCC](1)</Checkpoint>

$\bf A$ contains only one low-field hydrogen, which is unlikely to be aromatic hydrogen, considering it to be aldehyde hydrogen; therefore, $\bf A$ is ethyl formate, with the structure of O=C([H])OCC

<Checkpoint>[$\bf A$ is ethyl formate, with the structure of O=C([H])OCC](1)</Checkpoint>

$\bf B$ does not contain low-field hydrogen but has an extra $\rm 3H,s$ peak, which is obviously the methyl group at the alpha position of the ester group. Therefore, $\bf B$ is ethyl acetate, with the structure of O=C(C)OCC

<Checkpoint>[$\bf B$ is ethyl acetate, with the structure of O=C(C)OCC](1)</Checkpoint>

$\bf B$ produces acetic acid and ethanol after hydrolysis, option B is incorrect. Obviously, $\bf C$ belongs to the D point group, option D is incorrect. $\bf C$ has no α-H and cannot self-polymerize, option E is incorrect. $\bf A$ has no α-H, so there is only one ester condensation product, option F is correct.

<MultiModal>![Structure of $\bf C$: O=C(C1=CC(C(OCC)=O)=CC(C(OCC)=O)=C1)OCC; Structure of $\bf A$: O=C([H])OCC; Structure of $\bf B$: O=C(C)OCC](/media/uploads/42fcf725-d9b4-4e33-8d56-24e31c209220.png)</MultiModal>
对氢谱进行分析：
由于均为酯类化合物，其缩合前的醇至少具有一个甲基；因此对于$\bf A,B,C$，其$
\rm 3H,t$峰均为甲基峰，$\rm 2H,q$的高场峰为亚甲基，可以想到这五个氢构成一个乙基，因此$\bf A,B,C$水解后均产生乙醇。选项C错误。

<Checkpoint>[$ \rm 3H,t$峰均为甲基峰，$\rm 2H,q$的高场峰为亚甲基，构成一个乙基](1)</Checkpoint>

<Checkpoint>[$\bf A,B,C$水解后均产生乙醇](1)</Checkpoint>

观察$\bf C$的氢谱，其拥有低场的峰，可以猜测为芳香氢。$\bf C$拥有三个乙基，可以猜测为三个乙酯基和三个芳香氢，因此$\bf C$含有苯环；由于芳香氢化学位移相同，其化学环境也相同，$\bf C$实际为间三苯乙酯，结构为；O=C(C1=CC(C(OCC)=O)=CC(C(OCC)=O)=C1)OCC

<Checkpoint>[$\bf C$实际为间三苯乙酯，结构为：O=C(C1=CC(C(OCC)=O)=CC(C(OCC)=O)=C1)OCC](1)</Checkpoint>

$\bf A$只含有一个低场氢，不太可能为芳香氢，考虑为醛氢；因此$\bf A$为甲酸乙酯，结构为O=C([H])OCC

<Checkpoint>[$\bf A$为甲酸乙酯，结构为O=C([H])OCC](1)</Checkpoint>

$\bf B$不含有低场氢但多出了一个$\rm 3H,s$峰，明显为酯基α位的甲基。因此$\bf B$为乙酸乙酯，结构为O=C(C)OCC

<Checkpoint>[$\bf B$为乙酸乙酯，结构为O=C(C)OCC](1)</Checkpoint>

$\bf B$水解产生乙酸和乙醇，选项B错误。很明显$\bf C$为D点群，选项D错误。$\bf C$没有α-H，无法自聚，选项E错误。$\bf A$没有α-H，因此酯缩合产物只有一种，选项F正确。

<MultiModal>![$\bf C$结构为；O=C(C1=CC(C(OCC)=O)=CC(C(OCC)=O)=C1)OCC；$\bf A$结构为O=C([H])OCC；$\bf B$结构为O=C(C)OCC](/media/uploads/42fcf725-d9b4-4e33-8d56-24e31c209220.png)</MultiModal>