Can we turn nouns into adverb by adding に?


> しかし、 **期待を胸に** 中学校に赴任すると、理想と現実は大きくかけ離れていました。

> 加藤さんは **大切な手紙を手に** 再び「パナマ」へ向かいます。

> 彼女は **手紙を手に** 、階下へ降りてきた。

Is に turning these nouns into adverbs?




None of your examples are being used as adverbs.

Your first example is the fault of lack of comma usage. Read this way:

> 「しかし、期待を胸に、中学校に赴任すると、理想と現実は大きくかけ離れていました。」 But, with my hope in my heart, I
> transferred to junior-high, whereupon my dreams and reality drifted apart
> dramatically. - - - - 胸に = in my heart

The other two examples are the same as far as using 手に (in hand), with one of
them simply not containing a comma.

> 「加藤さんは大切な手紙を手に（、）再び「パナマ」へ向かいます。」  
>  Kato took the important letter in hand, and headed again for Panama.
>
> 「彼女は手紙を手に、階下へ降りてきた。」 She took the letter in hand, and came down to the
> hallway.

Rules for use of commas are not quite as strict as in English. Usage also
varies by writer. Often, where we would expect to see a break in the sentence
there is none. Learning how to parse these types of sentences takes time.

If you do want to change nouns into adjectives or adverbs, use ～的 or ～的に as
detailed [here](http://learnjapanese.becauseofdreams.com/2017/08/10/how-to-
turn-nouns-into-adjectives-and-adverbs-with-%E7%9A%84-%E3%81%A6%E3%81%8D/).

Also recommend that you get used to using「」 for open/close quotes in Japanese.

