Let given ring $R$ of finite rank. Is it true that for all primes $p$ large enough modules $Der_{\mathbb{Z}}(R/pR) = \{0\}$?
For every ring we define $Der_{\mathbb{Z}}(R)$ as set of linear operators $D : R\to R$, where $\forall a, b\in R, D(ab) = aD(b) + bD(a)$.
I can prove this in case $R/pR$ without nillpotentnilpotent elements:
In this case for enyany $r\in R\setminus\{0\}$, $D\in Der_{\mathbb{Z}}(R/pR)$ and any prime $p > n = rk(R)$, it is well known that $\exists f = a_0 +...+ a_qx^q\in \mathbb{Z}[x] : f(r) = 0$,$$\exists f = a_0 +...+ a_qx^q\in \mathbb{Z}[x] : f(r) = 0$$ with $\deg f\leq n$,$$\deg f\leq n$$ Moreover if $p|a_0,...,a_q$ then we can dactor $f$ by $p$$p|f$, so we can think that $f\not= 0\in\mathbb{Z}_p[x]$.
Let $\{P_i\}_{1\leq i\leq k}$ arebe different primes in $\mathbb{Z}_p[x]$, such that $f = P_1^{w_1}...P_k^{w_k}\in\mathbb{Z}_p[x]$.
Let $R/pR$ be without nillpotent elementsnilpotents so that $g = P_1...P_k, g(r) = 0$$g = P_1...P_k\implies g(r) = 0$.
So $D(g(r)) = g'(r)D(r) = g(r)D(r) = 0$, $gcd(g, g') = 1$, so $D(r) = 0$. $\Box$