[化学論文のための英語講座] 第74回：前置詞 研究論文でよく使う慣用句 Prepositions: Common Idioms used in Research Papers
2025年1月28日
(English version is here.)
英語で前置詞は100以上あり、複合前置詞も多いですが、研究論文を書くために暗記すべき慣用句もいくつかあります。前置詞を間違えたら意味が変わる場合もあります。例を見てみましょう。以下はどう違うでしょうか？
和訳：反応は空気中で行われた。
1. The reaction was conducted under air.
2. The reaction was conducted in air.
3. The reaction was conducted in the air.
1, 2 は同じ意味です。反応は空気中で行われた。
「air」は「空気」ですが「the air」は「ある空気」または「空、天」という意味があります。「in the air」は「空気中」という意味もありますが、普段は「空に」という意味で使います。3は「反応は空気中で行われた」とも訳すことができますが、「反応は空（天）に行われた」という印象を与えます。３の例文をよりはっきりさせる場合には「The reaction was conducted under ambient air.」または「The reaction was conducted under ambient atmosphere.」とします。
補足：「in the air」は「まだ決めていない」という意味もあります。
Conditions を書く場合には in と under、どちらが良いでしょうか？
和訳：反応は乾燥条件で良好に進行した。
4. The alkylation proceeded well in dry conditions.
5. The alkylation proceeded well under dry conditions.
4, 5 はどちらでも正しいです。
Yield の適切な前置詞は何でしょうか。
和訳：アルデヒドは良好な収率で生成した。
6. The aldehyde was produced in good yield.
和訳：目的生成物が良好な収率で得られた。
7. The desired product was obtained with good yield.
有機化学者は in (good) yield をよく使いますが、with (good) yield も正しいです。
和訳：ヨウ化アリールは金属中心に酸化的に付加した。
8. The aryl iodide added oxidatively to the metal centre.
付加反応の場合は普通「to」を使います。「A adds to B」
注意！前置詞がない場合もあります。
和訳：求核性水酸化物はカルボニルを攻撃する。
9. The nucleophilic hydroxide attacks the carbonyl.
attackは他動詞なので前置詞は要りません。
乾燥剤を使う場合には、どの前置詞が適切でしょうか？
和訳：溶媒は水素化カルシウムで乾燥させた。
10. The solvent was dried with calcium hydride.
11. The solvent was dried over calcium hydride.
12. The solvent was dried in the presence of calcium hydride.
10, 11, 12 は全部正しいですが、11 (over)が頻繁に使われます。
比較するときには前置詞が必要です。
和訳：塩化物と比較すると、ヨウ化物はより反応性が高い。
13. In comparison with the chloride, the iodide is more reactive.
14. In comparison to the chloride, the iodide is more reactive.
15. Compared to the chloride, the iodide is more reactive.
16. In comparison, the iodide is more reactive than the chloride.
13-16 はすべて正しいです。
近寄る「approach」は、場合によっては前置詞を使います。「approach from」はよく使いますが「approach to」は誤りです。
和訳：求核剤は反対側に近づく。
17. The nucleophile approaches the opposite side.
和訳：求核剤はカルボニル基のβ面に近づく。
18. The nucleophile approaches the β face of the carbonyl moiety.
和訳：求核剤が反結合性軌道に近づく。
19. The nucleophile approaches to the anti-bonding orbital.
17, 18 は正しいです。19 は間違いです。ここで前置詞「to」は不要です。
復習 with/by
第3回：受動態で「with/by」の使い分けに触れましたが、ちょっと復習してみましょう。
受動態で動作主をはっきりさせる場合には前置詞が必要です。動作主が人間の時は「by」を使います。動作主が手法または操作のような、動作を示す名詞の場合にも「by」を用います。一方、動作主が機械または物であれば、「with」をよく使います。「with」を使うと、誰かが意図や目的を持って利用することを示唆しますので、意志を持っていない動作主である機械や物を述べるとき普通「by」を使いません。しかし、普遍的事実について述べるときは人間の意図がなくても「by」を利用する場合があります。
