diff --git a/src/rxn/chemutils/miscellaneous.py b/src/rxn/chemutils/miscellaneous.py
index b398f7f..ad4d764 100644
--- a/src/rxn/chemutils/miscellaneous.py
+++ b/src/rxn/chemutils/miscellaneous.py
@@ -15,6 +15,7 @@
     sort_multicomponent_smiles,
 )
 from .reaction_equation import (
+    ReactionEquation,
     apply_to_compound_groups,
     apply_to_compounds,
     sort_compounds,
@@ -251,3 +252,17 @@ def get_individual_compounds(any_smiles: str) -> List[str]:
         # We interpret it as a multicomponent SMILES.
         # We use "~" as a fragment bond even if it is not actually needed.
         return multicomponent_smiles_to_list(any_smiles, fragment_bond="~")
+
+
+def merge_reactions(*reactions: ReactionEquation) -> ReactionEquation:
+    """Merge several reactions into one.
+
+    Useful when ReactionEquation is used to store partial equations."""
+    reactants = []
+    agents = []
+    products = []
+    for reaction in reactions:
+        reactants.extend(reaction.reactants)
+        agents.extend(reaction.agents)
+        products.extend(reaction.products)
+    return ReactionEquation(reactants=reactants, agents=agents, products=products)
diff --git a/tests/test_miscellaneous.py b/tests/test_miscellaneous.py
index 32aaf15..e7cefd0 100644
--- a/tests/test_miscellaneous.py
+++ b/tests/test_miscellaneous.py
@@ -12,10 +12,12 @@
     equivalent_smiles,
     get_individual_compounds,
     is_valid_smiles,
+    merge_reactions,
     remove_chiral_centers,
     remove_double_bond_stereochemistry,
     sort_any,
 )
+from rxn.chemutils.reaction_equation import ReactionEquation
 
 
 def test_equivalent_smiles() -> None:
@@ -217,3 +219,25 @@ def test_get_individual_compounds() -> None:
         "C",
         "B",
     ]
+
+
+def test_merge_reactions() -> None:
+    # No reaction given
+    assert merge_reactions() == ReactionEquation([], [], [])
+
+    # one reaction
+    r1 = ReactionEquation(["A", "B"], ["C"], ["D"])
+    assert merge_reactions(r1) == r1
+
+    # two reactions
+    r2 = ReactionEquation(["F"], ["G"], [])
+    assert merge_reactions(r1, r2) == ReactionEquation(
+        ["A", "B", "F"], ["C", "G"], ["D"]
+    )
+
+    # more than two reactions
+    r3 = ReactionEquation([], ["H"], [])
+    r4 = ReactionEquation([], [], ["I"])
+    assert merge_reactions(r1, r2, r3, r4) == ReactionEquation(
+        ["A", "B", "F"], ["C", "G", "H"], ["D", "I"]
+    )