A method of forming a combined dialkyl carbonate stream using a byproduct stream from a diaryl carbonate formation reaction, the method comprising the steps of: obtaining a byproduct stream from a diaryl carbonate formation reaction that contacts dialkyl carbonate with aromatic alcohol to produce diaryl carbonate and alkanol, the byproduct stream comprising alkanol, dialkyl carbonate, and an aromatic compound, wherein the aromatic compound comprises aromatic alcohol, aromatic ether, or both aromatic alcohol and aromatic ether, separating the byproduct stream to produce a first alkanol stream and a first dialkyl carbonate stream, wherein the first alkanol stream comprises alkanol, dialkyl carbonate, and less than 20 ppm aromatic compound, and wherein the first dialkyl carbonate stream comprises dialkyl carbonate, alkanol, and aromatic compound, contacting the first alkanol stream with oxygen and carbon monoxide in the presence of a catalyst, thereby creating a second dialkyl carbonate stream comprising dialkyl carbonate, alkanol, and water, separating the second dialkyl carbonate stream to produce a second alkanol stream and a third dialkyl carbonate stream, wherein the second alkanol stream comprises alkanol and dialkyl carbonate, and wherein the third dialkyl carbonate stream comprises alkanol, dialkyl carbonate, and water, and combining the first and third dialkyl carbonate streams to form a combined dialkyl carbonate stream comprising dialkyl carbonate, alkanol, water, and aromatic compound, thereby producing a combined dialkyl carbonate stream. obtaining a byproduct stream from a diaryl carbonate formation reaction that contacts dialkyl carbonate with aromatic alcohol to produce diaryl carbonate and alkanol, the byproduct stream comprising alkanol, dialkyl carbonate, and an aromatic compound, wherein the aromatic compound comprises aromatic alcohol, aromatic ether, or both aromatic alcohol and aromatic ether, separating the byproduct stream to produce a first alkanol stream and a first dialkyl carbonate stream, wherein the first alkanol stream comprises alkanol, dialkyl carbonate, and less than 20 ppm aromatic compound, and wherein the first dialkyl carbonate stream comprises dialkyl carbonate, alkanol, and aromatic compound, wherein the first alkanol stream comprises alkanol, dialkyl carbonate, and less than 20 ppm aromatic compound, and wherein the first dialkyl carbonate stream comprises dialkyl carbonate, alkanol, and aromatic compound, contacting the first alkanol stream with oxygen and carbon monoxide in the presence of a catalyst, thereby creating a second dialkyl carbonate stream comprising dialkyl carbonate, alkanol, and water, separating the second dialkyl carbonate stream to produce a second alkanol stream and a third dialkyl carbonate stream, wherein the second alkanol stream comprises alkanol and dialkyl carbonate, and wherein the third dialkyl carbonate stream comprises alkanol, dialkyl carbonate, and water, and wherein the second alkanol stream comprises alkanol and dialkyl carbonate, and wherein the third dialkyl carbonate stream comprises alkanol, dialkyl carbonate, and water, and combining the first and third dialkyl carbonate streams to form a combined dialkyl carbonate stream comprising dialkyl carbonate, alkanol, water, and aromatic compound, thereby producing a combined dialkyl carbonate stream.