和訳：アルデヒド基の存在は赤外分光法により確認された。
20. The presence of the aldehyde moiety was confirmed by IR spectrometry.
和訳：スペクトルは改良型赤外分光計によって得られた。
21. The spectra were acquired with a modified IR spectrometer.
和訳：反応は外来水によって触媒されたと思われる。
22. The reaction appears to be catalysed by adventitious water.
20. では「IR spectrometry」は手段です。21. では「IR spectrometer」は機械です。22. では「adventitious water」は人間の意図とは関係なく作用するので、独立動作主です。
「Followed by」の二重の意味を覚えていますか？
和訳：反応の進行はガスクロマトグラフィーで追跡した。
23. Reaction progress was followed by gas chromatography.
和訳：炭酸水素ナトリウムを加え、次に撹拌した。
24. Addition of sodium bicarbonate was followed by stirring.
例文23では「followed by」は「追跡する」の意味です。例文24では「followed by」は「次に」の意味です。
次回は前置詞に関しての補足です。
Prepositions: Common Idioms used in Research Papers
There are over 100 prepositions in English, including many compound prepositions, and there are also numerous idiomatic expressions that should be committed to memory for writing research papers. Using a preposition incorrectly can change the meaning. Let us look at a few examples. What is the difference among the following?
1. The reaction was conducted under air.
2. The reaction was conducted in air.
3. The reaction was conducted in the air.
1 and 2 have the same meaning. The reaction was conducted in an atmosphere of air. Air, of course, refers to the gas mixture that comprises the terrestrial atmosphere. The air, however, refers to a definite portion of this gas or the sky. In the air can mean in an atmosphere of air, but it usually means in the sky or in the atmosphere in general. 3 can be interpreted to mean the reaction was conducted in an air atmosphere, but it also gives the impression of the reaction was conducted in the sky. 3 can be written more explicitly as the reaction was conducted under ambient air or the reaction was conducted under ambient atmosphere.
Note: In the air can also mean not yet decided.
When writing conditions, which is better, in or under?
4. The alkylation proceeded well in dry conditions.
5. The alkylation proceeded well under dry conditions.
4 and 5 are both correct.
What is the appropriate preposition to use with yield?
6. The aldehyde was produced in good yield.
7. The desired product was obtained with good yield.
Organic chemists often use in (good) yield, but with (good) yield is also correct.
8. The aryl iodide added oxidatively to the metal centre.
In the case of addition reactions, to is generally used. (A adds to B)
Note: There are also cases in which prepositions are not used.
9. The nucleophilic hydroxide attacks the carbonyl.
Here, attack is transitive and takes no preposition.
When using desiccants, what preposition(s) should be used?
10. The solvent was dried with calcium hydride.
11. The solvent was dried over calcium hydride.
12. The solvent was dried in the presence of calcium hydride.
10, 11 and 12 are all correct, but 11 over is regularly used.
When comparing, prepositions are necessary.
13. In comparison with the chloride, the iodide is more reactive.
14. In comparison to the chloride, the iodide is more reactive.
15. Compared to the chloride, the iodide is more reactive.
16. In comparison, the iodide is more reactive than the chloride.
13-16 are all correct.
The verb approach takes a preposition depending on the use. Approach from is often used but approach to is a mistake.
17. The nucleophile approaches the opposite side.
18. The nucleophile approaches the β face of the carbonyl moiety.
19. The nucleophile approaches to the anti-bonding orbital.
17 and 18 are correct, but 19 is incorrect. Here the preposition to is unnecessary.
Review: with/by
In Part 3: Passive Voice, we touched on the use of with and by, but let us review briefly. When clarifying the actor in passive voice, a preposition is necessary. When the actor is human, by is used. When the actor is a technique or operation, by is used. On the other hand, when the actor is a machine or object, with is often used. Using with suggests that someone is using it with will or purpose, so by is not usually used when describing a machine or object that has no will. However, when describing universal realities, by is used even without human will.
20. The presence of the aldehyde moiety was confirmed by IR spectrometry.
21. The spectra were acquired with a modified IR spectrometer.
22. The reaction appears to be catalysed by adventitious water.
In 20 IR spectrometry is a technique. In 21 IR spectrometer is a machine. In 22 adventitious water behaves regardless of human will and thus is an independent actor.
Do you remember the two meanings of followed by?
23. Reaction progress was followed by gas chromatography.
24. Addition of sodium bicarbonate was followed by stirring.
In 23 followed by can be replaced with pursued by. In 24 followed by can be replaced with succeeded by.
At next time, we will post about supplemental on prepositions.